ecp 11-0009 optical fibre splicing, testing and ......document number: ecp 11-0009 version: 2.0...

Document Number: ECP 11-0009

Version: 2.0

Date: 28/06/2018

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ENGINEERING COMMISSIONING PROCEDURE

ECP 11-0009

OPTICAL FIBRE SPLICING, TESTING AND COMMISSIONING REQUIREMENTS

Network(s): EPN, LPN, SPN

Summary: This standard details the requirements for the splicing, testing and commissioning of site-to-site optical fibre links.

Author: David Jeyakumar Date: 28/06/2018

Approver: Paul Williams Date: 06/08/2018

This document forms part of the Company's Integrated Business System and its requirements are mandatory throughout UK Power Networks. Departure from these requirements may only be taken with the written approval of the Director of Asset Management. If you have any queries about this document please contact the author or owner of the current version.

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Optical Fibre Splicing, Testing and Commissioning Requirements


Version: 2.0

Date: 28/06/2018

© UK Power Networks 2018 All rights reserved 2 of 17

Revision Record

Version 2.0 Review Date 06/08/2023

Date 28/06/2018 Author David Jeyakumar

Reason for update: Periodic review

What has changed: No content changes

Version 1.0 Review Date 31/03/2018

Date 13/12/2016 Author David Jeyakumar

New document to cover optical fibre splicing and testing



Version: 2.0

Date: 28/06/2018


Contents

1 Introduction ............................................................................................................. 4

2 Scope ....................................................................................................................... 4

3 Glossary and Abbreviations ................................................................................... 4

4 Testing Requirements ............................................................................................. 5

4.1 Fibre Testing ............................................................................................................. 5

4.2 Fibre Identification ..................................................................................................... 5

4.3 Testing Prior to Installation ........................................................................................ 6

4.4 Testing After Cabling ................................................................................................. 6

4.5 Testing Following Completion of External Splicing .................................................... 6

4.6 End-to-end Testing Following Completion of Terminations ........................................ 6

5 Splicing in External Joints, BFPs and CTPs .......................................................... 7

6 As-Built Records ..................................................................................................... 7

7 Commissioning Direct Fibre Links between Hardware Interfaces ....................... 8

8 References ............................................................................................................. 10

8.1 National and International Standards ....................................................................... 10

Appendix A – Workmanship Example ............................................................................. 11

Figures

Figure 7-1 – Example Optical Link Budget from ILM, Transmit and Receive Levels, and Receive Sensitivity ............................................................................................... 9

Figure 8-1 – Splice Tray ...................................................................................................... 11

Figure 8-2 – Splice Tray in a CTP-type ODF ....................................................................... 12

Figure 8-3 – OPGW-UG Terminal Tower Splice Tray ......................................................... 13

Figure 8-4 – Underground Straight 24-fibre Joint Splice Tray .............................................. 14

Figure 8-5 – Patching Side of ODF-type Wall Box ............................................................... 15

Figure 8-6 – Termination side of ODF-type Wall Box .......................................................... 16

Figure 8-7 – Wall Box with Protective Cassette Covers ....................................................... 17



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1 Introduction

This document details the splicing, testing, commissioning and recording requirements for site-to-site optical fibre links.

Along with copper cables and wireless communication solutions, optical fibre links are part of the communications system operated by UK Power Networks for control, monitoring, and protection of the electrical network. Splicing, testing, commissioning, and provision of records, are all important activities in the delivery and hand-over of optical fibre links prior to use for the above critical functions.

2 Scope

This document applies wherever splicing, or testing, or commissioning is carried out by a UK Power Networks supplier or contractor as part of the delivery of optical fibre installations.

3 Glossary and Abbreviations

Term Definition

BFP Building Flexibility Point

CTP Customer Terminal Panel

ILM Insertion Loss Measurement

Microbend An imperfection in the optical fibre, created during manufacture, which is not visible to the naked eye, and which can cause reduction of transmitted optical power.

Macrobend A large visible bend in the optical fibre which is caused by poor handling or installation, and which can cause reduction of transmitted optical power.

ODF Optical Distribution Frame

OTDR Optical Time-Domain Reflectometer

SOR An electronic file extension for OTDR trace files traces

TIA Telecommunications Industry Association, a body that develops voluntary, consensus-based industry standards for a wide variety of Information and Communication Technologies (ICT) products.

TRC An electronic file extension for OTDR trace files traces



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4 Testing Requirements

4.1 Fibre Testing

The fibre installation process involves several tests. These are summarised in Table 4-1 below, and their application at the various stages of delivery are given in Sections 4.3 to 4.6.

Table 4-1 – Optical Fibre Tests

Test Type Results Format

Drum Test OTDR at 1550nm

All Fibres

SOR or TRC files plus pdf copies showing both distance and attenuation axes zoomed-in to a well-defined scale

End to End OTDR Test

OTDR test at 1310nm and 1550nm

All fibres

SOR or TRC files plus pdf copies showing both distance and attenuation axes zoomed-in to a well-defined scale

End to End ILM Test

ILM at 1310nm and 1550nm

All Fibres

Spreadsheet identifying location, cable and fibre number (if the supplier is not required to terminate the fibres within substations, then recording of loss measurements is not required, however a continuity test shall still be performed in order to prove that fibres are correctly spliced, i.e. there are no crosses)

Splice exception sheet

OTDR results for each location with bidirectional average losses above 0.05dB

Spreadsheet identifying location, cable and fibre number of the exceptional events. These are splice events that are discussed under section 4.5 (i.e. after three splicing attempts)

4.2 Fibre Identification

Optical fibre cables typically consist of elements stranded around a central strength member. Some of the elements are tubes which contain the fibre optic cores. A single tube shall not contain more than 12 fibres.

Document TIA-598-D defines a colour code for the cores in each tube, and this is set out in Table 4-2.

Table 4-2 – Optical Fibre Identification

Fibre Colour Fibre Colour

1 Blue 7 Red

2 Orange 8 Black

3 Green 9 Yellow

4 Brown 10 Violet

5 Slate 11 Rose

6 White 12 Aqua



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4.3 Testing Prior to Installation

Once the cable drum has been delivered, Drum Tests at 1550nm on each fibre from the cable end on the outside of the drum shall be taken to ensure that there is no damage prior to installation (see Table 4-1 for test details). Testing at the 1550nm wavelength will show up any microbends from the manufacturing process. UK Power Networks reserve the right to witness these tests. The testing party shall inform UK Power Networks of any cable damage identified.

4.4 Testing After Cabling

After the cable is installed but before any route splicing occurs, OTDR tests shall be carried out on each fibre length in one direction to ensure that there is no damage during installation. These tests shall be carried out at 1550nm to check for macrobends or breaks caused by cabling damage and the results shall be presented to UK Power Networks. These tests are identical to the Drum Tests (see Table 4-1 for test details).

4.5 Testing Following Completion of External Splicing

After the route splicing is complete and cable ends have been pulled into UK Power Networks buildings, the contractor shall record bidirectional End to End OTDR test readings from bare fibre ends for each fibre at both 1310nm and 1550nm (see Table 4-1 for test details). Any splices exceeding the average bidirectional maximum limit shall be re-spliced. If the maximum limit cannot be achieved, then the lowest possible attenuation level shall be accepted with evidence of three re-splicing attempts (at the discretion of the UK Power Networks Operational Telecoms representative) as long as the overall (end to end) loss is within the specification for that fibre.

The contractor shall also use optical loss sets (light source and power meter) to identify each fibre from bare-end to bare-end to ensure that there are no crossed fibres or tubes. ILMs are not required to be recorded at this stage because the fibres are not terminated.

If accessing any splice enclosures in the future is likely to be difficult, (i.e. for remedial splicing work) then the contractor shall provide a testing engineer at one of the cable end locations, to OTDR test through all fibres ‘real time’ as the splicing is carried out.

Table 4-3 - Acceptable Splice and Connector Losses

Parameter Max Value Limitations

Bidirectional Splice Loss

0.05dB Where not possible, i.e. due to fibre manufacture anomalies, three attempts shall be made to meet this criteria and evidence of these attempts shall be recorded as OTDR traces and presented to UK Power Networks with the final test results As-Built pack.

Connector Loss 0.5dB Per connector

4.6 End-to-end Testing Following Completion of Terminations

UK Power Networks Operational Telecoms representatives or their approved contractors shall carry out termination works of all fibre cables within UK Power Networks buildings. This shall include the internal cabling, mounting of fibre wall boxes, installation of cabinet and ODFs etc. On completion of all satisfactory splicing and testing; End to End OTDR and End to End ILMs shall be carried out at both 1310nm and1550nm from the ODF panels (see Table 4-1 for test details). The results shall be recorded and presented to UK Power Networks Operational Telecoms for evaluation and comparison with those provided by the installation Contractor.

For generation connections (e.g. photovoltaic farms and wind farms) where the same contractor is responsible for external splicing and internal terminations, the testing activities described in Section 4.5 may be carried out from the ODFs rather than bare-end fibres.



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5 Splicing in External Joints, BFPs and CTPs

All fibres shall be straight spliced in joints unless instructions from UK Power Networks state otherwise. Fibres shall be unravelled, cleaned and degreased using suitable spirit and talcum powder to ensure that individual fibres move freely within the splice tray, i.e. they do not stick together. This will ensure that spare fibres can be worked on in the future without causing bends to live fibres. Each tube shall be spliced in a separate tray.

Fibres shall be pre-measured in splice trays with sufficient length to ensure that they are stored neatly. Only re-spliced fibres (due to remedial work) should be shorter than the others, but loops of fibre should provide compensation for the reduced length. Note that cable tubes are brittle and susceptible to kinking, and shall therefore be stripped back to protrude no more than 40mm beyond the cable butt. Transport tubing shall then be used between the cable tube and splice tray, and dressed around the inside of the enclosure to allow a reasonable amount of fibre slack. The transport tubing shall be a secure and tight fit over the cable tubes and be suitably restrained at the splice tray with two cable ties. The cable ties shall be filed back to ensure that there are no sharp edges after removal of the excess. Refer to Appendix A for examples.

6 As-Built Records

In addition to the OTDR trace files and ILMs, the contractor shall provide photographs of each splice enclosure with close ups of the splice trays using a macro camera setting so that the quality of fibre preparation and splicing work is clearly visible. Further photographs of the splice enclosure fitted in a splice chamber, or on a tower (with the tower reference number) shall also be submitted to verify that the close up is of the correct enclosure.

The contractor shall also provide a spreadsheet showing the optical distance (from substation in both directions) to each splice location and its underground or overhead location, i.e. splice chamber grid reference and OHL tower number.

In summary, the following documentation shall be submitted to the UK Power Networks Operational Telecoms representative for acceptance and sign off before the contractor shall be paid. (Note that list is in order of importance).

1. Copies of the splicing and testing contractor’s qualifications and certificates.

2. Detailed close-up photographs of each splice tray, enclosure, wall box and ODF.

3. A full set of ILM results in a suitable spreadsheet for each fibre core.

4. OTDR traces in native format and pdf (using a suitably detailed scale).

5. A splice exception sheet.

6. Summary sheet showing splice location optical distances.



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7 Commissioning Direct Fibre Links between Hardware Interfaces

This section is a guide to connecting systems on to the fibre and ensuring that transceiver link budgets are appropriately considered alongside ILM results.

A link from site A to site B is presented on ODFs at each end and fibre patch cords are run to the hardware interfaces at each end.

1. At site A; inspect and clean the fibre patch cord; preferably with a ‘Cletop’ Cassette Cleaner or similar product. Also, clean the ODF and equipment fibre ports using a ‘one click’ type connector cleaner. Then connect the patch cord to the transmit port of the local device. Connect the other end of the same patch cord to an optical power meter, then measure and record the received level. Remove the connector from the optical power meter and connect it to the ODF on the assigned port.

2. At site B; inspect and clean the fibre patch cord (as previously described) and connect it to the ODF on the corresponding fibre port. Connect the other end to an optical power meter and measure and record the received level. This is the level that the local device at B will receive from the transmitter at site A. Then connect the patch cord to the receiver of the unit at site B.

3. Carry out the same procedure for the link transmitting from B to A.

Ensure that these measurements are compatible with the ILM readings (measured in dB) by subtracting the receive level from the transmit level (measured in dBm) in each case, including the additional connector losses. The ILM readings will include connector losses and different patch leads will vary this value by a generally insignificant extent, as long as the connectors are kept scrupulously clean.

An example is shown in Figure 7-1A transceiver transmit level of -6dBm over a fibre with an ILM reading of 5dB should give a receive reading of -11dBm at the receive end ODF. In this case, the manufacturer’s specified receive sensitivity for the equipment transceiver shall be at least 5dB lower than -11dBm. If this sensitivity is -16dBm, then the link is working with 5dB of spare optical budget when receiving a level of -11dBm.

This ‘spare’ 5dB will allow fluctuations in link budget caused by bending patch leads or fibres in cassette trays without failure of the system.



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Date: 28/06/2018


-6 dBm received

here

-11 dBm received

here

Receive sensitivity of transceiver is

-16dBm

Result: A spare optical budget of 5dB.

Transmit level of -6dBm (measured at ODF)

An ILM reading of 5dB from ODF to ODF

Figure 7-1 – Example Optical Link Budget from ILM, Transmit and Receive Levels, and Receive Sensitivity



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8 References

8.1 National and International Standards

TIA-598-D Optical Fiber Cable Color Coding



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Appendix A – Workmanship Example

The photos in this section show the expected quality of workmanship typically required by UK Power Networks. Photographs submitted with as-built records shall show a similarly detailed level of the subject matter.

Annotated close up of a splice tray showing fibre lengths accurately measured to avoid macrobends and untidy loops. Transport tubing is securely fixed as it enters the cassette.

Figure 8-1 – Splice Tray



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Close up of splice tray in a CTP-type ODF. Pigtail fibre lengths are accurately measured to avoid macrobends and untidy loops are securely stored in the cassette.

Figure 8-2 – Splice Tray in a CTP-type ODF



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Close up of splice tray in an overhead OPGW to underground fibre joint on a terminal tower. Fibre lengths are accurately measured to avoid macrobends and untidy loops. Due to the large cassette size, a greater length of slack can be stored to allow remedial splicing.

Figure 8-3 – OPGW-UG Terminal Tower Splice Tray



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Close up of splice tray in an underground straight 24 fibre joint. The cassette has an additional spooling area so that a greater length of slack can be stored to allow remedial splicing.

Figure 8-4 – Underground Straight 24-fibre Joint Splice Tray



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Close up of an ODF-type wall box, typically for use in a generation site. The box has two sections; this is the patching side.

Figure 8-5 – Patching Side of ODF-type Wall Box



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Close up of an ODF-type wall box, typically for use in a generation site. The box has two sections; this is the side used to terminate the external cable on to pigtails. Note that the cable strength member is terminated at the top to prevent the cable being accidentally pulled through the gland.

Figure 8-6 – Termination side of ODF-type Wall Box



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This is the same wall box shown in figure 5 but with the cassette covers fitted to protect the splices

Figure 8-7 – Wall Box with Protective Cassette Covers

ecp 11-0009 optical fibre splicing, testing and ......document number: ecp 11-0009 version: 2.0...

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