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SKA.TEL.INFRA-SA.SE-TD-001
Commercial in confidence
Revision: 1
INFRA SA Technical Response
Document number................................................................................................ SKA.TEL.INFRA-SA.SE-TD-001
Revision .......................................................................................................................................................... 1
Classification .............................................................................................................. Commercial in Confidence
Author ................................................................................................................................................... SKA SA
Date ............................................................................................................................................... 2013/06/01
Client : SKA Organisation
Project : SKA Phase 1 (Pre-Construction Phase)
Type : Technical Response
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Document approval
Name Designation Affiliation Date Signature
Approved by C. van der Merwe
Senior System Engineer
SKA SA 6 June 2013
Approved by T. Cheetham General Manager: Infrastructure and Site Operations
SKA SA 7 June 2013
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Document history
Revision Date Of Issue ECP
/Number Comments
A 13 May 2013 NA Initial Issue
1 06 June 2013 NA Final issue for release
Document software
Package Version Filename
Word processor MS Word 2007 SKA TEL INFRA-SA SE-TD-001 Rev1.docx
Spreadsheet
Diagrams MS Visio 2007 Imbedded in word file
Company details
Name SKA SA Project Office
Physical/Postal
Address
17 Baker Street
Rosebank
Johannesburg
South Africa
Tel. +27 11 442 2434
Fax. +27 11 442 2454
Website www.ska.ac.za
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Table of contents
Applicable and reference documents ....................................................................................... ix
Executive summary ............................................................................................................... 10
Scope appreciation ............................................................................................................... 15
SKA1 Baseline Requirements Identification.......................................................................... 15
Data Processing on site versus Cape Town ......................................................................... 17
6. Technical response ........................................................................................................... 19
6.1. SKA.TEL.INFRA-SA.SMON – Site Monitoring ................................................................. 19
6.2. SKA.TEL.INFRA-SA.POWER – Infrastructure Power ....................................................... 23
6.3. SKA.TEL.INFRA-SA.ACC – Infrastructure Access............................................................ 44
6.4. SKA.TEL.INFRA-SA.WAS – Infrastructure Water and Sanitation ..................................... 51
6.5. SKA.TEL.INFRA-SA.BLDS – Infrastructure Buildings ...................................................... 56
6.6. SKA.TEL.INFR-SA.FOUND – Infrastructure Antenna Foundations ................................... 73
6.7. SKA.TEL.INFRA-SA.COMMS – Infrastructure Communication Systems ............................ 76
6.8. SKA.TEL.INFRA-SA.VEH – VEHICLES ............................................................................ 87
6.9. SKA.TEL.INFRA-SA.SEC – Site Security ......................................................................... 88
Annexure A .......................................................................................................................... 93
Annexure B .......................................................................................................................... 94
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List of tables Table 1: Overview of SKA1 Baseline Requirements Identification and Options .......................... 15
Table 2: Summary of SKA1 Power Load Requirement.............................................................. 24
Table 3: Quality of Power and Redundancy Requirement ........................................................ 24
Table 4: Sub-elements of the MeerKAT Power System ............................................................ 25
Table 5: Capacity of current MeerKAT Power System .............................................................. 26
Table 6: MeerKAT Power System - Quality of Power and Redundancy ...................................... 27
Table 7: Power System Design Implication of the Load growing from MeerKAT to SKA1 ............ 27
Table 8: Summary of upgrades for Option 1 ........................................................................... 31
Table 9: Opportunities for optimisation of Power Load Requirements ....................................... 33
Table 10: South African industry standard design lifecycles ..................................................... 39
Table 11: Drawing Register for Farm Roads ........................................................................... 48
Table 12: Daily Water Demand .............................................................................................. 51
Table 13: Maintenance requirements ..................................................................................... 54
Table 14: Operations and maintenance good practice procedures ............................................ 55
Table 15: Electromagnetic shielding ....................................................................................... 62
Table 16: Business Network and Non-telescope CAM requirements .......................................... 80
Table 17: Frequency allocations of the current radio system .................................................... 84
Table 18: Antenna foundation solutions ................................................................................. 94
Table 19: Relevant layers and their geotechnical parameters ................................................... 95
Table 20: Summary of piled and pad foundations ................................................................... 98
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List of figures
Figure 1: ESKOM bulk power infrastructure in relationship to the SKA site ................................ 29
Figure 2: Proposed Layout of new Astronomy Substation for Option 1 ..................................... 32
Figure 3: Typical Schematic – Distribution Network ................................................................. 34
Figure 4: Connection of the antennas to the existing Eskom 22kV overhead power lines ........... 35
Figure 5: Klerefontein support base workshop plan ................................................................. 57
Figure 6: KAPB Basement Plan .............................................................................................. 64
Figure 7: Proposed container layout ....................................................................................... 66
Figure 8: Proposed location of Data Containers to the North West of the KAPB ......................... 67
Figure 9: Showing plan of cable tunnel and staircase housing.................................................. 68
Figure 10: Showing section through containers, steel canopy, staircase & cable tunnel ............. 69
Figure 11: Conceptual SKA SA LAN and associated network .................................................... 77
Figure 12: BMS interfaces with the ILS and the telescope CAM ................................................ 82
Figure 13: Radio network showing links between Base Stations and Repeater stations .............. 85
Figure 14: Locality map of the SKA Observatory ..................................................................... 88
Figure 15: Security details required at the Site Complex, Meys Dam and Losberg ..................... 89
Figure 16: Details of Deproclamation of Provincial Road .......................................................... 91
Figure 17: Small strain stiffness profiles used in the design ..................................................... 97
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List of images Image 1: KAT-7 Wind Sensors ............................................................................................... 19
Image 2: MeerKAT Pole Mast ................................................................................................ 19
Image 3: Wind Sensor .......................................................................................................... 19
Image 4: STI Sensor Unit as deployed to Site ......................................................................... 20
Image 5: STI Electronics that is fitted inside the CMC container .............................................. 20
Image 6: RFI Monitoring Trailer ............................................................................................. 21
Image 7: RFI Monitoring Equipment ...................................................................................... 21
Image 8: ESKOM bulk power infrastructure in relationship to the SKA site – Aerial view ............ 30
Image 9: Connection of the antennas in the Spiral arms to the existing Eskom 22kV overhead
power lines – Aerial view ............................................................................................. 36
Image 10: Typical Farm Road (existing MeerKAT road) ........................................................... 45
Image 11: Typical platform around the Antenna Foundation for MeerKAT ................................ 46
Image 12: Airstrip after priming ............................................................................................ 48
Image 13: Meys Dam sewer package treatment plant ............................................................. 55
Image 14: Losberg Construction Camp sewer package treatment plant .................................... 55
Image 15: Klerefontein Workshops, office and stores constructed for MeerKAT ........................ 56
Image 16: Klerefontein Workshops, office and stores .............................................................. 57
Image 17: The Losberg Site Complex with Dish Assembly Shed and Pedestal Integration Shed on
the left ....................................................................................................................... 58
Image 18: Karoo array processor building and power building ................................................. 63
Image 19: Meys Dam Construction Camp ............................................................................... 70
Image 20: Losberg Construction Camp .................................................................................. 71
Image 21: A typical hand held radio transceiver ..................................................................... 83
Image 22: A typical mobile radio transceiver .......................................................................... 83
Image 23: Radio Base Station at security office ...................................................................... 83
Image 24: Radio Repeater antennas at the SENTECH High Site (100km from core site) ............ 84
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List of abbreviations
ABBL As-Built Baseline
AR Acceptance Review
ATP Acceptance Test Procedure
ATR Acceptance Test Report
BMS Building Management Systems
CAM Control and Monitoring
CBL Contract Baseline
CCTV Closed Circuit Television
CDR Critical Design Review
COAR Consolidated OAR
CoDR Concept Design Review
DBL Design Baseline
FAT Factory Acceptance Test
ICD Interface Control Document
ILS Integrated Logistics Support
IOBL Initial Operational and Support Baseline
JPL Jet Propulsion Lab
KAPB Karoo Array Processor Building
KAR Karoo Astronomy Reserve
KAT Karoo Array Telescope
KAT-7 7-Dish KAT system
LAN Local Area Network
LSP Local Survivable Processors
MeerKAT 64 dish array
NRF National Research Foundation
OAR Observation Action Register
OBL Operational and Support Baseline
PBL Product Baseline
PC Personal Computer
PCA Physical Configuration Audit
PDR Preliminary Design Review
POP Point of Presence
QBL Qualification Baseline
QTP Qualification Test Procedure
QTR Qualification Test Report
RBL Requirements Baseline
RFI Radio Frequency Interference
RFI Radio Frequency Interference
RR Requirements Review
SA South Africa
SAAO South African Astronomical Observatory
SEMP System Engineering Management Plan
SKAO Square Kilometre Array Organisation
STI SXXX
UPS Uninterruptible Power Supply
UTP Unshielded Twisted Pair
VLAN Virtual Local Area Network
VoIP
VSAT
Voice over IP
Very Small Aperture Transceiver
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Applicable and reference documents
Applicable Documents
[AD 1] PE Dewdney, SKA1 System Baseline Design, SKA-TEL-SKO-DD-001-1_BaselineDesign1
Rev 1.
Reference Documents
[RD 1] T Cheetham and C van der Merwe, INFRA SA Cost Breakdown Structure (CBS),
SKA.TEL.INFRA-SA.MGT-MD-006 Rev 1;
[RD 2] T Cheetham and C van der Merwe, INFRA SA Risk Register, SKA.TEL.INFRA-SA.MGT-MP-
003 Rev 1;
[RD 3] C van der Merwe and C Taljaard, INFRA SA ILS Proposal, SKA.TEL.INFRA-SA.SE-ILS-001 Rev 1;
[RD 4] T Cheetham and C van der Merwe, INFRA SA High-Level Schedule, SKA.TEL.INFRA-SA.MGT-MD-004 Rev 1;
[RD 5] Z Stegmann, Eskom Report: SKA Project: Maximum Power Available at the SKA Core Site
feedback, 13 May 2013;
[RD 6] A Tiplady, T. Monama, INFRA SA Array Layout Report, SKA.TEL.INFRA-SA.SE.RPT.001
Rev 1.
[RD 7] T Cheetham and C van der Merwe, INFRA SA Work Breakdown Structure (WBS),
SKA.TEL.INFRA-SA.MGT-WBS-001 Rev 1.
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Executive summary
This document has been structured according to the INFRA SA Work Breakdown Structure (WBS), which can be found in Reference Document [RD 7] – INFRA SA Work Breakdown Structure (WBS).
The INFRA SA Technical Response responds to the SKA1 Baseline Design (as detailed in Applicable Document [AD 1] – SKA1 System Baseline Design).
SKA.TEL.INFRA-SA.SMON – Site Monitoring
No requirements were defined in [AD 1] – SKA1 Baseline Design in terms of the provision of additional site monitoring equipment on site for SKA1.
An assumption has been made that additional wind sensors, STI Monitoring equipment and RFI
equipment will be added to the existing equipment currently deployed on site in South Africa. Provision has been made for additional infrastructure required for this equipment which includes the
following:
Foundations;
Trenching, power cabling and optic fibre ducting;
Connection boxes, fibre splice domes and optic fibre cabling (to be provided by SaDT);
Pole masts;
Earthing and lightning protection.
SKA.TEL.INFRA-SA.POWER – Infrastructure Power
POWER.GRID – Upgrade to Grid Power
Based on modelling and optimisation and still considering the SKA1 baseline design requirements, two options are presented to address the grid power supply to site for SKA1, namely:
Option 1: Upgrade of the grid power network (Total of 8.7MVA) required as per SKA1
baseline;
Option 2: Optimising the existing bulk power supply to the site to cater for the required load
(Total of 4.9MVA) as per amended requirements.
In both options, the outer skirt Antenna’s (21 Antennas) will be supplied by existing Eskom rural over-head power lines.
POWER.RETC – Upgrade to Electrical Reticulation (MV and LV)
Losberg Site Complex
As per the SKA1 Baseline Design, it is estimated that the total power requirement at the Losberg Site
Complex is 4.3MVA. Calculations of the total number of processor racks required for both MeerKAT and SKA1 amount to 316 racks. In order to respond to the SKA1 Baseline Design, Option 1 is
considered:
Option 1: Utilisation of the existing Karoo Array Processor building at the Losberg Site
Complex and the provision of a new SKA1 Container Shed housing RFI-shielded containers to
accommodate the additional processor racks. An assumption has been made that the RFI-
shielded containers will be supplied by the pulsar timing group. In addition to the above, the
INFRA SA Consortium has deviated from the SKA1 Baseline Design by assuming that the data
processing will take place on site as opposed to Cape Town. The reasoning for this deviation
is explained in Section 6.5.4. Should the proposed container option not be considered
feasible by the SKAO, the alternative option will be to construct a new building at the
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proposed “Astronomy Complex” where the 132kV/33KV substation will be constructed
(should this be required). This option has not been costed in response to the RfP.
Option 2: The INFRA SA Consortium has done further modelling on the SKA1 Baseline
Design where the proposed updated SKA1 requirement was identified to be 106 processor
racks in total. Based on this modelling, the total number of processor racks for MeerKAT and
SKA1 can be accommodated in the existing Karoo Array Processor building.
For both options, the 21 Spiral Arm Antennas are supplied from existing Eskom rural overhead power
lines in the area.
Antenna Core Array Reticulation
As per the SKA1 Baseline Design, the baseline array configuration received from the SKAO was
optimised by considering the local topography and EMC characteristics. Reference can be made to [RD 6] - INFRA SA Array Layout Report in the “Reference Documents” file which forms part of this
submission.
No additional MV feeder cables will be required from the existing Power Building on site to the SKA1 antennas. The total power requirement for the SKA1 antennas is 2.8MVA.
The existing three-leg MV cable ring network provided for MeerKAT will accommodate the required SKA1 loading requirements.
The existing on-site reticulation network will be expanded to supply the new core and outer skirt
antennas with power where the MV cables will cut into the existing ring network. Most of the existing 315kVA miniature substations provided for MeerKAT can be re-used for SKA1 with some units having
to be upgraded to 500kVA.
21 Antennas on the spiral arms with be supplied by existing Eskom rural overhead power lines.
It should be noted that the optic fibre design will need to be aligned with the existing MeerKAT and proposed SKA1 electrical reticulation design.
Existing Construction Camps Power Supply
The existing power and back-up supply to the Meys Dam and Losberg construction camps will be re-used for SKA1.
POWER.KAPB – Upgrade to KAPB Power (including DRUPS)
Option 1: In terms of the SKA1 Baseline Design, the total on-site power requirement is 8.7MVA, which includes the existing KAT-7, MeerKAT and SKA1 power requirements.
In order to meet the total site requirement of 8.7MVA, the following changes will be required:
Install two new 5MVA 33/22kV oil-type transformers outside the existing Power building and
remove existing 2x2,5MVA 33/22kV transformers;
Reserve the DRUPS inside the KAPB for 400V KAPB and site complex loads and install new
DRUPS auxiliary transformer to supply its ancillaries;
Install four containerised Rotary UPSs to supply the 3,4MVA to the antennas (1,25MVA units
in a 3 + N configuration, supplying at 22kV);
Install two containers containing necessary medium voltage switchgear, complete with HVAC,
fire detection, etc;
Install an additional 1,25MVA Rotary UPS inside the Power Building, to supply the 3,8MVA to
the local Losberg site loads including data centre components (thus the 400V loads).
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The INFRA SA Consortium has undertaken further modelling and has presented the following alterative option:
Option 2: Re-use the existing Power Building based on the proposed amended power requirements derived from the KAT-7 and MeerKAT experience for SKA1 (5MVA) with the following addition:
Install an additional two 1,25MVA DRUPS inside the provided space inside the existing Power
Building.
Maintenance considerations, reliability and availability have been discussed in terms of both options
provided.
SKA.TEL.INFRA-SA.ACC – Infrastructure Access
The following will be provided for in response to the SKA1 Baseline Design:
Sealing of the Provincial road to site;
The provision of basic farm roads to the SKA1 core antennas;
Re-use of existing farm roads which will be upgraded where required for the SKA1 outer
antennas;
The existing all-weather landing strip will be utilised for SKA1.
The SKA1 road layout is based on Reference Document [RD 6] - INFRA SA Array Layout Report in the
“Reference Documents” file which forms part of this submission.
Maintenance and material requirements for the above are furthermore described in Section 0.
SKA.TEL.INFRA-SA.WAS – Infrastructure Water and Sanitation
It is estimated that the SKA1 peak water demand will be 634kl/day. Existing boreholes on the MeerKAT site are able to supply approximately 570kl/day. Additional geo-hydrological studies on
water availability will be executed as part of the site characterisation studies. Additional boreholes will have to be provided for SKA1.
Additional water treatment and waste management plants will be provided at both Construction Camps for SKA1 and at the Losberg Site Complex.
SKA.TEL.INFRA-SA.BLDS – Infrastructure Buildings
BLDS.SBASE – Klerefontein Support Base (all buildings)
As per the SKA1 Baseline Design, an assumption has been made that the existing buildings at the Klerefontein Support Base will be re-used for SKA1. As indicated in the technical response, the draft
CON OPS document (under development by SKAO) is still under development and the Logistic Support Analysis (LSA) needs to be undertaken during Stage 1 to confirm that the existing buildings,
resources, spares etc. are sufficient for SKA1.
BLDS.SPLEX – Site Complex
Dish Assembly Shed and Pedestal Integration Shed
As per the SKA1 Baseline Design, an assumption has been made that the existing Dish Assembly Shed and Pedestal Integration Shed will be re-used for SKA1. It should however be noted that there
is a maximum width clearance of 18.155m in the Dish Assembly Shed and the width will need to be
re-assessed for the SKA1 dish design. Similarly, there is a maximum height and width restriction on the Pedestal Integration Shed which must be reassessed during Stage 1 to confirm that the SKA1
dish/pedestal can fit into both sheds.
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Karoo Array Processor Building
Reference can be made to Section 6.2.3 which describes the two options considered for the KAPB.
Additional HVAC units will be installed in the KAPB and a new HVAC unit will supply the RFI-shielded containers for Option 1 (SKA1 Baseline). The use of the existing KAPB as presented in Option 2
(optimised option) will require additional HVAC units provided in the KAPB.
Power Building
Reference can be made to Section 6.2.3 which describes the expansion of equipment within the
existing Power Building for the SKA1 Baseline Design (Option 1) and the alternative option considered (Option 2).
SKA1 Container Shed
The INFRA SA Consortium has proposed the construction of a Container Shed for SKA1 to house a number of RFI-shielded containers which will accommodate additional racks required in terms of the
SKA1 Baseline Design. The actual number of containers will be determined during Stage 1 if this option is considered.
Construction Camps
As per the SKA1 Baseline Design, the Losberg and Meys Dam construction camps will be re-used for SKA1. The existing camps will be able to accommodate the anticipated number of contractors
required for SKA1.
BLDS.HQ – Cape Town Headquarters
As per the SKA1 Baseline Design, floor space will be leased in Cape Town for SKA1. The SKA SA is
currently in discussion with their property agent to expand the office floor space at The Park, Pinelands. It is anticipated that SKA1 can also be accommodated within The Park building (however
this must be communicated urgently to the SKA SA).
As a second option, the SKA SA is in discussions with the Western Cape Government to secure land
with the intention of constructing a new building for SKA SA from 2017 onwards. Should the SKAO
wish to pursue this option further for SKA2, the SKAO would be required to enter into a separate Memorandum of Agreement with the SKA SA/NRF and the Western Cape Government in the near
future.
SKA.TEL.INFRA-SA.FOUND – Infrastructure Antenna Foundations
The SKA1 configuration is based on Reference Document [RD 6] - INFRA SA Array Layout Report in
the “Reference Documents” file which forms part of this submission.
The Antenna Foundation loading requirements for a 15m diameter dish have been based on the
loading requirements indicated in the SSG Request for Information, 2011.
Based on the local geotechnical conditions, it is anticipated that there will be a combination of concrete piled foundations and concrete pad foundations. The design and fabrication of the anchor
cage assembly (interface between the Antenna Positioner and the Antenna Foundation will be the responsibility of the DISH Consortium). The design of the Antenna Foundations makes provision for
fibre ducting (to be provided by the SaDT Consortium), sleeves housing the LV electrical cable and earthing and lightning protection.
SKA.TEL.INFRA-SA.COMMS – Infrastructure Communication Systems
No requirements were defined in [AD 1] – SKA1 Baseline Design relating to Communication Systems. The INFRA SA Consortium has made assumptions on requirements based on what has been
implemented for MeerKAT and what needs to be expanded to accommodate SKA1.
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COMMS.LAN – Upgrade to LAN System
The SKA SA is deploying LAN infrastructure for MeerKAT which interfaces with the long-haul optic
fibre backbone from site to Cape Town. This infrastructure provides access to a variety of
information services on site, Cape Town and in Johannesburg which include:
Scientific data (unidirectional to Cape Town);
Control and Monitoring of telescopes;
Webcam data for telescopes;
BMS Access Control;
Voice (IP telephony);
BMS CCTV and BMS Data;
Video Conferencing;
Internet Access and general data, mail etc;
Network authorisation.
It is anticipated that the MeerKAT LAN infrastructure will be expanded for SKA1 to provide the
following:
Extension of the LAN to the SKA1 Container Shed housing RFI shielded containers;
Expansion of the IP telephony platform;
General expansion of the LAN capacity.
COMMS.BMS –Upgrade to Building Management System
The existing Building Management System deployed for MeerKAT monitors the key performance factors of the infrastructure, which include the grid power supply; Rotary UPS power; Data Centre
cooling systems; fire systems; access control; lights, water systems, emergency power systems and Antenna power distribution. The BMS is an Ethernet based system and interfaces with the Integrated
Logistic Support (ILS) management system and the Telescope Control and Monitoring sub-system.
It is envisaged that additional BMS monitoring points will be required for SKA1 equipment deployed on the site.
COMMS.RADIO – Upgrade to Emergency Communication Radio System
An emergency communication network has been deployed on site for KAT-7 and MeerKAT to provide
a means for communication on site for contractors, SKA SA Staff and Security staff. The network
operates on 4 repeater frequency pairs, 2 simplex frequencies and 6 CTCSS. It is anticipated that the existing radio network will be re-used for SKA1 with the following additions:
Allocation of additional channels (additional tone frequency tone panels);
Depending on the coverage of the spiral arms, additional repeater stations may be required.
SKA.TEL.INFRA-SA.VEH – Vehicles
The SKAO has established a CON OPS Working Group to define the Concept of Operations for SKA1.
Further work is required during Stage 1 on the Concept of Operations and the Logistic Support Analysis to determine the logistical support, spares, vehicles and stores requirements for SKA1. An
assumption has been made that the existing maintenance vehicles on site will be re-used for SKA1. Additional utility vehicles, people transporters, skyjack and trailers will need to be provided for SKA1.
SKA.TEL.INFRA-SA.SEC – Site Security
The SKA SA has a Service Level Agreement in place with a registered Security Service Provider who provides security/access control at Klerefontein; at the access controlled boom gates entering the site
and on site. It is anticipated that additional security guards will be deployed for SKA1 when the
Provincial road to site has been de-proclaimed. This will further limit access control to the site in future.
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Scope appreciation
In responding to the RfP, the INFRA SA Consortium has followed the principle of making full-use of the Precursor (MeerKAT) infrastructure with a natural build-out to SKA1, while considering possible
options for the various Infrastructure and Power sub-elements in an effort minimise capital costs for the design and delivery of SKA1. The options presented in the Technical Response below have taken
Applicable Document [AD 1] - SKA1 Baseline Design into consideration with the requirements on the
Infrastructure and Power sub-elements identified in Table 1. The INFRA SA Consortium has undertaken further modelling and analysis on the SKA1 baseline requirements and proposed
alternative options which should be considered further during Stage 1.
Interface meetings and Interface Control Documents will be convened with all Consortia to define and
confirm requirements for the respective sub-elements related to infrastructure and the telescope
following the response to the RfP and during Stage 1. As can be seen from the options presented in the Technical Response below, assumptions have been made on certain requirements in an effort to
provide options for consideration and associated costs at this early stage.
SKA1 Baseline Requirements Identification
As per Applicable Document [AD 1] – SKA1 Baseline Design, the INFRA SA Consortium has extracted
the following Infrastructure and Power Requirements applicable to South Africa. Reference can be made to Table 1.
Table 1: Overview of SKA1 Baseline Requirements Identification and Options
WBS Element Baseline Doc Reference
Requirement Comment
SKA.TEL.INFRA-SA.SMON
SMON.WIND Table 5 Wind speed conditions for operating of Dish
INFRA to provide masts for wind sensors; actual sensors are TBD (to be included in ICDs in Stage 1)
SMON.WIND 16.1.5.3 Weather stations Utilise MeerKAT weather stations and add additional weather stations for SKA1 (INFRA only responsible for infrastructure related to weather stations)
SMON.STI Not stated STI System Assume current system on site will be expanded with 3rd antenna added
SMON.RFI Not stated RFI Monitoring systems Assume current on site systems will be used and expanded. INFRA to provide power, infrastructure, but actual systems are to be defined in Stage 1 (to be included in ICDs)
SKA.TEL.INFRA-SA.POWER
POWER Tables 22,23,24,25
CSP Power requirement The driver is the 250 racks for non-imaging (i.e. pulsar search). The SKA1 Baseline option as well as the optimised option has been considered. To be agreed via ICDs
POWER Not stated MGR,SDP,SADT Power requirement
Assumptions that have been made in response to the RfP to be agreed via ICDs in Stage 1
POWER Not stated DSH Power requirement Assumptions made in response to the RfP to be agreed via ICDs in Stage 1
POWER.GRID Para 16.1.1.2 (RSA) Provision of Power Re-use MeerKAT grid power supply; expand as required OR build new 132kV Line depending on Load (See above)
POWER.RETC Para 16.1.1.1 (RSA) Power Reticulation Re-use MeerKAT power reticulation and expand as required
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WBS Element Baseline Doc Reference
Requirement Comment
POWER.RETC Not stated Site Complex Power Re-use MeerKAT power provision to Site Complex and expand as required
POWER.RETC Para 16.1.3 Power Facility Re-use MeerKAT facility and expand as required using spare capacity already planned
POWER.RETC Not stated Antenna Core Array Reticulation
Re-use MeerKAT existing infrastructure and expand as required for additional 190 antennas
POWER.RETC Not stated Antenna Spiral Array Reticulation
Power to be provided by existing Eskom rural over-head power lines
POWER.RETC Not stated Construction Camps Power supply
Re-use MeerKAT infrastructure (power supply sufficient for SKA1)
POWER.RETC Not stated Power back-up requirements
Re-use MeerKAT back-up supply and expand as required using spare capacity
SKA.TEL.INFRA-SA.ACC Access (Roads)
ACC 16.1.4 Access (Roads) Re-use MeerKAT, expand as required
ACC.PROV Not stated Provincial Road from Carnarvon to Site
It is intended to upgrade the gravel road to a
surfaced standard.
ACC.AP Not stated Basic Farm roads to SKA1 Antennas
Re-use MeerKAT basic farm network and expand as required.
ACC.AP Not stated Platforms Add additional platforms for SKA1 antennas
ACC.AS 16.1.5.2 All weather landing Strip Re-use MeerKAT landing strip for SKA1
SKA.TEL.INFRA-SA.WAS Water and Sanitation
WAS 16.1.5.1 Water and Sanitation
(Construction camps)
Re-use MeerKAT water and sanitation infrastructure and expand for SKA1
WAS 16.1.5.1 Water and Sanitation
(Site Complex)
Re-use MeerKAT existing infrastructure
Not stated Water
(Road and Construction)
Utilise existing boreholes for MeerKAT and add additional boreholes for SKA1
SKA.TEL.INFRA-SA.BLDS Buildings
BLDS.SBASE 16.1.3 Klerefontein Support Base Re-use MeerKAT buildings. Expand as required, depending on requirements from Concept of Operations and Logistic Support Analysis
BLDS.SPLEX 16.1.3 Site Complex Re-use MeerKAT, expand as required
BLDS.KAPB 16.1.3 and
Appendix B
Central Signal processing facility
Option 1: Expand KAPB with RFI shielded containers to house additional racks
Option 2: Optimise the use of the existing facility within the growth margin (work required in Stage 1 to confirm power requirement to racks; number of racks and cooling requirement)
BLDS.CSHED Not stated SKA1 Container Shed Option 1: – this option is required to meet the requirements as per Appendix B of SKA1 Baseline document
BLDS.CAMP 16.1.3 Construction Camps Re-use MeerKAT construction camps
BLDS.HQ 16.2 Cape Town HQ Building Option 1: Lease additional space for SKA1 in current building or closely located building
Option 2: New Land and Building
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WBS Element Baseline Doc Reference
Requirement Comment
SKA.TEL.INFR-SA.FOUND - Antenna Foundations
FOUND 8.2 Array Configuration
(Position of Antenna Foundations)
Positions based on SKA1 baseline document. First-round optimisation done taking topography and EMC aspects into account. Further discussion and work is required on the configuration during Stage 1 by the Configuration Working Group
FOUND Table 6 Dish Size The SKA1-mid telescope antennas will be a mixed array of 64 13.5m diameter antennas for the MeerKAT array and 190 new 15m SKA1 antennas
FOUND Not stated Antenna Foundation loading and other requirements
Assumptions made based on SSG and MeerKAT. To be confirmed in ICDs during Stage 1.
SKA.TEL.INFRA-SA.COMMS - Communication Systems
COMMS.LAN Not stated LAN System Re-use MeerKAT Local Area Network and expand as required. Interfaces with SADT to be agreed in ICDs as part of Stage 1
COMMS.BMS Not stated BMS System Re-use MeerKAT Building Management System and expand as required for additional power and ancillary equipment
COMMS.BMS Not stated Emergency Communications Radio System
Re-use MeerKAT emergency communication network and expand as required for coverage at spiral arms
SKA.TEL.INFRA-SA.VEH – VEHICLES
VEH.BAK Not stated Additional Bakkies Additional bakkies (utility vehicles) will be required for SKA1.
VEH.TRANS Not stated Additional People Transporters
Additional People Transporters will be required for SKA1.
VEH.MAIN Not stated Additional Maintenance Vehicles
Existing MeerKAT maintenance vehicles will be utilized for SKA1. Additional maintenance vehicles/equipment will be required for SKA1.
SKA.TEL.INFRA-SA.SEC - Site Security
SEC Not stated Site Security Existing provision of security will be utilized for SKA1 and expanded
Data Processing on site versus Cape Town
As per Section 2 of Applicable Document [AD 1] – SKA1 Baseline Design, it lists the requirement for the Science Data Processor Centre or SKA1-mid Computer Centre to be in Cape Town. It is stated
that signals from the dishes will be transported to a central signal processing building (i.e. Karoo Array Processor Building) where they will be divided into narrow frequency channels and cross-
correlated with each other. Output data from the correlator will be transported to the Science Data Processor Centre in Cape Town. SKA SA undertook trade-off studies as part of the Concept Design
for MeerKAT on the proposed location of the Array Processor for MeerKAT. Three options were
considered, namely 1) On site at the Losberg Site Complex; 2) at the Klerefontein Support Base and 3) Split between the Site Complex and Klerefontein. At that point in time (2009), 5 Tbit/s raw data
needed to be transported between site and Klerefontein. Based on the number of transponders (160) required between the Site and Klerefontein, the capital cost of either splitting the Array
Processor between Site and Klerefontein or locating the Array Processor at Klerefontein was found to
be unfeasible from a cost point of view. It would be completely unfeasible from a capital cost based on this modeling to consider locating the Array Processor for MeerKAT in Cape Town.
A similar trade-off study was undertaken by SKA SA in response to the SSG as part of the Site Bid (Reference can be made to Annexure G.15- SKA SA Data Transport Costs – SSG Report). This study
confirmed that it would cost € 435,459,127 more to transport 400 Tbit/s of data to the Super
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Computer in Cape Town as opposed to processing data on the SKA site. The recommendation for on-site data processing was further supported by the Site Options Working Group (SOWG).
The SKA SA is still of the view that transporting 27 Tbit/s of data between Site and Cape Town will be too costly for SKA1. Further work will be required between the INFRA SA Consortium and the SaDT
Consortium during Stage 1 to align and confirm requirements and associated costs to reconfirm this
recommendation.
The relevant technical skills have and will be employed by the SKA SA to maintain the Karoo Array
Processor Building on-site. The same skills will be required to maintain SKA1 facilities. These skills include the Site Manager; Data Centre Manager (based in Cape Town and travelling to the Karoo);
Electrical and Mechanical Technicians; IT technicians and configuration engineers; Specialist
Contracted Engineers as and when required (Government licensed specialist engineers in terms of the Occupational Health and Safety Act); general maintenance and cleaning staff. The support staff will
stay in Carnarvon.
Based on the above considerations, two options have been considered for the data processing on
site, namely:
Option 1: Utilisation of the existing Karoo Array Processor Building and provision of a new
SKA1 Container Shed housing RFI-shielded container to accommodate additional racks. The
RFI-shielded containers will be supplied by the pulsar timing group (to be confirmed in Satge
1 as part of the ICD). This is seen as an interim solution until the Science Data Processor
Centre is built for SKA2;
Option 2: Utilisation of the existing Karoo Array Processor Building.
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6. Technical response
6.1. SKA.TEL.INFRA-SA.SMON – Site Monitoring
6.1.1. SMON.WIND - Site Monitoring – Wind Sensors
It is anticipated that the Site Monitoring Equipment will consist of the following:
Wind Sensors, WBS: SKA.TEL.INFRA-SA.APF.SMON.WIND;
The Site Test Interferometer (STI) , WBS SKA.TEL.INFRA-SA.APF.SMON.STI;
RFI Monitoring systems, WBS SKA.TEL.INFRA-SA.APF.SMON.RFI.
There is a wind sensor installed on a 10m pole mast at the KAT-7 radio telescope. Reference can be
made to Image 1.
For the MeerKAT phase, three additional wind sensors will be installed in the core area on 10m high pole masts, with optic fibre connections from the closest antenna. Image 2 shows one of the pole
masts and the optic fibre sleeves.
Image 1: KAT-7 Wind Sensors
Image 2: MeerKAT Pole Mast
The Wind sensor fitted to the mast is shown in Image 3:
Image 3: Wind Sensor
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For SKA1, it is assumed that there will be additional wind sensors in the spiral arms (2 per arm) as
well as 2 additional sensors in the SKA1 core area.
The interface between the Infrastructure sub-element and the telescope sub-element will be
documented in the relevant ICD.
a. This sub-element will consist of the following:
i. 2 x Wind sensors per spiral arm: i.e. 6;
ii. 2 x Core sensors (additional to MeerKAT);
iii. Total number required = 8.
b. 1 x Foundation (same design as MeerKAT);
iv. 1 x 10m high sectional pole mast (same design as MeerKAT);
v. 1x Earthing and lightning protection (same design as MeerKAT);
vi. The 100m of 40mm Fibre ducting from the closest antenna to the wind sensor must be planned for by the SaDT Consortium;
vii. 200m of 3 phase 400V power cable (10mm) from closest mini-substation to the wind sensor;
viii. The optic fibre sleeve and Power cable should be co-located in a 1000mm deep
common trench.
The responsibility of supplying the 8 wind sensors (actual equipment) will be agreed upon with the
SKAO and defined in the relevant ICD.
6.1.2. SMON.STI – Site Monitoring – STI System
The STI system was developed by the Jet Propulsion Laboratory, California Institute of Technology
and deployed to the site as part of the SKA Site Bid site measurement campaign.
The system consists of two sensor units, underground fibre cables and an electronic rack. Image 4
shows one of the STI sensors deployed on the MeerKAT/SKA site. Image 5 shows the STI electronics
rack that is fitted inside the RFI screened CMC container.
Image 4: STI Sensor Unit as deployed to Site Image 5: STI Electronics that is fitted inside the CMC container
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It is assumed that the SKA1 requirement will be to provide a third sensor unit.
The Infrastructure element will provide the following:
Foundations for the sensors (1m x 1m x 500mm);
Connection box and fibre splice dome;
Optic fibre duct (estimate 300m) which will be provided by the SaDT Consortium;
200m Optic fibre cable to be provided by the SaDT Consortium;
200m Common trench which houses the power cable and optic fibre cable;
Electrical Power (3 phase, 4 wire, 400v, 300m).
The upgrade of the STI system will be done by the SKAO. The site monitoring system will be provided by JPL.
6.1.3. SMON.RFI – Site Monitoring – RFI System
RFI Monitoring equipment includes the following:
RFI monitoring trailers;
Portable RFI monitoring equipment;
Fixed RFI monitoring equipment.
Image 6 shows the RFI monitoring trailer being deployed on site.
Image 6: RFI Monitoring Trailer
Image 7 shows some of the portable RFI monitoring equipment currently being used on site.
Image 7: RFI Monitoring Equipment
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For SKA1 it is assumed that a permanent RFI monitoring station will be established on the Losberg Hill, which is closely located to the current MeerKAT webcam installation.
The Infrastructure element will provide the following:
Foundation (same design as the MeerKAT webcam);
Lattice mast (same design as MeerKAT) but 10m in height;
Earthing and lightning protection (same as MeerKAT);
100m 40mm Optic fibre sleeve from current webcam position to RFI monitor position which
will be provided for by the SaDT Consortium;
100m 3 phase 400V power cable (10mm) from the current MeerKAT webcam position to the
RFI monitor position.
The RFI monitoring equipment including antennas will be provided by another Consortium / telescope
sub-element.
The interface between the infrastructure and telescope elements will be documented in the relevant ICD.
Technical Risks and proposed mitigation measures
Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register which describes the
technical risks and proposed mitigation measures for this sub-element.
Capital, Operational and Maintenance Costs
Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown Structure for the
capital costs applicable to this sub-element.
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6.2. SKA.TEL.INFRA-SA.POWER – Infrastructure Power
Introduction
The aim of the INFRA SA Consortium is to provide the most reliable power network that meets SKA1
requirements at the most economical life-cycle cost. Various options will be considered, amongst which are the utilisation of the existing power infrastructure implemented for the MeerKAT telescope
and the provision of a new 132kV grid power connection as developed for the Site Bid submission. Optimisation requirements to enable the implementation of these proposals will be identified.
In order to meet the MeerKAT power requirements, SKA SA have constructed a 33kV extension to the
existing Eskom Karoo 66kV/22kV substation, and constructed a 33kV powerline from Karoo Substation to the SKA Core site, with a length of approximately 110 kilometres. The capacity of this
point of supply is limited, with this initial proposal identifying some of the possible SKA1 estimated power requirements that could be considered for optimisation in order to reduce the overall SKA1
power capacity requirement to the capacity which could be supplied off the existing infrastructure.
One alternative identified here for consideration is the implementation of the previously developed option of a new 132kV grid connection. Stage 1 will consider these plus other options, followed by a
down-select process to be taken forward and developed in Stage 2.
This section describes the Power sub-element and includes:
a. The Power requirement, including reference and assumptions;
b. The MeerKAT power system (to be re-used / expanded for SKA1);
c. The implications of growth in load from MeerKAT to SKA1;
d. The SKA1 power system design options, identified as basis for costing:
i. Option 1 – As per the SKA1 Baseline Design Document [AD 1];
ii. Option 2 – Optimised for use of MeerKAT power system.
e. Verification of SKA1 Power system.
Power Requirement - Function of the Power sub-element
The main function (i.e. critical function) of the Infrastructure Power sub-element is to supply electrical power to the following:
a. The Telescope Antennas (DSH element) both in the core area and the spiral arms;
b. The Telescope processing and control elements (CSP, SDP, MGR) in the Processing facility;
c. The Signal and Data Transport element (SADT);
d. The provision of power to the cooling of CSP, SDP, MGR and SADT racks in the processing facility;
e. Other telescopes (KAT-7, PAPER and C-BASS).
A secondary function of the Infrastructure Power sub-element is to supply power to the following:
f. Site Monitoring systems (wind sensors, STI, RFI monitoring);
g. The various Buildings and Construction Camps (lights, power sockets, etc.);
h. The pumps etc. of the water and waste treatment systems;
i. The on-site communications systems (LAN, BMS and Radio systems).
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Power Requirement – Load Requirement
Table 2 provides a summary of the power load requirement for SKA1:
Table 2: Summary of SKA1 Power Load Requirement
Element / Sub-element Power requirement
[kVA] Reference / Assumption
Dis
h
64 MeerKAT + 190 SKA1 Dishes 3 747.0 Estimated load of 14.75kVA per dish
Source is initial estimates from Dish Consortium, to be
confirmed during Stage 1
Sub. Dish 3 747.0
Pro
cess
ing F
aci
lity
CSP element 2 629.4 [AD 1] - SKA1 Baseline Design document, tables
22,23,24 and 25
MGR element 40 Source is initial estimates from MGR Consortium, to be
confirmed during Stage 1
SDP element 300 Source is initial estimates from SDP Consortium, to be
confirmed during Stage 1
SADT element 31.3 Source is initial estimates from SADT Consortium, to
be confirmed during Stage 1
INFRA-SA.COMMS
LAN and BMS sub-elements
12.5 Re-use MeerKAT systems
INFRA-SA.BLDS.KAPB
Cooling for processing facility
1 269.7 Based on design of MeerKAT HVAC system
Sub. Processing facility 4 282.8
Oth
er
KAT-7 and PAPER 67.5 Based on MeerKAT estimates
Buildings and Construction Camps 619.9 Re-use MeerKAT systems
Sub. Other 687.4
Total Power Requirement 8 716.7
Power Requirement – Quality of Power and Redundancy
Table 3 provides a summary of the Quality of Power and Redundancy requirements for SKA1:
Table 3: Quality of Power and Redundancy Requirement
Power Parameter Requirement Reference / Assumption
Nominal Voltage
(for Dish and other elements)
400V (3 phase) South African Standard used on MeerKAT
To be confirmed during Stage 1
Voltage tolerance
(drop or rise)
± 5% ESKOM Standard used on MeerKAT
To be confirmed during Stage 1
Nominal Power factor
(for Dish and other elements)
0.8 Assumption based on MeerKAT
To be confirmed during Stage 1
Redundant power for dishes Full redundant power source
(i.e. Primary and standby)
Assumption based on MeerKAT
To be confirmed during Stage 1
Redundant power for CSP, SDP, MGR
and SADT
Full redundant power source
(i.e. Primary and Standby)
Assumption based on MeerKAT
To be confirmed during Stage 1
Uninterruptable (UPS) power for Dish Not required MeerKAT dishes require UPS power
SKA1 requirement to be confirmed during Stage 1
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Power Parameter Requirement Reference / Assumption
Uninterruptable (UPS) power for CSP,
SDP, MGR and SADT
UPS power required Assumption based on MeerKAT
To be confirmed during Stage 1
MeerKAT Power System – Description of Current System
The current MeerKAT power system consists of the following sub-elements:
a. The Prime power source from ESKOM (INFRA-SA.POWER.GRID), including:
iii. The ESKOM 66kV supply to the Karoo substation;
iv. The Karoo substation upgraded for MeerKAT;
v. The 33kV grid power line.
b. The backup and UPS power source at the KAPB facility (INFRA-SA.POWER.KAPB):
vi. 33kV Transformers and switchgear;
vii. The Diesel Rotary UPS systems (N+1 redundancy);
viii. The 22kV Transformers and switchgear;
ix. 400V feeds to the processing facility (dual redundant).
c. The reticulation to the Dishes (INFRA-SA.POWER.RETIC):
x. 22kV network to the Dishes (dual redundant feeds);
xi. The 22kV/400V minisubs (maximum 5 dishes per mini-substation).
Table 4 shows some of the sub-elements of the MeerKAT Power system:
Table 4: Sub-elements of the MeerKAT Power System
Karoo 66kV/33kV Substation (vicinity Carnarvon) 33kV grid line with Voltage Boosters
22kV/400V Mini-substation (part of on-site electrical reticulation)
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MeerKAT Power System - Capacity
Table 5 provides an overview of the capacity of the current MeerKAT power system:
Table 5: Capacity of current MeerKAT Power System
Power Sub-element Capacity Growth available for SKA1
PO
WER
.GR
ID
ESKOM 66kV supply
to Karoo sub station
The current ESKOM 66kV supply
can provide 10MVA to the Karoo
substation
The 10MVA capacity is allocated a follows:
2.5MVA capacity for local towns and farms
7.5MVA capacity available for SKA1
(upgrades are possible but need to be investigated)
Karoo substation The Karoo substation was upgraded
for MeerKAT with 2 x 5MVA
66kV/33kV transformers, i.e. total
capacity of 10MVA
5MVA capacity available for SKA1/MeerKAT
This can be increased to 10MVA (to be confirmed during
Stage 1) capacity by running two transformers in parallel,
but the provision of a possible spare transformer for
redundancy / repair time needs to be investigated during
Stage 1
33kV Grid Line The new 33kV grid power line
constructed for MeerKAT can
provide 4.9MVA
(limited by voltage booster required
for the length of the line)
4.9MVA available for SKA1/MeerKAT
The voltage booster design can be upgraded to provide 6
MVA capacity
PO
WER
.KAPB
Power facility The power facility has
2 x 2.5MVA transformers
i.e. total capacity of 5MVA
Full 5MVA capacity is available for SKA1/MeerKAT
Upgrades might be required, due to technical
considerations such a fault levels
Standby Power
(Diesel)
For MeerKAT, 3 x 1.25 MVA standby
generators are installed with a N+1
configuration
(i.e. 2.5MVA)
The facility design (space, busbars,
switchgear, etc) has a total capacity
of 5MVA
Full 5MVA capacity is available for SKA1/MeerKAT
Uninterruptable (UPS)
Power
For MeerKAT, 3 x 1.25MVA Rotary
UPS system are fitted in a N+1
configuration
(i.e. 2.5MVA)
The facility design (space, busbars,
switchgear, etc) has a total capacity
of 5MVA
Full 5MVA capacity is available for SKA1/MeerKAT
PO
WER
.RETIC
22kV reticulation to
Dishes
The MeerKAT 22kV reticulation has
a capacity of 7.6MVA
Full 5MVA capacity is available for SKA1
22kV to 400V Mini-
substations
For MeerKAT 21 x 315kVA mini-
substations are provided with a
limitation of 5 Dishes per mini-
substation
(i.e. less than 10% of total array)
It is assumed that for SKA1 up to 26 dishes (10% of
array) can be added per mini-substation. Additional mini-
substations can be added to the 22kV reticulation
network to provide the full 5MVA capacity
The 21 dishes on the spiral arms will be supplied by
existing ESKOM rural overhead power lines (new mini-
substations to be added).
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MeerKAT system - Quality of Power and Redundancy
Table 6 provides a summary of the Quality of Power and Redundancy requirements for the current
MeerKAT power system:
Table 6: MeerKAT Power System - Quality of Power and Redundancy
Power Parameter MeerKAT Value Comments
Nominal Voltage
(for Dish and other elements)
400V (3 phase) South African Standard
Voltage tolerance
(drop or rise)
± 5% ESKOM Standard
Nominal Power factor
(for Dish and other elements)
0.8 Power factor correction is done by the DRUPS
systems as well as reactors fitted to the mini-
substations and at the power facility
Reliability of ESKOM Power NRS 048 limits Power supply was monitored by the SKA SA and
meets the standard
Redundant power for dishes Full redundant power
source (i.e. Primary and
standby)
Primary source is ESKOM
Standby is Diesel Generators
Diesel Generators have N+1 redundancy
Redundant power for processing facility
(including cooling)
Full redundant power
source (i.e. Primary and
Standby)
Primary source is ESKOM
Standby is Diesel Generators
Diesel Generators have N+1 redundancy
Processing facility has dual redundant feeds (A bus
and B bus)
Uninterruptable (UPS) power for Dish Full UPS to all dishes Rotary UPS systems integrated with Diesel
Generators
N+1 redundancy
Uninterruptable (UPS) power for
processing facility (including cooling)
Full UPS Rotary UPS systems integrated with Diesel
Generators
N+1 redundancy
Growth from MeerKAT to SKA1 - Overview of Implications
Table 7 provides a high level summary of the system design implication of the load growing from MeerKAT to SKA1:
Table 7: Power System Design Implication of the Load growing from MeerKAT to SKA1
Project
Phase Load Growth
System design Implications
POWER.GRID POWER.KAPB POWER.RETIC
MeerKAT Up to 2.5MVA Nil Nil Nil
SKA1
2.5MVA to 5MVA Upgrade Voltage Boosters Add Rotary UPS systems Add Mini-substations
5MVA to 6MVA Upgrade Voltage Boosters
Spare 5MVA transformer at
substation
Add Rotary UPS systems
Replace 33kV/22kV
Transformers
Add Mini-substations
6MVA to 8.7MVA Build new 132kV power
line from KRONOS
Add Rotary UPS systems
Replace 33kV/22kV
Transformers
Add Mini-substations
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SKA1 Power System - Overview of Defined Options
Two options have been identified for the SKA1 power system:
a. Option 1 (SKA1 Baseline Design option) – Upgrade to the MeerKAT power system in order to meet the 8.7MVA maximum power demand;
b. Option 2 (Optimised Option) – Utilise the 5MVA available by optimisation of the power load
requirement.
In addition to these two options, a possible design solution for the supply of power to the Dishes in
the spirals is also described.
SKA1 Power System - Description of Option 1 (SKA1 Baseline Design Option)
In order to provide the maximum demand of 8.7MVA (refer Table 2), the following option has been
identified based on the recommendations in the SSG report:
a. Additions to the KRONOS substation;
b. New 132kV line from KRONOS substation;
c. New Astronomy substation;
d. Changes to existing 33kV grid power line.
Figure 1 shows the ESKOM bulk power infrastructure in relationship to the SKA site, including the CUPRUM, KRONOS and KAROO substations:
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Figure 1: ESKOM bulk power infrastructure in relationship to the SKA site
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Image 8: ESKOM bulk power infrastructure in relationship to the SKA site – Aerial view
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Table 8 provides a summary of upgrades to the Power system for this option:
Table 8: Summary of upgrades for Option 1
Power System – Sub-element Upgrade for Option 1 Reference
Upgrades to KRONOS
400kV/132kV transmission station
400kV/132kV (2 x 250MVA) transformer
bay expansion with transformers
Drawing
107102–SSG–ELE–0010.
New 132kV power line for 110km from
KRONOS to ASTRONOMY
New monopole structure, overhead power
line 110km from KRONOS to ASTRONOMY
Drawing
107102–SSG–ELE–0010.
New ASTRONOMY Substation The proposed new 132kV/33kV Eskom
substation “Astronomy” is located adjacent
to the proposed new Site complex and
Processor building (part of SKA2)
Modification to 33kV grid power line Modifications to feed existing MeerKAT
33kV line from the new ASTRONOMY
substation
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Figure 2 shows the proposed layout of the new ASTRONOMY substation:
Figure 2: Proposed Layout of new Astronomy Substation for Option 1
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SKA1 Power System - Description of Option 2 (Optimised)
Table 9 provides an overview of the opportunities for optimisation of the power load requirements.
These are initial estimates from the INFRA SA Consortium and need to be confirmed with the various elements such as the DISH, CSP, etc. during Stage 1 of the Pre-Construction design phase and
documented in the ICD documents.
Table 9: Opportunities for optimisation of Power Load Requirements
Power Load
Sub-element
Current Estimated
Value Opportunity for Optimisation
DISH element
Total Power
14.75kVA per dish
254 dishes
3 747kVA total
For each kVA of power optimisation per dish, the total load will reduce by
254kVA.
Initial discussion with the DISH consortium indicates that a load of 12kVA
per dish is achievable, i.e. total reduction of 424kVA can be
investigated.
DISH element
Power to Spirals
14.75kVA per dish If 21 dishes in the spiral arms are supplied from the rural ESKOM supply
rather than the KAPB facility, a saving of 310kVA can be investigated.
The backup power to stow the dish during high wind conditions needs to
be investigated during Stage 1.
CSP element
Non-Imaging (Pulsar
search)
250 racks
20kW per rack (max)
8kW per rack (avg)
2 500kVA total
Initial discussions with the CSP Consortium indicate that a reduction to
40 racks with 6kW each can be investigated.
This reduces the power for this element from 2.5 MVA to 300kVA, i.e. a
saving of 2 200 kVA.
Processing facility
Cooling
Power for cooling 315
racks
1 269kVA total
If the CSP non-imaging is reduced as indicated above, the power for
cooling can be reduced to 344kVA, i.e. a saving of 926 kVA
Construction facilities
and security
196kVA Remove this from the Rotary UPS supply (but keep on ESKOM supply)
Rotary UPS Load
(optimised)
5 000kVA available The total opportunity for Rotary UPS load optimisation is 4 056kVA
i.e. reduce the Rotary UPS load from 8 717kVA to
4 661kVA
Grid Power Line Load
(optimised)
6 000kVA available The total opportunity for grid line load optimisation is 3 860kVA
i.e. reduce the Rotary UPS load from 8717kVA to
4 857kVA
Discussion of Option 2
Table 9 shows that with the proposed optimisation of the SKA1 load, power can be supplied from the current MeerKAT power system.
During the Stage 1 design, the following needs to be investigated in further detail:
a. The opportunities for load optimisation from other SKA1 elements (DISH,CSP etc);
b. The opportunities for load optimisation from the INFRA SA elements (Buildings etc);
c. Technical design aspects such as voltage drop, power factor corrections, fault currents etc.
SKA1 Power - Supply of Power to Antennas in the SKA1 Core
As part of the existing KAT-7 and MeerKAT radio telescope, a Random Electrical Reticulation design
approach was followed to provide power from the Power building at the Site Complex to the antennas.
This design allows for an optimised cable route path for both MV and LV voltage cables which are
clearly marked by cable markers every 200m and GPS coordinates. The electrical reticulation design also included the provision of optic fibre ducting installed in a common power/optic fibre trench to
reduce capital costs.
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22 Mini-substations have been provided on site for the MeerKAT antennas.
The typical schematic presentation of the MeerKAT Distribution Network is indicated in Figure 3. The
same design philosophy will be followed for the SKA1 design.
Figure 3: Typical Schematic – Distribution Network
No additional MV feeder cables from the Power building to the SKA1 core antennas will be required as the existing MeerKAT MV ring network can accommodate the SKA1 loading requirements.
The current MeerKAT electrical reticulation network will be expanded to supply the SKA1 antennas
through the provision of additional MV cables to the antennas. Due to the density in the MeerKAT/SKA1 core, it is foreseen that existing MeerKAT 315kVA mini-substations will be utilised to
accommodate the SKA1 loading requirements. Some of the mini-substations will need to be upgraded to 500kVA units.
Reliability, Availability and Maintainability (RAM) modelling of the SKA1 electrical network will be
executed as part of Stage 1. This needs to be done to confirm the maximum number of SKA1 antennas which could be out of order due to fault conditions on a specific mini-substation. For SKA1
costing purposes, it has been assumed that there will be 1 mini-substation/26 antennas.
Reference can be made to the following Drawings in Annexure A of this document:
Power.Retc.EP-0103 – Proposed New SKA Phase 1 Dish Positions Sheet 1 of 2
Power.Retc.EP-0104 – Proposed New SKA Phase 1 Dish Positions Sheet 2 of 2
Power.Retc.EP-0108 – Electrical Reticulation Random Layout
SKA1 Power – Supply of Power to Antennas in the Spiral Arms
The Spiral Arms antenna array reticulation design was divided into two sections:
a. The first section’s design allowed for some antennas on the spiral arms to be reticulated by
extending the existing KAT-7/MeerKAT electrical reticulation network;
b. The second section’s design allowed for the 21 antennas on the Spiral Arms to be supplied from existing Eskom rural over-head power lines. This will be part of the 22kV section of the
KAROO substation.
c. A 2km separation distance was allowed for between any antennas and overhead line
networks, based on SPDO methodology used by the Configuration Task Force (CTF) for optimisation of the SKA configuration in response to the SSG / site group Request for
Information, 2011.
Figure 4 shows the proposed connection of the antennas in the Spiral Arms to the existing Eskom 22kV rural overhead power lines:
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Figure 4: Connection of the antennas to the existing Eskom 22kV overhead power lines
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Image 9: Connection of the antennas in the Spiral arms to the existing Eskom 22kV overhead power lines – Aerial view
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SKA 1 Electrical Reticulation and Rotary UPS Maintenance considerations
The Power Building was designed to serve the role of a central substation / hub - a single point to
which the utility (Eskom) supply can connect and from which KAT-7, PAPER and MeerKAT antennas and ancillary loads are subsequently fed from. In addition to offering this central distribution and
control feature, an arrangement of diesel Rotary uninterruptible power supplies (DRUPSs) within the
building offer continuity of supply to the MeerKAT and existing loads.
The building is currently supplied via the Karoo substation at 33kV through an overhead line feeder
(Hare conductor) and underground cable (50 mm² three cored XLPE) for the last few hundred meters.
Inside the Power Building the 33kV is stepped down to 22kV and 400V, with voltage stepping being
implemented via two sets of distribution transformers, located inside the Transformer Room:
Two 2,5 MVA 33kV/22kV transformers (designed to operate in parallel) - 5 MVA Installed
Capacity;
Two 1,6 MVA 22kV/0,4 kV transformers (designed to operate un-paralleled) - KAPB and local
site load.
For MeerKAT, three Rotary UPS units are installed.
Each of these three Rotary UPSs are rated at 1 MW / 1,25 MVA (totalling 3 MW / 3,75 MVA); but their
configuration while powering the MeerKAT installation will be “N+1”, meaning only 2 MW / 2,5 MVA will be available for use as one unit will be in hot standby at all times (to allow for maintenance or
single unit failure without shutting down or load shedding).
The MeerKAT Rotary UPS system is modular of nature, meaning that additional Rotary UPSs can be
installed in parallel with these three in order to increase the total UPS output rating (provided they are
of the same size and manufacture).
For this purpose physical space has already been allocated inside the Power Room for the placement
of an additional two units, making physical allowance thus for an increase in the total power output of the Rotary UPS system from the current (MeerKAT) output of 3 MW / 3,75 MVA (or 2 MW / 2,5 MVA
in “N+1” mode) up to a total of 5 MW / 6,25 MVA (or 4 MW / 5 MVA in “N+1” mode) - such outputs available in “conditioning” i.e. non-emergency mode as well as “standby” i.e. diesel-powered mode.
The Rotary UPS installation can with minimal design and installation effort be expanded to five of
1,25MVA units, offering thus Installed Capacity of 6,25 MVA and Firm Capacity of 5 MVA.
Each 1,6 MVA transformer is currently being installed for the MeerKAT feed into a bus section of the
main low voltage distribution board. Each bus section of the board, being rated at 2 500 A, will be able to supply the full anticipated Losberg Site Complex load (MeerKAT data racks and cooling). This
redundancy is to be implemented via dual feeds from this main board to the sub-distribution boards,
each feeding in turn the racks and rack air conditioning systems.
In terms of building structures, for MeerKAT, the Power Building section of the KAPB is currently
being constructed to consist of three switch/control rooms, a power (generator) room and a transformer room (plus two passages serving as intake and exhaust ducts).
Power Room: this room will house the Rotary UPSs, generator transformers, Rotary UPS
chokes, and the diesel day tanks for up to 5 Rotary UPS units;
MV Room (Domestic): this room will house “Domestic” MV switchgear (33kV and 22kV panels
not associated with the Rotary UPS system). The switch panels in this room are all of the fixed
pattern gas (SF6) insulated busbar type (with vacuum circuit breakers);
Transformer Room: this room will house the distribution transformers (two 1,6 MVA and two
2,5 MVA transformers), as well as a Rotary UPS auxiliary transformer (500 kVA), and zigzag-
type earthing transformer with 140 Amp neutral earthing resistor (space is available for the
installation of an additional resistor should the need arise);
Control Room: this room will house the main 400 V distribution panel to the KAPB building
(from whence the KAPB data centre loads as well as all 400 V site loads are fed), as well as
the UPS system’s control panels;
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UPS MV Room: this room will house the 22kV switchgear of the Rotary UPS system. The
switch panels in this room are all of the withdrawable air insulated busbar type (with SF6
circuit breakers).
Although the Rotary UPS system is inherently modular, some physical, functional and safety
constraints precludes the extension of the MeerKAT DRUPS system to more than 5 units. The
constraints being amongst others the dimensions of the UPS MV, Control and Transformer rooms inside the building, the dimensions of the trenches, electromagnetic compatibility, and current ratings
of installed equipment.
Option 1 (SKA1 Baseline Design)
In order to increase the current Power building’s capacity to accommodate this maximum site loading
for the SKA1 Baseline Design requirement, the following changes are proposed:
Increase the size of the main 33kv/22kV transformers;
Reserve the Rotary UPS units inside the KAPB for 400 V KAPB and site complex loads;
Provide new additional containerized backup power to the 22kV underground cable networks
supplying the antennas.
This is proposed to be implemented as follows:
Install two new 5 MVA 33kV/22kV oil type transformers outside the building;
Install four containerised Rotary UPSs to supply the 3,4 MVA to the antennas (1,25 MVA units
in a 3 + N configuration, supplying at 22kV);
Install two containers containing necessary medium voltage switchgear, complete with HVAC,
fire detection, etc.;
Install new DRUPS auxiliary transformer to supply its ancillaries;
Install an additional 1,25 MVA Rotary UPS inside the Power Building, to supply the 3,8 MVA to
the local Losberg site loads including data centre components (thus the 400 V loads);
Remove the existing 2 x 2,5 MVA 33kV/22kV transformers from the building;
In their positions install two new 2 MVA 22kV/0,4 kV transformers - these to supply the RFI-
shielded containers containing the additional racks which cannot fit inside the KAPB via a new
3 000 A dual bus LV panel outside the building;
If needed (in order to distribute loads between the two installations) some of the site complex
loads (e.g. construction sheds) can be moved over from the KAPB LV supply to the antenna
supply, using old transformers.
Option 2 (Optimised solution)
In order to increase the current Power building’s capacity to accommodate a maximum site loading
indicated in the alternative solution, the following network changes are proposed:
Install an additional two 1,25 MVA Rotary UPS units inside the provided space inside the
Power Building.
By implementing either option, all loads listed will be supplied with conditioned power and all of the
site reticulated antennas would have the function of stowing when needed. All connected loads will be
independent of external grid faults and would operate normally.
Availability and reliability of the Rotary UPS units
The Rotary UPS system will offer an automatic and break-free changeover from the mains (Eskom) power supply to diesel generator power when the former fails. Furthermore:
The Rotary UPS system can be programmed to offer a redundancy of N + 1 for the maximum
power required by the SKA1 installation;
The reliability of the complete facility is estimated to have a Mean Time Before Failure (MTBF)
of more than 10,000 hours;
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The N + 1 redundancy configuration will allow for maintenance to be done on any one of the
Rotary UPS units without interruption of power supply to the loads;
Major functions of the medium voltage equipment and the Rotary UPS units will be relayed to
and thus monitored by the building management system (BMS) which is currently in the
process of being installed;
The existing bulk diesel storage tanks (three tanks containing 23 kilolitre each, located next to
the KAPB building), plus the new day tanks which are proposed to be installed or in the
process of being installed (one 1000 litre day tank per Rotary UPS), offering a total capacity of
just over 70 kilolitres, will allow the site to run at full load for over 48 hours for Option 2
(5MVA) - the fuel consumption of 5 machines at full load in N+1 mode being 1 450 litres /
hour. However, for Option 1 (7,8 MVA), in order to provide 48 hours backup another bulk tank
should be installed in order to increase the total capacity to 106 kilolitre (consumption of 8
machines being 2 200 litre / hour in N+1 mode).
SKA 1 Electrical Reticulation and Rotary UPS Maintenance considerations
Electrical Reticulation components
Table 10 illustrates the South African industry standard design lifecycle of the different major electrical components as well as the typical maintenance periods:
Table 10: South African industry standard design lifecycles
Item Description Industry Design
Lifecycle Period
MTTR
(Mean Time To Repair)
Typical Maintenance
Period
3.3kV 25kVA Transformer 25 Years
Dependent on SKA Staff and
Maintenance Program
6 months – Visual
inspection
315kVA Transformer 25 Years 6 months – Oil test
SF6 Ring Main Unit – Tank 30 Years 6 months – Visual
inspection
SF6 Ring Main Unit – Switch
Mechanism 2000 Switching cycles
6 months – Visual
inspection
22kV XLPE Cables 25 Years -
LV PVC Cables 20 Years -
Rotary UPS units
Regular service intervals need to be scheduled for the Rotary UPS units. Minor services of the Rotary
UPS units will be done at the Site Complex. Once larger services, such as the replacement of bearings are required, the Rotary UPS unit will be replaced with a refurbished unit. The unit which requires
maintenance will be serviced at the Supplier’s workshop as part of a Service Level Agreement. Bypass switches allow for maintenance to be done on any one of the Rotary UPS units with no interruption to
the power supply. Maintenance on other electrical ancillary equipment includes the following:
The distribution transformers used inside the Power Building will be of the oil-free (dry) type,
thus requiring minimal servicing;
Visual inspections of all diesel pipelines, cable connections and switchgear will be required
every six months and servicing will be required every two years or less as per the suppliers’
recommendations;
Regular service intervals need to be scheduled for the air filters belonging to the Rotary UPS
ventilation system.
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6.2.1. POWER.GRID – Upgrade to Grid Power
The INFRA SA Consortium has analysed the power and data rack requirements as defined in [AD 1] –
SKA1 Baseline Design. Further modelling has been undertaken by the Consortium in consultation with other Consortia and two options have been considered for the provision of bulk power to the SKA site,
namely:
Option 1: Upgrade of the Eskom grid power network (Total load of 7 981.6kVA excluding the
antennas in the spiral arms) by:
Introducing 400kV/132kV transformation at the existing Eskom Kronos substation;
Providing new 400kV / 132kV (2 x 250MVA) transformer bays to the existing Kronos
substation;
Power will be transmitted by a newly constructed 132kV power line from the Kronos
substation to the newly proposed 132/33kV Astronomy substation located approximately
35km from the site.
Option 2: Utilisation of the existing bulk grid power supply to site (Total load of 4 857kVA with a
power factor of 0.98) and:
Replacing the existing 100A voltage boosters with new 200A units and repositioning the new
units;
Upgrading the 33kV/22kV Transformers from 2.5MVA to 5MVA.
It should be noted that the definition of requirements (power, cooling and number of racks) from
other Consortia will be a key activity during Stage 1 as the biggest cost-driver for SKA1 is related to
the provision of grid power to the site.
POWER.GRID Installation standards
Additions to the Substations and Grid line will be designed and installed to fully comply with the latest editions of all relevant South African National and selected international standards, as well as
regulations, codes of practise and guidelines, which will also form the basis of testing and acceptance.
Of these, the most relevant documentation will be:
SANS 10198-8:2007 The selection, handling and installation of electric Power cables of rating not exceeding 33kV (Part 8: Cable Laying and Installation)
SANS 62271-100 Circuit Breakers (1kV – 52kV)
SANS 1063 Earth Rods
SANS 1411-1 Earth Wire (Conductors)
SANS 10400 South African Occupational Health and Safety Act, Act No 1993 and regulations
6.2.2. POWER.RETC – Upgrade to Electrical Reticulation (MV and LV)
Losberg Site Complex
As per the SKA1 Baseline Design, it is estimated that the total power requirement at the Losberg Site
Complex is 4.3MVA. Calculations of the total number of processor racks required for both MeerKAT and SKA1 amount to 316 racks. In order to respond to the SKA1 Baseline Design, Option 1 is
considered:
Option 1: Utilisation of the existing Karoo Array Processor building at the Losberg Site Complex and the provision of new SKA1 Container Shed housing RFI-shielded containers to accommodate the
additional processor racks. This solution is proposed in an effort to minimise capital costs for SKA1 as an interim solution until the Science Data Processor Centre is constructed for SKA2. A further
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assumption has been made that the RFI-shielded containers will be supplied by the pulsar timing group. In addition to the above, the INFRA SA Consortium has deviated from the SKA1 Baseline
Design by assuming that the data processing will take place on site as opposed to Cape Town. The reasoning for this deviation is explained in Section 6.5.4. Should the proposed container option not be
considered feasible by the SKAO, the alternative option will be to construct a new building at the
proposed “Astronomy Complex” where the 132kV/33KV substation will be constructed (should this be required). This option has not been costed in response to the RfP.
Option 2: The INFRA SA Consortium has done further modelling on the SKA1 Baseline Design where the proposed updated SKA1 requirement was identified to be 106 processor racks in total. Based on
this modelling, the total number of processor racks for MeerKAT and SKA1 can be accommodated in
the existing Karoo Array Processor building.
For both options, the 21 Spiral Arm Antennas are supplied from existing Eskom rural overhead power
lines in the area.
Antenna Core Array Reticulation
As per the SKA1 Baseline Design, the baseline array configuration received from the SKAO was optimised by considering the local topography and EMC characteristics. Reference can be made to
[RD 6] - INFRA SA Array Layout Report in the “Reference Documents” file which forms part of this
submission.
No additional MV feeder cables will be required from the existing Power Building on site to the SKA1
antennas. The total power requirement for the SKA1 antennas is 2.8MVA.
The existing three-leg MV cable ring network provided for MeerKAT will accommodate the required
SKA1 loading requirements.
The existing on-site reticulation network will be expanded to supply the new core and outer skirt antennas with power where the MV cables will cut into the existing ring network. Most of the existing
315kVA miniature substations provided for MeerKAT can be re-used for SKA1 with some units having to be upgraded to 500kVA.
21 Antennas on the spiral arms with be supplied by existing Eskom rural overhead power lines.
It should be noted that the optic fibre design will need to be aligned with the existing MeerKAT and proposed SKA1 electrical reticulation design.
Existing Construction Camps Power Supply
The existing power and back-up supply to the Meys Dam and Losberg construction camps will be re-
used for SKA1.
POWER.RETIC Installation standards
The MV cables and mini-substations of the reticulation network will be designed and installed to fully
comply with the latest editions of all relevant South African National and selected international standards, as well as regulations, codes of practise and guidelines, which will also form the basis of
testing and acceptance. Of these, the most relevant documentation will be:
SANS 1507: Electric cables with extruded solid dielectric insulation for fixed installations (300/500V to 1 900V/3 300V)
SANS 10292: Earthing of Low Voltage (LV) Distribution Systems
SANS 10198-8:2007 The selection, handling and installation of electric Power cables of rating not exceeding 33kV (Part 8: Cable Laying and Installation)
SANS 1213: Cable Glands
SANS 60529 Enclosure IP Ratings
SANS 62271-100 Circuit Breakers (1kV – 52kV)
SANS 1063 Earth Rods
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SANS 1411-1 Earth Wire (Conductors)
SANS 60439: Low voltage switchgear and control gear assemblies
SANS 10400: South African Occupational Health and Safety Act, Act No 1993 and regulations
SANS 780 Distribution Transformers
SANS 62271-202 and SANS 1029
Miniature Substations
SANS 1874 Metal – Enclosed Ring Main Units
IEC 60354:1991 Loading Guide for Oil-Immersed Transformers
SABS 156 Moulded-case circuit-breakers
SANS 1339 XLPE MV Cable
SANS 6284-3:2007 Test Method for XLPE Cables
6.2.3. POWER.KAPB – Upgrade to KAPB Power (including DRUPS)
The Power Building was designed to serve the role of a central substation / hub - a single point to which the utility (Eskom) supply can connect and from which KAT-7, PAPER and MeerKAT antennas
and ancillary loads are subsequently fed from. In addition to offering this central distribution and control feature, an arrangement of diesel Rotary uninterruptible power supplies (DRUPSs) within the
building offer continuity of supply to the MeerKAT and existing loads.
Option 1: In terms of the SKA1 Baseline Design, the total on-site power requirement is 8.7MVA, which includes the existing KAT-7, MeerKAT and SKA1 power requirements.
In order to meet the total site requirement of 8.7MVA, the following changes will be required:
Install two new 5MVA 33/22kV oil-type transformers outside the existing Power building and
remove existing 2x2,5MVA 33/22kV transformers;
Reserve the DRUPS inside the KAPB for 400V KAPB and site complex loads and install new
DRUPS auxiliary transformer to supply its ancillaries;
Install four containerized Rotary UPSs to supply the 3,4MVA to the antennas (1,25MVA units
in a 3 + N configuration, supplying at 22kV);
Install two containers containing necessary medium voltage switchgear, complete with HVAC,
fire detection, etc;
Install an additional 1,25MVA Rotary UPS inside the Power Building, to supply the 3,8MVA to
the local Losberg site loads including data centre components (thus the 400V loads).
The INFRA SA Consortium has undertaken further modelling and has presented the following
alterative option:
Option 2: Re-use the existing Power Building based on the proposed amended power requirements derived from the KAT-7 and MeerKAT experience for SKA1 (5MVA) with the following addition:
Install an additional two 1,25MVA Rotary UPS inside the provided space inside the existing
Power Building.
Maintenance considerations, reliability and availability have been discussed in terms of both options provided.
POWER.KAPB Installation standards
The equipment in and around the Power Building will be designed and installed to fully comply with the latest editions of all relevant South African National and selected international standards, as well
as regulations, codes of practise and guidelines, which will also form the basis of testing and acceptance. Of these, the most relevant documentation will be:
Occupational Health and Safety Act 85 of 1993
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SANS 10142-1 (The wiring of premises)
IEC 88528-11 (Rotary uninterruptible systems).
Specific tests that will be performed include:
Check and confirm the integrity of control, signal and power wiring and terminations (visual
inspection, insulation tests, etc.);
Perform “cold” commissioning (functional checks, secondary relay injection, pressure testing,
phasing and insulation tests of incomer and feeder cables etc.);
Perform “hot” commissioning (functional testing of all breakers and interlocks after mains
energizing), simulating all possible modes of operation;
Airflow test report on the UPS ventilation system;
Sound pressure level measurements to ensure regulatory compliance.
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6.3. SKA.TEL.INFRA-SA.ACC – Infrastructure Access
6.3.1. ACC.PROV – Provincial Road from Carnarvon to Site
Functional Description of Element
The provincial access road to the core is currently a gravel road which has a high standard vertical and horizontal alignment as well as a 1 in 10 year return drainage design standard. It is intended to
upgrade the gravel road to a surfaced standard. The length of the road is 80km.
It should be noted that several of the outer stations will be accessed to a certain extent by the existing provincial and district low order gravel roads. These existing roads, (approximate length of
133km) may need to be repaired in places to provide better access, however this will be assessed during Stage 1.
Design Specification and Design Standards
The anticipated pavement design for the upgrade of the provincial access road is as follows:
The following was used for a preliminary pavement design:
2013 traffic 105 vehicles per day;
Directional split 50%;
Heavy vehicles 30%;
Allowance for 25 200 construction vehicles with 12 500 kg load each (315 000 tons of material
transported over the road);
Design life 20 years.
Using a sensitivity analysis with traffic growth between 1 and 4.5 % and E80 per heavy vehicle factor
of 2 to 3.75, an ES1 (0.3 – 1 million E80’s) pavement will be required. Assuming the use of locally
available granular material the following design is proposed:
13.2/6.7 Double seal with modified binder (SE-1, SBR);
125 C3 base using imported material from borrow pits (modified with 1.5% lime and 3%
cement);
150 in situ C4 using existing wearing course (modified with 1.5% lime and stabilized with 2%
cement).
Design Assumptions
As-built information will be used for the design of the upgrade to the provincial road.
Traffic loading on the provincial road is assumed to be 0.3 – 1 million E80’s with allowance for 25 000
heavy construction vehicles;
Maintenance Requirements
The provincial road to site needs to be maintained on a regular basis. Best practice maintenance could
possibly comprise the following actions:
Year 5 – Reseal
Year 10 – Asphalt surfacing
Year 15 – Reseal
Ad Hoc drainage clearing when required.
Ad Hoc pothole repairs.
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Material Required
A minimum of 6 borrow pits will be required (at approximately 28 000 m3 per borrow pit) for the
upgrade of the provincial road. These will need to be investigated and sourced as part of the site characterisation studies which is outside the scope of the Infrastructure and Power element design.
All new borrow pits will require the necessary mineral permits.
Identification of Technical Risks and Mitigation Strategy
Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register which defines the
technical risks and proposed mitigation measures.
Capital, Operational and Maintenance Costs
Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown Structure for the
detailed capital, operational and maintenance costs for this sub-element.
6.3.2. ACC.AP – Basic Farm Roads to SKA1 Antennas
Functional Description of Element
Reference can be made to [AD 1] - SKA1 Baseline Design which indicates that the SKA1 roads must be the same as the MeerKAT roads (basic farm roads).
As per the SKA1 Baseline Design, the baseline array configuration received from the SKAO was optimised by considering the local topography and EMC characteristics. Reference can be made to
[RD 6] - INFRA SA Array Layout Report. It is expected that the SKAO Configuration Working Group
will be refining the array configuration during Stage 1 which will be fixed (frozen) at the end of Stage 1.
The outer roads and core roads will be designed as basic farm roads with concrete drifts at critical drainage crossings. The basic farm road standard comprises clearing and grubbing of the route with a
grader and placing a 200mm compacted gravel layer on top of natural ground level. Earth cut off drains and channels cut by a grader will be used to channel storm water flow to the concrete drifts to
minimise erosion of the gravel layer. The drainage is relatively informal and basic and the level of
service is lower than that of the Provincial access road. There will be approximately 107 km of farm roads. Please refer to the road network layout drawings included as in Annexure A (Table 11).
Image 10: Typical Farm Road (existing MeerKAT road)
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All platforms at the antennas will be raised by a minimum of 300 mm. The platforms are 100mm higher than the farm roads in order to provide a suitable platform for vehicle turning movements and
to enable better stormwater management. Platform sizes have been designed to accommodate the turning circles of the existing SKA SA dish transporter and a maximum dish dimension of 15.5m. (Note
that this is an assumption).
Image 11: Typical platform around the Antenna Foundation for MeerKAT
The SKA SA has a Section 21 (c) and (i) Water Use License in terms of the National Water Act, 1998.
This license is applicable to the MeerKAT road network and any upgrades that may come about in the future on the farms Meys Dam and Losberg.
Design Specification and Design Standards
Geometry
Horizontal Design
Design speed : 40km/h
Absolute minimum design speed : Crawling speed
Min Radius : 80 m
Absolute minimum Radius : 24 m
Curve length : Not applicable.
Max Super-elevation : 4%
Vertical Design No vertical design standard was used on the farm roads.
Platforms
Platform radius : 24 m
Bell mouth Radius (Truck route) : 24 m
Bell mouth Radius (Maintenance route) : 5 m
Cross section
Roadway width : 5 m
Minimum Cross-fall : 4%
Fill Slopes : 1:2 (With a min slope length of 3m)
Cut Slopes : 1:2
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Drainage
Earth drains and stone pitching are considered where possible erosion and flooding of platforms may
occur. Necessary erosion protection methods were also taken into consideration to minimise erosion of toe lines, inlet and outlet structures and drains along the farm roads.
Concrete drifts were used to prevent the washing away of farm roads at critical points.
Pavement
The pavement design for the farm road network comprises a 200mm wearing course placed on a
compacted in-situ roadbed.
The platform pavement consists of a 300mm wearing course.
Design Assumptions
Centre line testing is not required for the basic farm roads.
Lidar survey information will be used for the detailed design of the roads. The existing levels will be
verified by the successful contractor on site before construction commences.
The following general assumptions were made:
The farm roads will not be upgraded to surfaced roads in the future;
The platform sizes are kept the same as the MeerKAT project;
The maximum dish dimension is 15.5m;
Borehole licensing for additional boreholes will be granted by the Department of Water
Affairs;
Each borehole with a yield of more than 8m3/day will be regarded as a sustainable
construction water source;
Maintenance operations were based on proposed best practice cycles which should provide
the user with an acceptable level of service over 30 years. The SKAO can however downscale
maintenance to an acceptable level of service;
Some maintenance equipment has been procured by the SKA SA. Additional maintenance
vehicles required for SKA1 are described in Section 6.8.3.
Maintenance Requirements
Grader blading of the farm roads will be required at least once every two months during the rainy
season and re-graveling of the farm roads will be required once every 5 years. The maintenance of
the drainage will be minimal.
Material Required
There are currently four licensed borrow pits near the core site which have been used to supply gravel material to the existing MeerKAT site.
The existing borrow pits do not have sufficient material to supply SKA1 with material thus additional
borrow pit investigations will be required to source the material required. It is envisaged that at least 11 additional borrow pits (at approximately 22 000 m3 per borrow pit) will be required for the
platforms and farm roads. These will need to be investigated and sourced as part of the site characterisation studies which is outside the scope of the infrastructure and power element design.
There is an existing quarry near Carnarvon which could be made use of for the supply of stone
aggregate. This would however imply the haulage of aggregate over an 80km distance. It is proposed to investigate and source a new stone quarry closer to the proximity of the core site.
All new borrow pits and quarries will require the necessary mineral permits. This will be applied for by SKA SA.
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Identification of Technical Risks and Mitigation Strategy
Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register which defines the
technical risks and proposed mitigation measures.
Capital, Operational and Maintenance Costs
Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown Structure for the
detailed capital, operational and maintenance costs for this sub-element.
Drawing Register
Table 11: Drawing Register for Farm Roads
Drawing Number Drawing Title - Description
Roads Typical Drawings
ACC.AP-CP-0001 Typical tear drop shape platform
Roads Layout Drawings
ACC.AP-CP-0002 Farm roads locality plan
ACC.AP-CP-0003 Farm road Sheet 1 of 4
ACC.AP-CP-0004 Farm road Sheet 2 of 4
6.3.3. ACC.AS – All-Weather Landing Strip
Functional Description of Element
A landing strip is currently under construction near the MeerKAT core and is almost completed. It is assumed that the all-weather landing strip will be utilised for SKA1.
Image 12: Airstrip after priming
The position of the landing strip was determined in consultation with the SKA SA, its contracted air charter service and based on the requirements specific to the type of airfield. The landing strip is
located in a position where it does not interfere with construction vehicle traffic. The position of the
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landing strip took the original SKA Site Bid configuration (3 cores) into account with specific regard to obstacle limitation surfaces and approach and take-off paths over antennas.
The landing strip is designed to accommodate a Pilatus PC-12 (design aircraft) and similar. Based on the International Civil Aviation Organization (ICAO) classification, it is a reference code 1B aircraft.
The Pilatus PC-12 is a single engine aircraft seating 8 passengers. Its primary dimensions are:
Wing span : 16,23m
Length : 14,4m
Height : 4,27m
Maximum take-off weight : 4 500kg
The reference field length of this aircraft is 640m. This is the length of runway required for the aircraft to take off at maximum take-off weight (MTOW) at sea level, standard atmospheric conditions, still air
and zero slope.
The length of the runway is 1300m which is surfaced to allow for all-weather operations. A small apron with connecting taxiway is also provided.
The landing strip has been registered with the Civil Aviation Authority (CAA) and the SKA SA has insurance cover. This is acceptable due to the fact that the Maximum Take-off Weight (MTOW) of the
PC-12 is less than 5 700kg which is the weight at which licensing becomes compulsory. This weight restriction has to be respected by all pilots flying into the airfield since any incident at the airfield
involving an aircraft with a MTOW of more than 5700kg will in all likelihood have insurance
repercussions.
For the PC-12 aircraft, the Rescue and Fire fighting category is 3, although with minimal air traffic
movements (less than 700 movements in the busiest consecutive three months) – this could be reduced to category 2. The preferred extinguishing agent for this category is a foam meeting the
minimum performance level B, as described in ICAO Airport Services Manual. As the airfield will not be
licensed, this is an operational and safety issue which is currently the responsibility of the SKA SA.
Design Specification and Design Standards
Geometry
The properties of the landing strip site are:
Position : Threshold North-west (15): 30° 41.163'S ; 21° 27.051'E
Threshold South-east (33): 30° 41.626'S ; 21° 27.664'E
Elevation : 1 048m above mean sea level (MSL)
Reference temperature : 35°C
An apron of 35m x 60m is located at the south-eastern threshold of the runway. This position allows
for the shortest access road to the main road. The apron is of sufficient size to accommodate at least two PC-12 aircraft to be parked simultaneously and to manoeuvre in and out of the parking positions
under own power.
Design Assumptions
No Airfield Ground Lighting (AGL) is required. The landing strip will conform to the requirements for
operations in visual meteorological conditions (VMC).
No fuel storage is required at the airfield. Should this be required in the future for SKA purposes,
provision can be made.
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Maintenance Requirements
The following maintenance program is proposed:
Year 7: Year 14:
Fog spray
Repairs over 5% of the runway area (Top layer and Cape seal)
Repaint
Repairs over 5% of the runway area (Top layer)
Re-seal (Cape seal)
Repaint
Year 21: Year 28:
Fog spray
Repairs over 10% of the runway area (Top layer and Cape
seal)
Repaint
Repairs over 10% of the runway area (Top layer)
Re-seal (Cape seal)
Repaint
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6.4. SKA.TEL.INFRA-SA.WAS – Infrastructure Water and Sanitation
6.4.1. WAS.WATER – Upgrades to Water Treatment System
Available Water
There are currently 24 boreholes on the site. All 24 boreholes have been tested for MeerKAT use.
The assumption was made that only the boreholes with a yield of 8m3/day and more would be
regarded as a sustainable source of construction water. The 18 selected boreholes have a maximum
yield of 574.52 kl per day. The chemical tests indicate high fluoride and coliform levels which are a concern.
Due to the high fluoride content of the samples from the boreholes in the area, reverse osmosis systems have been installed for drinking water at the construction camps and at the Site Complex.
Due to the high coliform content of the samples from the boreholes in the area, all water at the
construction camps is chlorinated by means of an in-line chlorinator.
Water Requirements
The water requirement will vary on a daily basis depending on what activities are taking place on site. The different phases of construction will also require different amounts of water i.e. the construction
of roads will require less water than the construction of the concrete antenna foundations. It is recommended to programme the works in such a way that the roads and foundations are not
constructed simultaneously to reduce daily water demand. A high level daily peak estimate has been
made based on calculations done for the MeerKAT project. This is indicated in Table 12.
Table 12: Daily Water Demand
Location/Activity
Daily
Demand
(kℓ)
Daily
Peak
(kℓ)
Comment
Site Complex 7 7 5000ℓ for air conditioning plus 1800ℓ for site complex
Meys Dam Camp 12 12 Allow for 50% more that MeerKAT demand
Losberg Camp 30 30 Allow for 50% more that MeerKAT demand
Road Construction 120 Assume maximum production of 1000m³ per day, 10% moisture per m3
plus 20% losses and contingency
Concrete Works 485 485 Assume maximum production of 800m³ per day, 550ℓ per m³ plus 10%
losses
Construction Dust Control 100 100 Based on 20km haul route per day
Road Maintenance 120 Allow for 100% more that MeerKAT demand
TOTAL 634
The current maximum delivery of boreholes is estimated at 570kl/day. The minimum daily demand is roughly estimated at 630kl/day. There is thus a shortfall of water supply. Water supply is further
dependent on the rain season and can vary from year to year. Additional boreholes will be required to
ensure sufficient water supply.
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Functional Description of Element (Water at Construction Camps)
There are currently two existing construction camps at Meys Dam and Losberg. As per the SKA1
Baseline Design, both construction camps will be utilised for SKA1.
Water supply is provided from a borehole, pumped to a storage tank and boosted by an in-line
booster pump to supply points at both camps. Drinking water is treated before use to conform to
standards for continued potable use. Water used for washing/bathing purposes is chlorinated to reduce the risk of bacteria in the water due to the uncertainty of water quality. The water supply
system will be upgraded for SKA1 by means of additional boreholes, storage tanks and additional reverse osmosis capacity.
Meys Dam and Losberg Water Supply
The water for the Meys Dam site is supplied from two boreholes in the vicinity of the site. Additional boreholes will be provided for SKA1 which will be metered. The existing design capacity for this camp
is 80 persons. The total average annual daily demand (AADD) is 8 000 ℓ/day. Two storage tanks with a capacity of 10 000 ℓ each are provided with additional capacity planned for SKA1.
The standard water demand per person per day for drinking and cooking purposes is 20 ℓ/person/day. With allowance for 80 persons on the site a total of 1 600 ℓ/day is required to be treated by the
reverse osmosis system installed on site. The reverse osmosis system serves as a watering point for
the site with regards to potable water. Additional reverse osmosis capacity is however planned for SKA1.
The water for the Losberg site is supplied from a borehole in the vicinity of the site. This is however
not considered sufficient thus additional boreholes will be provided for SKA1 which will be metered.
The existing design capacity of this Construction Camp is 150 persons. Considering a water demand
of 100ℓ/person/day and an emergency storage for 48 hours, a total demand of 15 000 ℓ/day for
domestic use is obtained. A washing bay for concrete trucks requires about 300 ℓ/truck/day which
equates to 5 000 ℓ/day for the washing of the concrete trucks (a total of about 15 trucks.) Total
storage is therefore for 35 000 ℓ/day. The total average annual daily demand (AADD) is 20 000 ℓ/day.
Provision is made for three storage tanks of 10 000 ℓ each and one tank of 5 000 ℓ. Additional
capacity is planned for SKA1.
With allowance for 150 persons on the site a total of 3 000 ℓ/day is required to be treated by the
reverse osmosis system installed on site.
Bacterial tests done on the water indicate high coliform counts, therefore borehole water is
chlorinated with an in-line chlorinator to reduce the possible effects of bacteria in the water.
For both sites a booster pump and pressure vessel (bladder tank) is incorporated after the storage tanks in order to provide sufficient pressure to the site. The booster pump unit is situated in the
chlorination building. As per the Department of Water Affairs requirements, water meters are installed at each borehole to measure the daily total usage of all boreholes on site. This will be monitored by
the Department to ensure that the daily water usage as approved in the Water Use License for the
site will not be exceeded.
Design Assumptions
Meys Dam
The boreholes must sustain at least 8 kℓ/day for the time span of the camp. Additional capacity will be
provided for SKA1.
Losberg
The boreholes must sustain at least 20 kℓ/day for the time span of the camp. Additional capacity will
be provided for SKA1.
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Maintenance Requirements
The following maintenance requirements are envisaged:
Boreholes
Periodic maintenance should take place at boreholes with regard to operation, cleaning of
screens, water level of the borehole, general observations, electrical components etc. Proper
maintenance and checking should prevent unnecessary standing time or dis-functionality due
to components malfunctioning.
Reverse osmosis plant
Replace filters on an annual basis.
Chlorination plant
Daily checking of liquid chlorine mix quantity.
Daily checking of electrical components functionality and general observations with regard to
all components.
Identification of Technical Risks and Mitigation Strategy
Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register which defines the technical risks and proposed mitigation measures.
Capital, Operational and Maintenance Costs
Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown Structure for the detailed capital, operational and maintenance costs for this sub-element.
Functional Description of element (Water Treatment Plant at the Site Complex)
Water supply at the Losberg Site Complex is provided from two boreholes, pumped to a storage tank
and boosted by an in-line booster pump, chlorinated by in-line chlorination and then distributed to
supply points and to the reverse osmosis system. Drinking water is treated by reverse osmosis before use to conform to standards for continued potable use. Water used for washing/bathing purposes is
also chlorinated.
Design Specification and Design Standards
Water supply at the Site Complex is provided from two boreholes, pumped to a storage tank and
boosted by an in-line booster pump to supply points. Water used for washing/bathing purposes is chlorinated to reduce the possible effects of bacteria in the water.
Allowance was made for 15 persons. The total average annual daily demand (AADD) is 6 500 ℓ/day.
Two existing storage tanks of 10 kℓ each will serve as storage for the site. Keeping in mind that the
air-conditioning units will not be filled on a daily basis, the two 10 kℓ tanks will be sufficient.
A booster pump and pressure vessel (bladder tank) are incorporated after the storage tanks in order
to provide sufficient pressure to the site.
Water for showers or sanitation purposes is chlorinated. The system supplies water to required positions as determined on site.
The standard water demand per person per day for drinking and cooking purposes is 20 ℓ/person/day. With 15 persons on the site, a total of 300 ℓ/day is required to be treated by a reverse osmosis system
installed on site.
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Design Assumptions
The borehole must supply at least 6.5 kℓ/day or 271 ℓ/h for a 24 hour cycle.
Maintenance Requirements
The following maintenance requirements are envisaged (see Table 13):
Table 13: Maintenance requirements
Reverse osmosis plant
Replace filters on an annual basis.
Chlorination plant
Daily checking of liquid chlorine mix quantity.
Daily checking of electrical components functionality and general observations with regard to all
components.
Identification of Technical Risks and Mitigation Strategy
Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register for detailed technical
risks and proposed mitigation measures for this sub-element.
Capital, Operational and Maintenance Costs
Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown Structure for a
breakdown of the capital, operational and maintenance costs for this sub-element.
6.4.2. WAS.WASTE – Upgrades to Waste Water Systems
Sanitation comprises of a package treatment plant. The package treatment plant capacity will be
increased to allow for additional loading.
Meys Dam and Losberg Construction Camp Sanitation
Considering the maximum water demand for domestic use as calculated above, the assumption can be made that the maximum sewage inflow per day will not exceed the water demand. The maximum
effluent which can be generated on the Meys Dam site is 8 000 ℓ/day and on the Losberg site is
15 000 ℓ/day. It is however envisaged to increase the capacity of the existing package treatment plants for SKA1.
A central main sewer line is positioned on the sites. Connection points are constructed at regular intervals to enable sanitation services to be supplied to park home units. Due to the flat gradients
present, a sewer pump sump is provided before the package treatment plant.
An on-site package treatment plant is installed on the sites. The treated effluent from the package treatment plant is discharged into an evaporation bed, formed by a berm on the downstream side of
the package treatment plant. The SKA SA has waste management licenses for these treatment package plants.
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Image 13: Meys Dam sewer package treatment plant
Image 14: Losberg Construction Camp sewer package treatment plant
Maintenance Requirements
The following maintenance requirements are envisaged:
Sewer package treatment plant
The operations and maintenance procedures will vary depending on the make (brand) of treatment
plant provided by the contractor. In general the following are deemed good practice procedures (see
Table 14):
Table 14: Operations and maintenance good practice procedures
Weekly
Replace chlorine tablets in chlorine contactor – AWW 20-25 SPA Tabs Stabilised, containing
Trichloroisocyanuric acid
Monthly
Take samples of incoming and final effluent (from chlorine contact tank) and dispatch to a Laboratory
for analysis and report.
Yearly
Check level of contamination and solidification in pre-digestion and purge if necessary.
Every 30 000 Hours (3.5 Years)
Replace diaphragms in air blowers
Identification of Technical Risks and Mitigation Strategy
Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register which defines the
technical risks and proposed mitigation measures.
Capital, Operational and Maintenance Costs
Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown Structure for the
detailed capital, operational and maintenance costs for this sub-element.
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6.5. SKA.TEL.INFRA-SA.BLDS – Infrastructure Buildings
6.5.1. BLDS.SBASE – Klerefontein Support Base (all buildings)
Design description of the new MeerKAT offices, workshops and stores constructed for MeerKAT
As per the SKA1 Baseline Design, an assumption was made that the buildings located at the
Klerefontein Support Base will be utilised for SKA1. A draft CON OPS document is still under
development and the Logistic Support Analysis as defined in Reference Document [RD 3] – INFRA SA Integrated Logistic Support Proposal (ILS) still needs to be developed as part of Stage 1. This will
define the logistical support, resources, spares and equipment that will be required for SKA1 which might have an impact on the decision to utilise the existing facilities at the Klerefontein Support Base.
It might become evident during Stage 1 that there are insufficient support facilities at Klerefontein
(e.g. office space for support staff) and provision for additional facilities might have to be reconsidered.
The Klerefontein Support Base workshops and offices are located north-east of the existing Klerefontein Farm house.
Entry to the buildings could either be from the west (parking area) or the south (delivery yard). The storage area (200m²) is located to the east of the “building complex” with access (roller shutter
doors) to the south and west. The workshops are to the north of the building complex with access
from the south.
The design of this facility aims to utilize passive cooling as much as possible, firstly, in the storage and
workshop areas (with a higher volume) by means of a ventilated roof and secondly, by using thermal mass on the western façade (dry pack stone walls) to prevent the harsh western sun from heating the
building during the day. The introduction of a courtyard also aids the cooling of the building, together
with narrow floor plates and adequate cross-ventilation. The office has a double-roof system, which aids the passive cooling of the human interface areas to a great extent.
Key Components
A clean room of 20m2 has been included inside the electronic workshop that complies to US FED STD
209E Class 100 000 clean room (ISO 14644-1 standard ISO 8 Equivalent).
Image 15: Klerefontein Workshops, office and stores constructed for MeerKAT
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Image 16: Klerefontein Workshops, office and stores
Figure 5: Klerefontein support base workshop plan
6.5.2. BLDS.SPLEX - Site Complex (Site, Dish Shed, Pedestal Shed, Accommodation, Security, KAT-7 Shed, Diesel)
Dish Assembly Shed Extension – design description
In terms of the SKA1 Baseline Design, an assumption was made that the existing Dish Assembly Shed
will be utilised for SKA1.
The footprint of the Dish Assembly Shed Extension is designed with the indicative sizes of the dish
moulds and specific dish manufacturing process taken into consideration for KAT-7 and MerrKAT.
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Specific door clearance widths and crane heights were required for the manufacturing of the KAT-7 and MeerKAT Antenna Positioners. The existing structure has been altered slightly to meet these
requirements.
Different equipment / material stores are included in the building and each store has its own roller
shutter door.
The Dish Assembly Shed is fitted with two 10 ton overhead gantry cranes with a hook height of 8.1m.
In order to maximise space within the Dish Assembly Shed, both sets of access doors are configured
in order to allow maximum entrance in to the shed.
In order to minimise RFI emissions from the sheds, specific policies have been implemented for the
electrical wiring, lights and network connections. Earthing, bonding and lightning protection is
provided to protect the building against lightning strikes.
General purpose socket outlets are provided for daily operations.
Refer to Annexure A for the Losberg Site Complex Layout and the Dish Assembly Shed Plan
Pedestal Integration Shed – design description
In terms of the SKA1 Baseline Design, an assumption was made that the Pedestal Integration Shed will be utilised for SKA1.
The Pedestal Integration Shed is located opposite (to the north of) the Dish Assembly Shed, with a
loading / marshalling yard between the two buildings. The footprint is sufficient for the manufacturing of the pedestal component of the MeerKAT Antenna Positioners as well as the lifting and tilting
thereof.
The Pedestal Integration Shed is fitted with a 10 ton overhead crane with a maximum hook height of
12m.
A lean to office has been provided at the rear of the building.
The Pedestal Integration Shed is fitted with the same door configuration as that of the Dish Assembly
Shed extension, thus maximising the entrance and exit space.
In order to minimise RFI emissions from the sheds specific policies have been implemented for the
electrical wiring, lights and network connections. Earthing, bonding and lightning protection is
provided to protect the building against lightning strikes
General purpose socket outlets are provided for daily operations.
Refer to Annexure A for the Pedestal Integration Building Plan.
Image 17: The Losberg Site Complex with Dish Assembly Shed and Pedestal Integration Shed on the left
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6.5.3. BLDS.KAPB - Upgrade to Karoo Array Processor Building
Overview of description
As indicated earlier in this report, the INFRA SA Consortium has deviated from the SKA1 Baseline
Design by assuming that the data processing will take place on site as opposed to Cape Town.
Reference can be made to Section 6.2 (SKA.TEL.INFRA-SA.POWER – which describes the two options
considered for the KAPB in terms of power) and is summarised as follows:
Option 1 (SKA Baseline Design): Utilisation of the existing Karoo Array Processor Building
and the provision of a new SKA1 Container Shed housing RFI-shielded containers to
accommodate additional processor racks.
The existing Karoo Array Processor Building was designed to accommodate 135 processor
racks. A total of 316 processor racks are required for MeerKAT and SKA1 in terms of the SKA1 Baseline Design.
In order to cater for additional racks required for SKA1 while minimising capital cost, it has been recommended that the additional racks be housed in RFI-shielded containers for SKA1
as an interim solution until the Science Data Processor Centre is constructed for SKA2. The
RFI-shielded containers will be housed in a Container Shed (described in Section 6.5.4).
This will entail housing an additional 184 racks in the RFI-shielded containers. Each unit will
be provided with its own HVAC system.
Should the proposed container option not be considered feasible by the SKAO, the alternative
option will be to construct a new building at the proposed “Astronomy Complex” where the
132kV/33KV substation will be constructed (should this be required) which is required in terms of the SKA1 Baseline Design. This option has however not been costed in response to
the RfP.
Option 2 (Optimised option): Utilisation of the existing Karoo Array Processor Building.
The existing Karoo Array Processor building was designed to accommodate 135 processor racks, whereas the proposed updated SKA1 requirement (as part of the SKA SA modelling and
optimisation studies that were undertaken) was identified to be 106 racks in total.
This implies that all the racks for SKA1 can be accommodated in the existing building.
A description of both options is described below.
Option 1 and Option 2
The Karoo Array Processor Building (KAPB) is located on the Losberg Site Complex North-East from
the Dish Assembly Shed. Its position respects the geometry of the existing buildings on the site and is determined by the two main access areas within the building, the delivery area on the west of the
building and the public entrance on the south. The public entrance aligns with a natural central visual
axis that originates at the top of the Losberg Hill.
The building is a buried bunker constructed from concrete retaining walls with soil abutting the walls.
This type of construction has been used for various reasons including thermal performance of the building (keeping external temperature fluctuations to a minimum), RFI shielding advantages (the fact
that the building is buried contributes to the overall RFI shielding) and acknowledging the natural
Karoo landscape.
The building footprint of KAPB consists of four areas:
RFI-screened Data Rack Room
This area houses all the data processor racks and the Maser room. It has a raised access floor area designed to carry the weight of the racks and prevent static interference. This floor was
raised 850mm from the structural floor level, to allow for all services in the void. The Data Rack Room allows for 135 racks.
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Some services run below the floor (power and cooling air) and some services above in racks, i.e. trays for fibre cables, lights, fire detection and fire suppression
Drop-in central passage which links to the Power facility.
The western end of the passage is completely open to allow the dropping-in of equipment with mobile cranes. A 1 ton Jib crane has been provided to assist with the lifting and
unloading of smaller equipment.
Service area
Located east of the RFI-screened Data Rack Room and north of the central drop-in passage, this area contains the HVAC plant and is also the area where the cables, fibres, pipes and air
penetrate the RFI-shielded room. Its structural floor level is 680mm lower than the surrounding areas in order for services to penetrate the Data Rack Room in the void of the
access floor.
KAPB ancillaries area
It includes a laboratory, control room, ablution facilities, store room, an Optic Fibre
Distribution Room and an open courtyard.
The Self weight of the RFI Shielding was taken into account during the design. The structural steel inside the walls and roof of the building are galvanically bonded to the earthing system
in order to provide additional RFI screening.
Electrical and Electronic Engineering
General Electrical Installation
The LV supply inside the building is fed from the Rotary UPS. Attention was given to the design of the cable routes, earthing and bonding in the building which has been designed to minimise RFI
emissions.
A dual redundant power distribution system is used to supply power to the Karoo Array Processor
(KAP) racks. An A and B reticulation system is installed, consisting of dual distribution boards feeding
the racks.
Air conditioning units in the Data Rack Room are also supplied from a dual redundant power
distribution system with manual transfer switches to allow maintenance to the equipment without any disruptions.
All metal cables feeding the Data Rack Room penetrate the RFI shielding through RFI filters.
Fibre cables penetrate the RFI shielding through special waveguide penetrations
Lighting inside the building is by means of LED luminaires, which have been tested to ensure that they
emit minimal RFI.
Extensive earthing, bonding and lightning protection is provided to limit RFI and to protect the
building against direct lightning strikes. The following were provided:
Earth mat and outside ring trench earth conductor with earth rods;
Earth bars in cable trenches;
Earthing of cables entering and exiting the building;
Additional bonding of re-enforcing structural steel in columns, structural walls and floor
screeds;
Lightning down conductors.
Fire detection and gas suppression system
An early warning smoke and heat detection system is installed in all the power areas of the KAPB.
This consists of ceiling mounted heat and smoke detectors as well as an aspirating system in the
processor room, linked to the fire panel.
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A gas extinguishing system is installed in the Data Rack Room and low voltage plant room and consists of gas bottles with distribution piping. The gas extinguishing system is activated by the
smoke detection system.
Access control
Electronic access control is installed at the entrance doors to the KAPB and the entrance to the Data
Rack Room, the optic fibre distribution room and the MV electrical areas.
CCTV cameras are installed to monitor all the network connection areas as well as the MV electrical
control areas.
Mechanical Engineering
Air conditioning and ventilation are provided for the following requirements:
Process
Comfort
Fresh air for the occupants of the building
Data Rack Room – process requirements
The Data Rack Room is an area where all the computing, data management and data transmission equipment is housed. The components are housed in standard 19” racks. Since the components
generate heat, a heat rejection strategy has been developed to maintain all the components at acceptable temperatures. Racks are equipped with heat rejection fans which blow to the back of the
rack. By grouping the racks, a cold aisle and a hot aisle was formed, which provides optimum cooling
for the racks and the components in the racks.
A ceiling void has been provided to optimise the return of hot air to the CRAC units. The chimney
concept can be used for racks with high heat density. The below information provides an indication of the range of cooling concepts for the racks:
The design is based on average of 5kW per rack to 8kW per rack the hot aisle / cold aisle concept is
applicable.
8kw to 20 kW requires special racks with chimneys linking to the ceiling void;
Above 20kW will require special in rack cooling solutions.
As the room is shielded with a radio frequency electromagnetic shield, the penetrations through the shield were kept as small as possible. An air-cooled down-blow computer type air conditioning system
was the most suitable system to be utilised.
Filtered fresh air to overpressure and provide clean air was provided for the Data Rack Room. The
over pressurization minimises the ingress of dust.
For the additional SKA1 racks, modular air conditioning units will be expanded in the KAPB.
For the MeerKAT project six (n+1) modular units are installed. The facility can accommodate eleven
units in total. The total cooling capacity for the eleven units is 640kW.
Fire and Wet Services
Fire Services
The following Fire Protection measures were provided for this building:
One hour fire rated separation for Data Rack Room, A/C Plant Room and Store Room.
Two hour fire-rated separation between the KAPB and Power Building portions of the building
are by means of fire walls and a fire-rated shutter linked to the fire detection system. The
shutter is normally open and only to be closed in case of activation of the fire detection
system and/or power failure to the shutter.
Two separate and remote means of escape from building.
Fire detection and alarm system throughout as described under Electronic Services section.
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Automatic gas extinguishing to Data Rack Room as described under Electronic Services
section.
Portable carbon dioxide and dry chemical powder type fire extinguishers.
Rain and Condensate Drainage Installation
Rainwater entering the areas open to the atmosphere (open courtyard), are drained into floor drains
and channels. These floor drains and channels drain by gravity into an underground collection sump.
Condensate from the air handling units is drained by gravity into the same sump. The sump is fitted with a cast iron cover and frame and will house a duplicate submersible pump set (duty plus standby),
with the necessary lifting chains, isolation valves and non-return valves. Water is pumped from the underground sump into the site storm water drainage system.
The pump operation is automatically controlled by means of an electrical control panel and float
switches. Any fault will activate an alarm condition.
Sanitary Drainage Installation
Soil and waste from the sanitary fittings is drained by gravity into an underground collection sump, situated inside the services shaft.
The sump is fitted with a cast iron cover and frame and will house a duplicate macerator type submersible pump set (duty plus standby), with the necessary lifting chains, isolation valves and non-
return valves. Water is pumped from the underground sump into the site sewer reticulation system.
The pump operation is automatically controlled by means of an electrical control panel and float switches. Any fault will activate an alarm condition.
Radio Frequency Interference (RFI)
The management of RFI is critical for the successful operation of MeerKAT and the SKA and consists
of carefully chosen electrical components, the management of stray currents, operation, screening RFI
generating equipment, etc.
The Karoo Array Processor Building (KAPB) contains a large number of computer systems that
generate high levels of RFI and therefore the following approaches were followed to limit the RFI emissions:
The location behind Losberg assists with the screening and a special RFI berm (Nuweberg) has been
constructed from all the excavated soil.
This assists by not having a direct line of sight (LOS) to any telescope antenna.
The KAPB is mostly below ground level allowing the surrounding soil to absorb RFI emissions;
The Data Rack Room and laboratory is fully screened with electromagnetic shielding
consisting of treated steel panels;
Electromagnetic shielding has been installed as per Table 15:
Table 15: Electromagnetic shielding
Shielding Effectiveness of shield room Frequency: (f) Required value
Electrical field 70 Mhz < = f < 10 Ghz 100 dB min
Microwave field 10 Ghz < = f < 15 Ghz 80 dB min
Extensive earthing and bonding of reinforcing, cables, supports, etc.;
Careful planning of routes for conductive cables. In trenches below the floor level with
attention to earthing and bonding of the trenches
Berms were constructed to limit RFI emissions in the direction of the antennas;
RFI penetrations including RFI filters for metal cables, Waveguide penetrations for fibre
cables, special pipe penetrations and honeycomb filters for air
Double access doors to the Data Rack Room and Lab and Control room area.
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Power Building – description and key components
The Power Building is located on the Losberg Site Complex North-East from the Dish Assembly Shed.
The building is a buried bunker constructed from concrete retaining walls with the soil abutting the walls. This type of construction was proposed for various reasons including thermal performance of
the building (keeping external temperature fluctuations to a minimum), RFI shielding advantages (the
fact that the building is buried contributes to the overall RFI shielding) and respecting the natural Karoo landscape.
Image 18: Karoo array processor building and power building
The building footprint of the Power Building consists of four areas:
Drop-in central passage which links to the KAPB on the west
The western end of this passage is completely open to allow the dropping-in of equipment
with mobile cranes and the use of the 1 ton Jib crane.
Power Building Control Room
Located north of the central passage and east of the service area of the KAPB.
Power Building Equipment
Located north of the central passage and east of the Power Building control area. This is where the Rotary UPS’s, generators and day tanks are located. This area has two ventilation
shafts: Intake and Exhaust shafts.
Power Building Transformer / Switch gear area
Located south of the central passage. Adequate ventilation was provided for in this area.
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Figure 6: KAPB Basement Plan
Electrical Engineering
Reference can be made to Section 6.2.3 SKA.TEL.INFRA-SA.POWER where the electrical design has
been described in detail.
Mechanical Engineering
The transformer room is ventilated to limit the temperature in the room to 40 ⁰C.
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Fire Services
The following Fire Protection measures were provided for this building:
One hour fire rated separation for the Power Control Room.
Two hour fire rated separation between the Power Building and the KAPB portion of the
building by means of fire walls and a fire rated shutter linked to the fire detection system. The
shutter will be normally open and only to be closed in case of activation of the fire detection
system and/or power failure to the shutter.
Single means of escape from the building.
Fire detection and alarm system throughout as described under Electronic Services section for
the KAPB.
Automatic gas extinguishing to the Control Room as described under Electronic Services
section for the KAPB.
Portable carbon dioxide and dry chemical powder type fire extinguishers.
Wet Services
There are no sanitary fittings that require water supply or drainage in the Power Building portion of this building. The underground services trenches were provided with floor drains with backflow stops
to drain any ground water that might enter these trenches. These are drained by gravity to into the
rain and condensate drainage sump.
6.5.4. BLDS.CSHED - SKA1 Container Shed
As described in Section 6.5.3, two options were investigated with regards to housing the additional
data processing racks for SKA1. This section describes Option 1 (as per the SKA1 Baseline Design) - Utilisation of the existing Karoo Array Processor Building and the provision of a new SKA1 Container
Shed housing RFI-shielded containers to accommodate additional racks.
In order to cater for additional racks required for SKA1 while minimising capital costs, it is
recommended that the additional racks be housed in RFI-shielded containers for SKA1 as an interim solution until the Science Data Processor Centre is constructed for SKA2. The RFI-shielded containers
will be housed under a Container Canopy (described in this section below).
This will entail housing an additional 184 racks in the RFI-shielded containers. Each unit will be provided with its own HVAC system. The total number of containers will still need to be confirmed due
to the different suppliers and size of containers available.
Description of work to be done
Two 22.5m x 12m RFI-shielded rooms (to be provided by the telescope element, but will be agreed in
Stage 2) will be housed in a Container Shed for SKA1. Each RFI-shielded room can house up to 96 racks and are made up of five 4.5m x 12m containers. See Figure 7 for proposed layout.
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Figure 7: Proposed container layout
For the SKA1 RFI-shielded containers, a concrete surface bed will be provided. This surface bed will
be constructed on a prepared civil earthworks platform. In order to protect the containers from the natural elements a lightweight steel canopy will be provided over.
To assist with cable routing, a maintenance tunnel has been provided that runs the entire length of
the containers and connects to the KAPB wall on the northern side. Access to the tunnel is via a staircase house. Earth excavated from the tunnel will be stockpiled onto Nuweberg.
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Figure 8: Proposed location of Data Containers to the North West of the KAPB
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Figure 9: Showing plan of cable tunnel and staircase housing
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Figure 10: Showing section through containers, steel canopy, staircase & cable tunnel
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Identification of Technical Risks and Mitigation Measures
Reference can be made to Reference Document [RD 2] –INFRA SA Risk Register where technical risks and proposed mitigation measures are described for this sub-element.
Capital, Operational and Maintenance Costs
Reference can be made to Reference Document [RD 1] - INFRA SA Cost Breakdown Structure for the breakdown of capital, operational and maintenance costs for this sub-element.
6.5.5. BLDS.CCAMP - Construction Camps (Losberg and Meys Dam) – existing)
Functional Description of Element
There are currently two existing construction camps at Meys Dam and Losberg which will be used for SKA. The provision of power to the camps has been described under Section 0
above and the provision of water and sanitation under Section 0 above. It is envisaged that
only the water and sewerage network at both camps will be upgraded for SKA1 as defined in the Water and Sanitation Section above.
Meys Dam
The SKA SA project will be utilizing the Meys Dam Construction Camp for the following:
Accommodation for contractors (porta cabin-type accommodation to be supplied by
the respective contractors);
The Meys Dam farmhouse has been converted by the SKA SA into office space for
SKA staff and contractors.
The site is levelled and gravelled with a 150mm wearing course.
A 3m high berm, for RFI screening, that will surround the Meys Dam camp site is also
proposed.
Image 19: Meys Dam Construction Camp
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Losberg
The Losberg Construction Camp is utilised for the following:
Accommodation for contractors The Losberg farmhouse has been converted by the
SKA SA into office space for use by contractors.
The site is levelled and gravelled with a 150mm wearing course.
Image 20: Losberg Construction Camp
Environmental considerations
Waste management and other environmental considerations will be handled as part of the EIA process and in accordance with the approved environmental management plan which will
be contractually enforced. The contractor will be responsible for all waste management on
the site. All waste must be disposed at the licensed dump site in Carnarvon. This will be monitored and enforced by the SKA SA Safety, Health and Environmental Officer.
Identification of Technical Risks and Mitigation Strategy
Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register for a
description of the technical risks and proposed mitigation measures for this sub-element.
Capital, operational and maintenance costs
Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown
Structure for a detailed breakdown of the capital, operational and maintenance costs for this sub-element.
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6.5.6. BLDS.HQ – Cape Town HQ Building
As per the SKA1 Baseline Design, an assumption has been made that office space will be
leased in Cape Town for SKA1. There are however two options available to the SKAO which include:
Option 1: Leasing office space in Cape Town
The SKA SA office is located at The Park building in Pinelands, Cape Town. The SKA SA is
presently leasing the 3rd floor (approximately 1500m2) and the 2nd floor (approximately
1500m2). Half of the 2nd floor is leased to the Vincent Palotti Hospital. This sub-lease expires in March 2014. The SKA SA is currently in discussions with Blend Properties to secure the 4th
floor (approximately 1500m2). Should this be possible, it is expected that the SKAO could possibly be accommodated with the SKA SA in this building.
Staff parking will be required at a considerable cost. The need is anticipated to be 15 open and 15 basement parking slots. It is not clear at this stage what the floor space requirement
is for SKA1 and what the timelines are for the occupation in the leased office floor space.
The estimated lease costs per square metre are included in Reference Document [RD 1] – INFRA SA Cost Breakdown Structure. It is however important that should the SKAO be
interested in this option, that this be discussed and pursued with SKA SA as soon as possible.
Option 2: New HQ Building in Cape Town
The SKA SA is currently in discussions with the Western Cape Government to investigate the
possibility of securing government-owned land in Cape Town and constructing a new building for the MeeKAT science, engineering and operations team. Greenfields land has been
identified at the Alexander Hospital in Observatory, Cape Town which is located adjacent to the South African Astronomy Observatory (SAAO). The Western Cape Government has
commenced with the administrative process of securing the land which will require the
signing of a Memorandum of Agreement between the Western Cape Government and the National Research Foundation (NRF). SKA SA is also investigating funding options for the
construction of such a building. The timelines for the construction of this building are dependent on the SKA SA funding model.
There is sufficient land available on the same site to accommodate the SKAO HQ building (SKA2 requirement). Should the SKAO be interested in pursuing this option for SKA2, the
SKAO would have to be party to the same agreement that the SKA SA will enter into with the
Western Cape Government. It is however important that should the SKAO be interested in this option, that this be discussed and pursued with SKA SA as soon as possible.
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6.6. SKA.TEL.INFR-SA.FOUND – Infrastructure Antenna Foundations
6.6.1. FOUND.MID – Foundations for SKA1-MID
The SKA1-mid telescope antennas will be a mixed array of 64 13.5m diameter antennas from the MeerKAT array and 190 new 15m SKA1 antennas. As per the SKA1 Baseline Design, the
SKA1 mid array is proposed to be centred in the same location as the MeerKAT array, and will incorporate the MeerKAT antennas as part of SKA1.
The new SKA1 Antenna Foundations (including assumptions about underlying ground
conditions, foundation types and materials) are discussed below.
Foundation Loads
Loading and performance requirements for the telescope foundations have been defined in the revised SSG loading requirements titled, New Wording for RFI Document on Foundations. Antenna foundations will need to be tailored for the sub-surface geology at each location. It is expected that the foundations can be designed to accommodate variation in ground level
and be built to withstand flooding.
The lists below contain magnitudes of forces and moments on the foundation interface, arising from a 15m diameter offset-fed antenna in operational and survival conditions.
In survival conditions, there must be no permanent displacement of the foundation. In static conditions (gravitational forces only), deflections of the foundation will be subsumed in a
pointing model. The telescope pedestal base is assumed to be a heavy circular flange on a
2.2 m diameter bolt circle.
Static Conditions
Precision Operations
Degraded Operations
Survival (in the “birdbath” position)
Wind 0 m/s 7 m/s 20 m/s 42 m/s
Overturn moment 36 kNm 80 kNm 483 kNm 1056 kNm
Down force 212 kN 220 kN 238 kN 388 kN
Side force 0 kN 8 kN 62 kN 80 kN
Maximum overturning deflection N/A 3 arcsec 36 arcsec N/A
Azimuth torque 0 kNm 5.5 kNm 40 kNm 90 kNm
Following preliminary studies, two possible founding solutions were anticipated, namely:
Pad foundations onto bedrock or competent calcrete, where the depth of this
material occurred at depths of less than 3 m,
Piled foundations (augured piles), where the depth of the competent material
occurred at depths greater than 3 m.
Refer to Annexure B for detailed Antenna foundation load solutions.
The drawing signifying the foundation solutions is attached in Annexure A:
FOUND.MID-SS-0001 – Proposed Antenna Foundation
Comments on the Foundation Loads:
We have assumed that for a pointing accuracy of 3 arc-seconds, only the wind load
should be taken into account. Other loads, e.g. those caused by the antenna own
weight should not have an impact on pointing accuracy.
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We would like to highlight that for the determination of the deflections or rotations in
the design of the foundations, un-factored loads were used, as is the norm in the
design of structural and foundation systems.
Functional description of element
The foundation system for the new SKA1 antennas is described as follows:
a. 190 scattered antenna foundations, each consisting of the following components:
i. 4 x 750 mm diameter piles per foundation;
ii. A 4 200 x 4 200 x 1 200 mm thick reinforced concrete pile cap with a 2 800
mm diameter plinth x 250 mm high;
iii. The design and fabrication of the anchor cage assembly does not form part
of the Infrastructure Package, and will be supplied by the DISH Consortium. This package will however make provision for the casting in of the assembly
cage into the concrete foundation.
iv. 1 x 110 mm diameter Kabelflex sleeve (to be provided by the SaDT Consortium) to house of 2 x 40 mm diameter fibre sleeves, cast into the pile
cap.
v. 1 x 110mm diameter Kabelflex sleeves to house the electrical cables, cast
into the pile cap;
vi. Earthing and lightning protection system;
vii. Provision for an earthworks fill platform around the foundation will be made.
Geotechnical
Refer to Annexure B for the geotechnical investigation details.
Identification of Technical Risks
Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register which describes the technical risks and proposed mitigation measures for this sub-element.
Capital, Operational and Maintenance Costs
Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown
Structure which provides a breakdown of capital costs related to this sub-element.
Additional Notes
It should be noted that some of the antenna positions may be subject to flooding as
they are located in or on the edges of river channels. The true hazard potential at
these sites would need to be reassessed by flood line studies.
Destructive pile tests (trial piles) as well as non-destructive testing of working piles
will be required in order to ensure that the piles meet their performance
requirements. It must be noted that should the Antenna Foundation Loadings
change, this could impact on the foundation design and subsequently the
construction costs. This would have to be managed via change control of the ICD.
Cable entry points have been assumed at this stage.
The length of the piles will be dictated by the soil profiles at each foundation location.
Because these profiles vary quite substantially from location to location, the
estimated costs for the piling may ultimately differ from what was estimated.
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Design Specification and Design Standards (Earthing and Lightning Protection Systems)
Similar design standards are proposed for the SKA1’s lightning protection and earthing system to that of MeerKAT.
Installation and on-site testing is required to ensure a bonded lightning protection/earthing system that conforms to the requirements of SANS 10313, 10292, 10142 , 6100-5-2; 62305
(2011); 10199 (2010).
Earthing
Soil resistivity tests must be undertaken by specialists to ensure that a good representative
value of the current soil resistivity value is obtained.
Based on the tests done for MeerKAT, it is evident that the deeper the piling for the Antenna
Foundation is installed, the better Soil Resistivity (Ω.m) values are obtained.
Design Criteria:
The maximum allowable earth resistance as measured from the dedicated earthing
terminals relative to the earth mass will not exceed the specified 1 Ω value;
Four Symmetrical 70mm² bare copper connections from the earth grid to the anchor
cage will be provided;
The maximum allowable resistance per bonding connection must be 10mΩ;
All earth connections within the earth grid to be Exothermic welded (i.e Cadweld or
Exoweld to minimise both the possibility of galvanic action or electrolysis and
ensuring connectivity and strength of the connection. Note that the exothermic
welding of different material requires special powder compounds;
Two generic earthing layout designs were done based on the 5m and 10m deep
piling method of the antenna foundation structures;
Step and Touch Potentials were evaluated as part of the proposed solution;
Ring main earth connections with deep corner electrodes were incorporated into the
design as part of minimizing the earth potential rise.
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6.7. SKA.TEL.INFRA-SA.COMMS – Infrastructure Communication Systems
No requirements have been identified in the SKA1 Baseline Design for Infrastructure Communication Systems. The INFRA SA Consortium has therefore made assumptions based
on existing knowledge on systems implemented for MeerKAT which will be expanded for
SKA1. This includes the Local Area Network sub-element, Building Management System sub-element and Communication System.
6.7.1. COMMS.LAN – Upgrade to LAN System
This section provides an overview of the LAN services implemented for MeerKAT and proposed upgrades required for SKA1.
Deployment Overview
SKA South Africa has undertaken an initiative to deploy LAN infrastructure, interfaced to the
SKA SA optic fibre backbone, to enable users to access a variety of information services through-out the Karoo Astronomy Reserve (KAR), the SKA SA Cape Town office and the SKA
SA Rosebank office (collectively referred to as the KAR LAN for the purpose of this section).
The KAR LAN is required to provide the following data services:
Scientific data (unidirectional to Cape Town);
Control and Monitoring (CAM) of telescopes;
Webcam data for telescopes;
BMS Access Control;
Voice (IP-telephony);
BMS CCTV;
BMS Data;
Video Conferencing;
Internet Access;
General data: mail, ftp, etc.
Network Authorisation depending on user roles and ID
EduRoam access.
The KAR LAN provides users with end-points at the following locations – the LAN
infrastructure interfaces to the SKA fibre backbone at nodes as indicated:
a. Karoo Astronomy Reserve;
i. Carnarvon POP (LAN interface to the SKA SA optic fibre backbone and to the long-haul fibre infrastructure linking the KAR to Cape Town);
ii. Klerefontein Support Base buildings;
iii. Losberg Site Complex (all buildings);
iv. Construction camps (both interfacing to the SKA SA optic fibre backbone via
fibre splices);
v. Losberg KAT-7 site (containers).
b. SKA Cape Town office;
c. SKA Rosebank office;
d. Remote Users (via VPN).
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A conceptual connectivity diagram of the LAN and its interface with the SKA SA backbone is
shown in Figure 11.
SKA
Pinelands
Klerefontein
LAN Core
SKA LAN
LegendLong-haul fibre
(SANReN/
Broadband Infraco/
Other)TelCo Break-out
Telkom Exchange
Pinelands
VSAT
TerminalCarnarvon
POP
TelCo Break-out
Telkom Exchange
Carnarvon
Workshop
Office
New
Workshop
C-BASS
Houses
ARC
Security
Control
Losberg
Accom./
Office
KAPB
Pedestal
Assembly Shed
Mobile
Homes
Security
Control
Dish Assembly
Shed
KAT7
Core Site
MeerKAT
Core Site
Construction
Camps
ASC/PAPER
containers
VSAT
Terminal
SKA
Rosebank
TelCo Break-out
Telkom Exchange
Rosebank
Losberg Site Complex
SKA Fibre
backbone
Future diverse
route
Hutchinson
Kronos
Figure 11: Conceptual SKA SA LAN and associated network
Technical Overview
LAN Infrastructure
The following section provides a brief overview of the nature of equipment provided as part of the LAN infrastructure which will be expanded for SKA1:
Optical Fibre Reticulation – All fibre connections between buildings on the local loop
of the KAR LAN comprise 24-core Single Mode pulled fibre direct-buried in PVC
sleeves;
In-building LAN cabling – CAT7 UTP cabling is utilised in the RFI sensitive Losberg
installations, whereas CAT6 is used elsewhere. All cabling conforms to structured
cabling standards;
Access Network Switches - A combination of 8-, 12-, 24- and 48-port Power-over-
Ethernet (PoE) Cisco Switches are deployed, comprising fibre modules for
connectivity to the fibre backbone (or to other KAR LAN switches as the case may
be). These switches ensure 1Gbps throughput at end-points;
Backbone switches - 10Gbps blade fibre switches in a chassis configuration are
located at the key interfaces to the SKA fibre backbone, namely SKA Cape Town,
Klerefontein Office and Losberg KAPB. A redundant core switch is envisaged for the
KAPB;
Network Racks - Standard 19” racks are deployed throughout, sized in accordance
with equipment volumes. Racks comprise a 500VA UPS (in areas where no site UPS is
provided), PDU (Power Distribution Unit), UTP and fibre patch panels.
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Firewall
Two 1-2Gbps throughput firewalls are located at the Carnarvon POP and the Losberg KAPB. The firewalls include the following security features:
High-performance security services, including application-aware firewall, SSL (Secure
Sockets Layer) and IPsec VPN (Virtual Private Network), IPS (Intrusion Prevention
System) with Global Correlation and guaranteed coverage, anti-virus, anti-spam, anti-
phishing, and web filtering services, and;
Delivers highly effective network-layer and application-layer security user-based
access control.
VLAN Structure
The key data roles, namely Telescope Control and Monitoring, science data, VoIP telephony, basic file handling, video conferencing, CCTV, BMS and Internet access have been segregated
by way of dedicated VLANs designated with the highest priority.
The remaining VLAN’s, designated for contractor Internet access, administration and other, have been allocated lesser priority.
Management traffic for switches runs on a separate VLAN so as not to interfere with normal day-to-day operations.
The VLAN’s are trunked to all end-point switches allowing any VLAN to be used at any location on the network.
Network Access Control
Network authentication is carried out for all users over the entire network. User roles are set up on a network authentication device/server hosted at Cape Town, with a backup replicated
authentication device/server hosted at Klerefontein. The servers cater for the variety of roles such as Science, WWW, CCTV, Administration etc.
The NAC is cross-OS (operating system), ensuring provision for multiple operating systems
such as Linux, Microsoft and Apple on the same network.
The authentication needs to cater for all users, both onsite and remote, for example VPN
users.
The VLAN structure is layered, allowing users to be dynamically assigned to a VLAN based on
their user account/role giving them flexibility of roaming anywhere on the network.
The NAC also adds additional security to ensure that no unauthorised devices/users may
connect to the network. The NAC monitors in real time who is connected to the network and
where they are currently located.
Warranty and Support
All equipment carries a standard 3 year warranty – negotiations are under way for extensions of such warranties.
Maintenance contracts will be negotiated with LAN equipment suppliers.
SKA South Africa has identified the following ICT infrastructure team to support the LAN infrastructure upon full operation of the solution:
4 Cape Town based senior system administrators with one playing a 50% managerial
role and a 50% technical role;
2 Cape Town based junior support staff: one for desktop support and one for general
support
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A rota is envisaged, ensuring permanent presence of at least one of the senior
system administrators on site in the KAR. The junior support staff would move
between Cape Town, KAR and Rosebank as needed.
A stringent capacity building process is to take place during the Defects Notification period of
the LAN deployment contract. Part of this capacity building will be a Cisco certification on the installed equipment.
RFI Approach
Strict adherence to radio frequency interference avoidance requirements has been enforced
to ensure that RF emissions of the installed LAN equipment are kept to satisfactory levels. In
this regard the following key considerations apply for equipment in RFI sensitive areas (Losberg vicinity):
a. Location of equipment
i. All LAN units are located inside screened enclosures wherever possible;
ii. Where a screened enclosure is not readily available the LAN units are located as low down / close to ground as possible. In these instances an isolator
switch mechanism is provided to allow shutdown of LAN equipment;
iii. In other instances special screened cabinets may be considered necessary if RFI levels are beyond limits.
b. LAN Cabling
iv. LAN cabling outside screened enclosures is fibre and not copper wherever
possible. In instances where copper is required outside of screened
enclosures, CAT7 LAN cable with metal connectors is deployed as it offers favourable RFI shielding;
v. Ingress/egress to screened enclosures occurs via RFI ‘feed-through’ filters;
vi. All power cables as well as any copper cables will be run as close to ground
as possible (e.g. inside the trenches in the KAPB) or inside earthed metal
pipes or channelling;
vii. The standard NRS-083-3 is used as basis for installation design.
Before and during the construction phase a rigorous process is adopted to assess the RFI profile of equipment.
RAM (Reliability, Availability, Maintainability) Modelling
The RAM modelling undertaken for MeerKAT indicated an allowance for failures on the overall KAR LAN as approximately 24 hours per annum. This translates to a required total network
availability of 99.73%. These guidelines were utilised in the RAM Modelling performed for the KAR LAN. RAM modelling must be executed for SKA1 as part of Stage 1 as defined in
Reference Document [RD 3] – INFRA SA Integrated Logistic Support (ILS) Proposal to define the SKA1 system requirements.
Interface Control Requirements
The interface requirements between the KAR LAN and key data consumers CAM (Control and Monitoring) and SPT (Science Processing Team) as well as other data consumers has been
defined for MeerKAT.
A similar agreement will be defined for the SKA1 elements such as MGR, CSP, SDP and the
like.
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Other data transfer requirements
Apart from the data flows described above the LAN is required to support the following data interactions:
Business data
Non-telescope CAM
Table 16: Business Network and Non-telescope CAM requirements
Business Data Non-telescope CAM
VoIP-based telephony between the various sites requiring guaranteed QoS
An example of non-telescope CAM data flow is the BMS (building management system), offering centralised control and monitoring of key systems such as power systems, lighting etc. from off-site. CCTV footage from key locations such as equipment containers is also a consumer of LAN bandwidth.
IP-based video conferencing between Rosebank/KAR/Cape Town also requiring guaranteed QoS
File sharing
Access to financial and Administrative systems e.g. online costing, HR, procurement etc.
Internet traffic
Telephony
A Voice-over-IP solution is currently in deployment phase on the KAR LAN. The PABX is to be
hosted at Cape Town and is to be accessible from all end-points on the KAR LAN at Klerefontein, Losberg, Carnarvon and Rosebank via media gateways featuring a distributed
architecture.
The PABX design makes provision for Local Survivable Processors (LSPs) which allow the remote sites’ PABXs to work independently to the mother PABX server in Cape Town in the
event of WAN outage. These LSPs are deployed at the three breakout points, namely Cape Town, Carnarvon and Rosebank as indicated in Figure X.
The PABX installation makes provision for a range of wired (CAT6/7) and wireless (DECT)
handsets.
Provision is made for a Telephone Management System (TMS) for billing and reporting
purposes.
Voicemail mailboxes are provided and can be used by designated users (main site or remote
locations).
Expansion of MeerKAT LAN to address SKA1 requirements
A budgetary provision has been made in Reference Document RD 1 – INFRA SA Cost
Breakdown Structure for the following perceived MeerKAT LAN expansion to SKA1.
Proposed SKA1 Container Shed as per Option 1 (SKA1 Baseline Design) described
in Section 6.5.3.
It is envisaged that the LAN will be extended to the proposed two large container-based rooms to be housed adjacent to the KAPB by way of the installation of network switches and
associated equipment in each room. These switches would be fibre-linked back to the LAN chassis switch in the KAPB. It is envisaged that this LAN connectivity will primarily facilitate
the following traffic:
BMS traffic – the LAN switch will interface with the proposed BMS switch in each
container;
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IP telephony;
And other traffic as identified.
Expansion of the IP telephony platform
It is envisaged that relatively minor expansions to the MeerKAT telephony platform may be
carried out by way of, for example, provision of additional handsets and associated port equipment.
General expansion of LAN capacity
Although the existing LAN design has adequate provision for future expansion in terms of fibre and copper port capacity, additional expansion may be identified in the future.
Technical Risks and Mitigation measures
Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register which
describes the technical risks and proposed mitigation measures for this sub-element.
Capital, Operational and Maintenance Costs
Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown
Structure which provides the capital, operational and maintenance costs for this sub-element.
6.7.2. COMMS.BMS – Upgrade to Building Management System
No requirements have been defined in the SKA1 Baseline Design, however it is envisaged
that the MeerKAT building management system will be expanded for SKA1.
The MeerKAT project consists of a Building management System (BMS), Schneider Citect,
which monitors the key performance factors of the infrastructure. The BMS has a control
room at the Klerefontein complex which are operated by facility management personnel. The BMS is an Ethernet based system where the BMS points of each building is connected to the
Intranet. This allows easy expansion with control and monitoring at any point on the Intranet.
The BMS typically monitors the following parameters:
Grid power supply;
Rotary UPS power;
Data centre cooling systems;
Electrical power quality;
Fire systems;
Access control;
Lights;
Water systems;
Emergency power supplies;
Antenna power distribution.
The BMS interfaces with the ILS (maintenance management system) and the telescope CAM. This is illustrated in the following diagram:
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MeerKAT
BMS
System
Electrical
Systems
HVAC
System
Fire
Alarms &
Suppresion
Access
Control
Water
Systems
Lights
Maintenance
Man System
Telescope
CAM
BMS
Operators
MeerKAT
LAN
RFI
Environment
BMS
Software
Programers
Figure 12: BMS interfaces with the ILS and the telescope CAM
The BMS will be expanded to cater for the new requirements by adding more monitoring points and linking them to the Intranet. The new monitoring points will mostly be located in
the extended processor rooms and will consist of:
Temperature
Humidity
Status of entrance doors
Access control
Fire detection
Gas fire extinguishing system
Electrical power quality meters
Cooling system parameters
The BMS displays and database will be upgraded to correctly reflect and record the
parameters of the new BMS points.
6.7.3. COMMS.RADIO – Upgrade to Emergency Communication Radio System
Purpose of the System
There is no mobile (cell) phone reception at the site and along the roads to the site. This is part of the overall RFI management policy as mobile phones operating at 900 / 1800 or 2100
MHz will interfere with the operation of the radio telescopes on site.
However as part of safe operations, maintenance and construction of the various radio telescopes and related infrastructure, a means of communications is required for:
Emergency communications on site and along the road for SKA-SA staff as well as
contractors;
Operations and Maintenance activities by SKA SA staff;
Construction activities by contractors;
Security by the security service provider.
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In order to provide a mobile and fixed solution, a 66-88MHz analogue radio system has been
deployed on the site. The system selection and geographical layout was done taking into account the requirement not to interfere with the radio telescopes including:
The frequency selection to be well outside the telescope measurement frequency
bands;
The power levels (to avoid out of band saturation);
The location of repeater stations.
For contractors, the handheld and mobile radios are issued on a temporary basis (a deposit is
charged) and at the end of the construction activity the radios are returned to SKA SA.
Description of Current Radio System:
The radio system consists of the following elements:
Handheld radio transceivers;
Vehicle mounted (mobile) transceivers;
Base station transceivers;
Repeater stations on high sites.
Image 21: A typical hand held radio transceiver
Image 22: A typical mobile radio transceiver
Image 23 shows a typical base station transceiver at a security office (The transceiver is the
same as mobile transceiver):
Image 23: Radio Base Station at security office
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Image 24 shows the repeater antennas located on the SENTECH mast at the Wildeperdeberg
high site (about 100km from the core site):
Image 24: Radio Repeater antennas at the SENTECH High Site (100km from core site)
Description of the current radio system network
The SKA SA mobile radio network operates on 4 frequency pairs, plus 2 simplex frequencies,
and 6 CTCSS frequencies:
Table 17: Frequency allocations of the current radio system
Channel Location User Description Tx Freq (MHz) Rx Freq (MHz)
1 Wildeperdeberg SKA SA 70.3000 75.5000
2 Wildeperdeberg SKA Contractors 70.3625 75.5625
3 Meys Dam SKA SA 75.6375 70.4375
4 Meys Dam SKA Contractors 76.0000 70.8000
5 Simplex Chan SKA SA 72.7000 72.7000
6 Simplex Chan SKA Contractors 72.7125 72.7125
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Figure 13 provides an overview of the radio network links between the base stations and the
repeater stations:
Figure 13: Radio network showing links between Base Stations and Repeater stations
Additional requirements for SKA1
For SKA1, the intention is to re-use the current radio system with the following additions:
Re-issue the handheld and mobile radios to contractors;
Possible allocation of additional channels (additional frequency tone panels);
Depending on the coverage at the spiral positions, some additional repeater stations
might be required. This will be confirmed during Stage 1.
Wildeperdeberg
Repeater
MeysDam
Repeater
Losberg Office
Klerefontein
Security
Klerefontein
Site Manager
Klerefontein
Support Base
Losberg
Security
SKA Emergency Radio Network Rev 1
70.4375 75,6375
TX RXEMCOM 8155
75.5000 70.3000
72.7000 72.7000
CH1&4
8&1032
5&7
72.7125 72.7125
70.8000 76.00009&1175.5625 70.3625
75.6375 70.437576.0000 70.8000
TX RXEMCOM TB7100
CH
9&115&7
Repeater
75.5000 70.300075.5625 70.3625
TX RXEMCOM TB7100
Link to Wildeperdeberg
CH
8&101&4
70.3000 75.500070.3625 75.5625
TX RXEMCOM T800
Repeater
CH
8&101&4
70.4375 75.6375
TX RXEMCOM 8155
75.5000 70.3000
72.7000 72.7000072.7125 72.7125
70.8000 76.000075.5625 70.3625
CH1&4
8&1032
5&7
9&11
70.4375 75.6375
TX RXEMCOM 8115 Mobile
75.5000 70.3000
72.7000 72.7000072.7125 72.7125
70.8000 76.000075.5625 70.3625
CH1&4
8&1032
5&7
9&11
MeysDam
Border
Security
70.4375 75.6375
TX RXEMCOM 8115 Mobile
75.5000 70.3000
72.7000 72.7000072.7125 72.7125
70.8000 76.000075.5625 70.3625
CH1&4
8&1032
5&7
9&11
Losberg
Border
Security
70.4375 75.6375
TX RXEMCOM 8155
75.5000 70.3000
72.7000 72.7000072.7125 72.7125
70.8000 76.000075.5625 70.3625
CH1&4
8&1032
5&7
9&11
70.4375 75.6375
TX RXEMCOM TM8255
75.5000 70.3000
72.7000 72.7000072.7125 72.7125
70.8000 76.000075.5625 70.3625
CH1&4
8&1032
5&7
9&11
70.4375 75.6375
TX RXEMCOM 8155
75.5000 70.3000
72.7000 72.7000072.7125 72.7125
70.8000 76.000075.5625 70.3625
CH1&4
8&1032
5&7
9&11
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Technical Risks and Mitigation measures
Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register which describes the technical risks and proposed mitigation measures for this sub-element.
Capital, Operational and Maintenance Costs
Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown Structure which provides the capital, operational and maintenance costs for this sub-element.
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6.8. SKA.TEL.INFRA-SA.VEH – VEHICLES
The SKAO has established a CONOPS Working Group to define the Concept of Operations for
SKA1. Further work is required in Stage 1 on the Concept of Operations and the Logistic Support Analysis must be undertaken as defined in Reference Document [RD 3] – INFRA SA
Integrated Logistic Support (ILS) Proposal to define what the logistic support, resource, spares and stores requirements are for SKA1 which will impact on what vehicles are required
during the construction and operation of SKA1. At this stage, estimates have been made by
the INFRA SA Consortium for costing purposes only.
6.8.1. VEH.BAK – Additional Bakkies
SKA SA currently has 11 bakkies (utility vehicles) which are used on site. An additional 4 bakkies will be procured for MeerKAT.
It is envisaged that an additional 7 bakkies will be required on site for SKA1.
6.8.2. VEH.TRANS – Additional People Transporters
Contractors will make provision for transporting construction crews to the site.
The SKA SA currently has 2 people transporters which transport SKA SA support staff to site. An additional 2 people transporter will be procured during for MeerKAT.
It is envisaged that another 2 people transporters will be required for SKA1.
6.8.3. VEH.MAIN – Maintenance Vehicles
The following maintenance equipment has and will be procured for MeerKAT:
1 Mobile Crane (existing);
1 Cherry Picker (existing);
1 Water Tanker Truck (existing);
1 Grader (existing);
1 Tele-backhoe Loader (existing);
4 Trailers (RFI trailer; RFI trailer; Diesel trailer) (existing);
1 Roller (to be procured);
1 Tipper (to be procured);
2 Skyjacks (to be procured);
4 Trailers (to be procured).
It is envisaged that the following additional maintenance vehicles will be required for SKA1:
4 Skyjacks;
6 Trailers.
Technical Risks and Mitigation measures
Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register which
describes the technical risks and proposed mitigation measures for this sub-element.
Capital, Operational and Maintenance Costs
Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown
Structure which provides the capital, operational and maintenance costs for this sub-element.
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6.9. SKA.TEL.INFRA-SA.SEC – Site Security
6.9.1. SEC.SITE – Security
Background
Security of the facilities, equipment, staff, contractors and neighbouring farmers in the Karoo
is of primary importance to the project.
SKA SA has procured security services for the protection of the SKA Observatory facilities, which includes the pre-cursor facilities, site and staff via an open tender process. It is a
requirement that the security service provider be registered with the Private Security Industry Regulatory Authority (PSIRA) of South Africa.
Security Requirements
SKA Site and Site Complex Security Requirements
Figure 14 shows the Karoo Astronomy Reserve facilities.
The SKA Site makes provision for SKA1 and the SKA2 core site(s), the KAT-7 telescope, the MeerKAT telescope and the PAPER radio telescope. Security services are required to monitor
and control access all the facilities on site and at Klerefontein.
Figure 14: Locality map of the SKA Observatory
Current Security Services
Security at the Klerefontein Support Base
One security guard is stationed at the guardhouse at the Klerefontein Support Base. Security
is provided 24 hours a day for seven days a week; therefore two shifts of 12 hours each per day for seven days a week (including public holidays). The guardhouse is fully equipped with
electricity, ablutions and SKA SA’s emergency communication radios. The security guard
controls access to the Klerefontein SKA SA offices and workshops.
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Security at the SKA Site and Site Complex
Figure 15 shows the security detail at the SKA Site and Site Complex on the farms Losberg and Meys Dam. The turn-off from the provincial road to the SKA Site has been closed off and
access is controlled via security booms. Two guards (one stationed at the northern boom
near the Meys Dam farm, and one stationed at the southern boom near the Losberg farm) control access to the site on a 24 hour basis; therefore two shifts of 12 hours each per day
for seven days a week (including public holidays). Mobile guard huts have been erected at these booms and are equipped with electricity, ablutions and SKA SA’s emergency
communication radios.
The entrance to the Site Complex is also controlled via the guardhouse sited at the Site Complex. The Site Complex entrance grants visitors access to the KAT-7, MeerKAT, PAPER,
SKA1 and SKA2 sites (as well as all the facilities listed in Section 6.5.2), hence it is necessary to strictly monitor and control access. A single security guard is stationed at the guardhouse
on a 24 hour basis (two shifts of 12 hours each per day for seven days a week). The guardhouse is equipped with electricity, ablutions and SKA SA’s emergency communication
radios.
Figure 15: Security details required at the Site Complex, Meys Dam and Losberg
Reports and Reporting Structure
All incidents are reported to the SKA SA Karoo Site Manager and recorded in an Incident Reporting Book. Depending on the nature of the incident, a separate report may be lodged
with the South African Police Service offices based in Carnarvon. On a monthly basis a report consolidating and describing all the incidents is issued to SKA SA and the security service
provider’s head office. The status of the incidents is also discussed and recorded (for
example, the status of prosecuting trespassers).
Relationship with the South African Police
The South African Police Service (SAPS) has offices based in Carnarvon. Due to the strategic importance of the SKA SA facilities, the Carnarvon SAPS conducts regular visits to the site
and facilities to confirm that no incidents have occurred and / or to assist with any security-
related matters. SKA SA and the SAPS have a good working relationship and consequently any security-related matters that necessitate support from SAPS is addressed speedily and
efficiently.
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Security Services for SKA1
The security for SKA1 will remain the same as that which is currently available in the Karoo Astronomy Reserve. The only change will be the addition of two more guards to control
access to the proposed deproclaimed road, as discussed below.
Deproclamation of a Section of the Provincial Road
In 2011, SKA SA applied for a section of the Provincial Road (road P02996) between
Carnarvon and Brandvlei to be deproclaimed from a Provincial Road to a Private Access Road (see Figure 16:). The section that will be deproclaimed will run from the intersection of the
P02996 with the R357 to the T-junction with the road from Van Wyksvlei with the P02996
(see Figure 16) this is the same location where the Astronomy Complex as part of SKA2 will be sited). The closure of this road will limit traffic (which, in turn, will limit Radio Frequency
Interference caused by passing vehicles) and will also increase security. At the time of writing, the approval of this request by the Northern Cape Department of Roads was
imminent.
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Figure 16: Details of Deproclamation of Provincial Road
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Once the road has been deproclaimed, boomed-off access control points will be positioned at both ends of the deproclaimed road. The access control points will be similar to the access control points
at Meys Dam and Losberg (see Figure 15). One guard will be stationed in a mobile guard hut at the northern point (the intersection with the R357) on a 24 hour basis (therefore, two shifts of 12 hours
each per day for seven days a week, including public holidays), and one guard will be stationed in a
mobile guard hut at the southern point (the intersection with the Van Wyksvlei road) on a 24 hour basis (i.e. two shifts of 12 hours each per day for seven days a week, including public holidays).
Mobile guard huts at these booms will be equipped with electricity, ablutions, and SKA SA’s emergency communication radios.
Technical Risks and Mitigation measures
Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register which describes the technical risks and proposed mitigation measures for this sub-element.
Capital, Operational and Maintenance Costs
Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown Structure which
provides the capital, operational and maintenance costs for this sub-element.
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Annexure A
107102-SSG-ELEC-0010 Transmission Network Diagram
POWER.RETC-EP-0103 Proposed New SKA Phase 1 Dish Positions Sheet 1 of 2
POWER.RETC-EP-0104 Proposed New SKA Phase 1 Dish Positions Sheet 2 of 2
POWER.RETC-EP-0108 Proposed New SKA Phase 1 Dish Positions Sheet 1 of 2Electrical
Reticulation Random Layout
ACC.AP-CP-0001 Typical Teardrop Shape Platform
ACC.AP-CP-0002 Farm Road Locality Plan
ACC.AP-CP-0003 Farm Road Sheet 1of 4
ACC.AP-CP-0004 Farm Road Sheet 2 of 4
FOUND.MID-SS-0001 Proposed Antenna Foundation
The Losberg Site Complex Layout
Dish Assembly Shed Plan
Pedestal Integration Building Plan
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Annexure B
Foundation Loads
As the Foundation Load study developed, it became clear that the Precision Operations load case
above, with the very stringent rotational limit of 3 arc-seconds of rotation under the operational
condition, was the critical load case which ultimately defined the foundation size parameters. Furthermore, pad footings were discarded as they could not be made to work economically for this
load case. Instead, optimisation of pile lengths provided the distinction between perceived ‘pad foundation’ and ‘piled foundation’ solutions for individual antenna positions.
Table 3 provides a summary of the foundation requirements for all the load case considered.
Table 18: Antenna foundation solutions
Depth of competent material Pile Cap Pile Details Pile Length
Depth of competent material >3m 4200x4200 x 1200 4 x 750 Dia 10m
Depth of competent material < 3m 4200x4200 x 1200 4 X 750 Dia 5m
Foundation Geotechnical
Ground investigation information available to date
The culmination of information for the SKA1 project is represented in the geotechnical report for the
Phase 2 geotechnical investigation conducted by Aurecon between October and December 2010
(report 106477-G1-00). The geotechnical investigation was conducted for the MeerKAT Layout including 64 antennas and an additional 7 positions at the then identified ‘SKA Core Site’ (3 core site
bid configuration) and entailed the following:
Instrumented (Jean Lutz) Rotary percussion drilling (44 No. positions) to be able to define
the ground profile (soil and rock) at individual antenna positions;
Continuous surface wave (CSW) testing (44 No. positions) to define small strain stiffness
characteristics of the ground profile at individual antenna positions;
Plate load testing (5 No positions, 10 tests) to investigate the larger strain stiffness
characteristics of materials at expected founding level;
Test pitting (5 No positions, at plate load test positions) to define the upper ground profile
through visual inspection.
Simplified ground profile
The following distinctive soil or rock layers were identified from the site investigations done to date:
An upper, sandy horizon, either aeolian, hillwash or alluvial in origin;
A gravelly, poorly consolidated and un-cemented or poorly cemented horizon, of alluvial
origin;
Similar to that above, a gravelly horizon, generally dense but with layers of loose material;
A well cemented, gravel horizon which is thick and competent, and;
The basal horizon of mudstone.
The above horizons have all been tested during the 2011 geotechnical investigations
(reported in Aurecon report 106477-G1-00). A summary of applicable testing and general
comment on competency from a founding perspective are given below.
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Table 19: Relevant layers and their geotechnical parameters
Layer description Relevant profiles and tests Comment
Low strength gravel /
calcrete horizon.
M025 @ 1.3 m - CSW and plate load.
M039 @ 2.0 m - CSW and plate load.
M061 @ 1.5 m - CSW and plate load.
Significant reduction in strength when
saturated. Not considered a good
founding horizon for this reason.
Gravel and calcrete with
interlayered sand. M052 @1.5 m - CSW and plate load.
Some reduction in strength with
saturation. Concern that sand horizons
could have a dramatic effect if
saturated.
Thick, high strength, solid
calcrete.
M025 @ 3.5 m - CSW and plate load.
M061 @ 2.5 m - CSW and plate load. Competent layer.
Mudstone. M045 @ 2.5 m - CSW and plate load. CSW testing in all cases indicates good
strength material.
Note: M025 to M061 are borehole positions.
It is clear from all the testing that have been carried out that the sandy soils, whether alluvial, hillwash or aeolian in origin, which occur at the top of the profile are low density and highly
compressible in nature. Dramatic improvements occur in general at depths of between 2 and 3 m
below surface. While the addition of water to the upper sandy soils tends to result in a significant loss of stiffness, there is a markedly less dramatic response in the underlying calcareous or gravel
horizons.
Design strategy and assumptions
a. In an effort to come to appropriate founding solutions for individual antenna foundations and meet the very stringent rotational limit of 3 arc-seconds of rotation under the Precision
Operations condition, the following strategy was applied.
b. A likely conservative ground profile was defined. For this purpose conditions in borehole M048 (coinciding with antenna position M048) were considered representative of a
conservative ground profile. In summary, the ground profile is as follows:
i. 0 – 1.8 m: Loose to medium dense sand;
ii. 1.8 – 2.1 m: Dense gravel;
iii. 2.1 – 2.5 m: Medium dense sand;
iv. 2.5 – 2.8 m: Dense gravel;
v. 2.8 m – 2.9 m: Medium dense sand;
vi. 2.9 – 3.3 m: Dense gravel;
vii. 3.3 – 3.5 m: Medium dense sand;
viii. 3.5 – 3.8 m: Dense gravel;
ix. 3.8 – 4.1 m: Medium dense sand;
x. 4.1 – 5.0 m: Dense gravel;
xi. 5.0 – 5.3 m: Medium dense sand;
xii. 5.3 - 5.8 m: Dense gravel;
xiii. 5.8 – 6.3 m: Medium dense sand;
xiv. 6.3 – 6.9 m: Dense gravel;
xv. 6.9 – 7.3 m: Medium dense sand;
xvi. 7.3 – 8.0 m: Dense gravel;
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xvii. 8.0 – 9.0 m: Medium dense sand;
xviii. >9.0 m: Mudstone (the mudstone occurs from 5m, depending on the position).
c. Since the bulk behaviour of the subsoil system is what would drive foundation behaviour, this profile mostly provides information toward the variability of the profile and the depth to
bedrock. In relation to compressibility for design, the CSW testing was weighted significantly
more in relation to estimating likely founding conditions.
d. Two possible founding solutions were anticipated, namely shallow pad foundations onto
bedrock or competent calcrete, or piled foundations. As the study developed pad footings were discarded as they could not be made to work for the load conditions provided. Instead
optimisation of pile lengths provided the distinction between perceived ‘pad foundation’ and
‘piled foundation’ solutions for individual antenna positions.
e. Since the required movements for the operational cases are quite small, the strategy was to
conduct an iterative process by which a small strain stiffness ground profile was assumed. The likely maximum pile force for a specific piled foundation option was estimated and a
single pile finite element analysis was performed using Plaxis 2D (version 2010) to estimate the corresponding ground strain values. By assuming a relationship describing the
degradation of stiffness with depth, the iteration process then converged on a likely degraded
stiffness profile associated with the pile and load assumed. It was assumed that the relationship of stiffness degradation would be as described by Rollins et al. (1998) and is as
follows:
20max 102.1161
1
G
G
, where
G = Shear stiffness
Gmax = Small strain shear stiffness
= Shear strain
This process enabled identifying the likely pile cap size, pile configuration, pile sizes and lengths to be
estimated that would enable the design to meet the movement requirements. This was done through
pile group analyses conducted using the Repute 1.5 pile group analysis software.
The small strain ground profile is the basis of the iteration process. In report 106477-G1-00
`preliminary positions for ‘piled’ and ‘pad’ foundations were identified based on judgement of the compressibility of the ground profile (at the time not knowing the exact loading conditions to be
achieved). Based on this split, a minimum small strain stiffness profile was generated for each case
(piled foundation ground profile and pad foundation profile) by choosing the minimum small strain stiffness values measured during the CSW testing at positions anticipated to be either suitable for pile
or pad foundations. The combined stiffness profiles shown as young’s moduli (Emax), are as follows and are shown from foundation level (1.5 m from ground level) to what is perceived to be the
maximum penetration of the seismic waves into the ground in Figure 2.
When the analyses showed that the pad foundation solution was not viable (due to movements
exceeding the 3 arc-second rotational limitation) the ‘Pad Foundation Profile’ was used to estimate
the piled foundation solution for areas where pads were previously required.
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Figure 17: Small strain stiffness profiles used in the design
The final solution proposed, comprised piled solutions using 750 mm diameter piles installed to 10 m depth or 5 m depth (previous pad foundations) respectively.
Distribution of likely foundation applications
For costing purposes it is necessary to be able to estimate the likely distribution of antenna
foundation systems across the project. During the October 2010 to December 2010 ground
investigations, only the MeerKAT and SKA core site (as defined in the SKA SA Site Bid) was covered. This means that for the spiral arrays extending to a distance of roughly 100 km from the core site,
assumptions need to be made to extend the application of antenna foundation systems.
As part of the SKA SA Site Bid submission the antenna positions within a 180 km radius were
addressed in the report “Geological and Geotechnical desk study of the SKA remote telescopes
located within a 180 km radius from the centre of the array” dated 25 July 2011. Although this study spanned up to a radius of 180km, the findings can be used as an accurate reflection of the conditions
within a 100km radius, which covers the SKA1 area.
The process is described as follows:
Additional information sourced
Apart from report 106477-G1-00, the following information was scrutinised in a desk study:
a. Land type survey staff. 1972 – 2006. Land types of South Africa: Digital map. ARC-Institute
for soil, climate and water, Pretoria;
b. Google™ imagery of the site;
c. The published 1 : 250 000 scale geological series covering the SKA Site Bid Investigation Area;
i. 3022 Britstown;
ii. 3118 Calvinia;
iii. 3120 Williston;
iv. 3122 Victoria West.
0
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0 2000 4000 6000 8000 10000 12000
De
pth
be
low
Fo
un
din
g Le
vel [
m]
Small Strain Stiffness, Emax [MPa]
Piled Foundation profile(106477-G1-00)
Pad Foundation profile(106477-G1-00)
SKA.TEL.INFRA-SA.SE-SEMP-001
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Methodology used for assessing antenna foundations in a 180 km radius
The following methodology was used in 2011 to derive the most likely founding conditions to expect
at individual antenna foundation positions within the 180km radius of the core site. Geological maps were used to obtain the stratigraphic unit underlying each antenna position.
1:50 000 topographic maps and Google EarthTM imagery were used to identify the landform
on which each telescope would be located;
The pedalogical soil units as mapped by the ARC-Institute for Soil were identified for each
antenna position. It should be noted that pedalogical mapping only describes the soil profile
to a depth of slightly more than 1 m and as such was frequently not of much use unless
shallow rock was identified.
Using the above features and knowledge of the area, combined with the colour and pattern, or
texture of the satellite imagery, a probable soil profile was arrived at. This was constantly compared with existing information such as that obtained during the earlier field work or from knowledge of the
road cuttings, borrow areas for road construction, etc. Once the most likely soil profile had been
arrived at, the most likely foundation solution was derived for each antenna site.
Summary of antenna founding conditions
The antenna sites analysed in detail were restricted to roughly a 180 km radius from the approximate centre of the array.
The vast majority of the antennas are located near the centre of the array. These largely fall into the same main geotechnical unit encountered during the field investigation carried out in November 2011
and reported on in Report 106477-G1-00. This unit consists of Quaternary and Tertiary deposits of
alluvial or vlei sediments partially cemented with calcrete. The earlier work indicates that approximately 45% of the points falling within the Quaternary and Tertiary deposits would be
founded on pads and not piles. However, it is extremely difficult to identify which telescopes would fall into which category without actually doing field tests at each point. Assuming that the above
relationship holds true for the entire area underlain by Quaternary and Tertiary deposits, the
following numbers of piles and pads can be expected:
Table 20: Summary of piled and pad foundations
Total antennas piled according to desk study 2069 A
Total antennas on pads according to desk study See Note 234 B
Total sites (A+B) 2303
Piled on Tertiary or Quarternary 2032 C
Piled not Tertiary or Quarternary (A-C) 37 D
45% of piled will be pads on T or Q (0,45*C) 914 E
Therefore piles on T or Q are (C-E) 1118 F
Therefore estimated total piles will be (F+D) 1155 G
Total estimated pads will be (E+B) See Note 1148 H
Total sites (H+G) 2303
Note: Pad foundations were discarded as a solution. The significance of ‘pads’ relate to the use of
the stiffer ground profile where pad foundations were previously envisaged. This ground profile
resulted in the possibility to use fewer piles.
From the above, one can conclude that roughly 50% of the antennas within a 180km radius will
require a piled foundation solution and the remaining 50% a pad foundation solution for areas with significantly stiffer ground profile. As discussed earlier, it is safe to assume that the same conclusion
can be reached for antennas located within a 100km radius Note that pad foundations were
subsequently discarded as a solution and replaced with piled foundations with shallower piles.
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