ls1 the upgrade of 600 a energy extraction systems

TE-MPE LS1 workshop – November 22-23, 2012 G.J. Coelingh TE-MPE-EE

LS1The upgrade of

600 AENERGY EXTRACTION SYSTEMS


600 A EE; what, where, how ? Reliability Hardware Failures to be cured Why upgrade? Failure causes Solutions LS1 actions Resources Planning Showstoppers Non LHC activities during LS1

Overview


Energy Extraction 600 A circuit


SnubberCapacitor

0.8 mF

Fuse32 A

SwitchA

SwitchB

SwitchZ

Equalizing Resistors

each

600 A Energy Extraction Facility

600 A warm cables 400mm2

600 A warm cables 400mm2


600A Energy Extraction Systems

202 systems installed in the LHC tunnel in corrector circuits with stored energy between 2.2 and 150 kJ

In 15 different locations; 8 x UA parallel service tunnel and 6 x RR and 1 x UJ tunnel

caverns

Systems developed in close collaboration between CERN and the Budker Institute of Nuclear Physics (BINP), Novosibirsk, Russia.


Reliability

Systems reliability from protection point of view:No opening failures during Fast Power Abort events or tests

(> 100.000 openings since 2005)

2 independent opening mechanisms/circuits per breaker; guaranteeing 6-fold redundancy

Calculated by Antonio Vergara in December 2003: System Failure probability in 20 years of operation < 0.01% (Preventive maintenance!!)


Reliability (2)

Systems reliability from hardware failure point of view: 6 hardware failures in 2010 1 hardware failure in 2011 3+1* hardware failures in 2012

For operation: 2 failures per year – not in shadow Mean Time To Recovery : 4 hours

(including preparation, access and travel) All failures were “fail-safe” for the s.c. circuits

reducing the availability of the system.

Changes with respect to 2010 operational year :

Preventive maintenance with help of automatic analysis and tracking software tool.


Hardware Failures treated during LS1

5-10/year - 95% of all failures: Breaker refuses to close Loosening of holding coil mechanism – LHC re-start delayed

1/year - Breaker is physically open but indicates “CLOSED”

micro-switch not actuated / main axle – LHC re-start delayed

1/year - Breaker main contact re-bounces on micro-switch main axle – LHC re-start delayed


Why do we upgrade? Correcting measures are relatively easy < 100 kCHF

This upgrade will improve the availability of 600 A EE systems for LHC operation by 4-8 hours per year….

Less preventive maintenance


Failure causes

1- Loosening of holding coil mechanism Weak design of U-shape

2- Micro-switch not actuated Tolerances in dimensions of housing

3- Main axle fixation Weakness during production – not an increasing

fault


1- Loosening of holding coil mechanism Weak design of U-shape and dimensional tolerances

Solutions

Needs to achieve Plate Glue Action in all 606 breakers

Open all breakers (anyway foreseen for regular maintenance)Plate gluing – Once open: 2-3 minutes per breaker


2- Micro-switch not actuated (temporarily) Tolerances in dimensions of housing

Already tracked by automatic analysis software toolLeading to an unscheduled but still preventive maintenance

intervention (in the shadow)

On-going but to be extended with advice in form of logbook entries (MPE-MS)

Solutions cntd.


3- Main axle fixation A loose main axle means no current in 2 oo 3 phases in

the CB leading (> 200A circuit current) to overheating of the 3rd phase.

Weakness during production – no increasing numbers Manufacturer has improved this process for new breakers For existing breakers no solution.. But..

We can track it because of known early symptoms

Solutions cntd.

Already tracked by the same automatic analysis software tool but with very few cycles left – we can measure the System Resistance!

Leading to an unscheduled corrective or preventive maintenance intervention


3- Main axle fixation tracking improvement - Measurement

Solutions cntd.

Needs to achieve Improvement of existing Voltage Measurement Channel

Replacement of Voltage Divider by low impedance divider and noise reduction components (270 pcs MPE-EM)

Replacement of Measurement Board by low noise separation amplifier (270 pcs: MPE-EM)

Replacement of DQAMS by 12 bit to 24 bit ADC (MPE-EP & EM: 220 pcs)

Voltage measurement taps to be improvedHi-level SW for on-line analysis (MPE-MS)


3- Main axle fixation (and loose bolts) Save the EE system

in case we don’t track (or too late) it with software tools Overcurrent in one or two phases of the breakers will lead to over-

temperature on the Equalizing Resistor and eventually destroy all breakers in one system

Installation of a Thermostat on each Equalizing Resistor will trip the system early before hardware damage is done

A spare internal interlock channel is available and wired up to the power board.

Solutions cntd.

Needs to achieve Installation of Thermostats

Reprogramming of Firmware in all 404 interface cards (MPE-EP)Allow trip on over temperature of Equalizing Resistor

»Profit to limit cycles of the breakers


LS1 Actions

Breakers - Regular maintenance and Consolidation

Equalizing Resistors – Installation/wiring of Thermostats

Voltage measurement-channel improvement

Visual inspection of main axles – Endoscope

IST SCT HWC


Resources

Maintenance IST Installation man-hours T/TE man-hours E/TE

per point per pointEven point - 2 UAs 100 30Odd point - 2 RRs 40 10P7 right 30 10P7 left 30 10UJ33 65 20

Total LHC approx. : 630 h 160 h

130 man-days6 man-months


Planning (not incl. SCT and HWC)

ANYTIME – “ANYWHERE” April 2013 – April 2014 – 6 man-months –

Team of 3 persons could come 2 x 1 month

Man-power Calculations based on one team of Specialists from BINP

Perfect preparation before start of activityOne Engineer or TE as team leader plus two TechniciansWorking in a “train”

Start – to – Finish one point, including IST

But ..


Planning SCT & HWC

SCT & HWC – 2014 SCT was presented as not needed for 600 A EE but …

latest tests show.. Yes, if we could we should 1 day per UA or RR – 2 TE or E

15 working-days - NO recourses allocated yet

HWC like SOF test PLI3.b1 – remotely from CCC – Automatic Analysis of PM

PNO.b1 – 1 day per UA or RR – 2 TE or E 15 working-days - NO recourses allocated yet


“Showstoppers” Preparation for LS1

Planning – Tests – Tooling – Purchasing (thermostat-study still to be finished)

A LONG WAY TO GO!!!

No reference contract with Russia If done by non-experts

More CERN staff needed for training, the actual job, follow up, debugging of collateral damage etc. Might delay re-start after LS1.

Spare Circuit Breakers: DZNVA – Visit in March 2012 - Manufacturer’s premises in very bad state and

only 20% occupied - might stop delivering (special) breakers Currently: 28 spares (13 operational – 15 to be qualified before TS4) Consumption average: 8-10 per year (including preventive changes)


Non LHC activities during LS1 Currently low in spare systems (<1%) and

spare breakers (3-4%) In order: 20 spare systems – ATA Autumn 2013 – to be

mounted and tested in ISR test building Urgent: to order 120-150 spare breakers in order to

exclude the regular need of Russian Specialists and cover mid-term needs.

Long term strategy for 600 A EE systems: Switch partially (UA areas) to solid state breakers

R&D necessary: 2012 development of Lab version (Bi-polar)2013/2014 development of prototype – 0.5 day/week2015 Market Survey/Tender

What about the study to prevent Quench-Back on RQTF/Dthe installation of lower dump resistances in 600A circuits


Thank you for your attention.. So far..!


Questions before continuing with Cable

Activities?


Planning activities GJC Preparation 600 A EE activities to start LS1:

70% Installation/Maintenance – 2013

Coordination – during the activity 50% IST – 2013

Coordination – during the activity 50% SCT – 2014

Coordination/installation/Analysis: 70% during activity HWC – 2014

PLI3.b1 – remotely from CCC – Automatic Analysis of PMActivities if automatic analysis fails

PNO.b1 – 1 day per UA or RR – 2 TE or ECoordination/installation/Analysis: 70% during activity


1- Loosening of holding coil mechanism Weak design of U-shape and dimensional tolerances

Vibrations causing the closing failures – if starting increasing with cycles To prevent vibrations the manufacturer proposed decreasing of gaps on the side of

the U-Shape by gluing small plates between the U-shape and the housing Several cycling tests have proven the efficiency of this method. Number of closing

failures reduces from typically 4% to less than 0.5 % during lifetime of breaker

Solutions

Needs to achieve Plate Glue Action in all 606 breakers

Open all breakers (anyway foreseen for regular maintenance) Plate gluing – Once open: 3-4 minutes per breaker Glue = Silicon paste (Dow Corning Mil. Standard) approved by breaker

manufacturer


Solutions


3- Main axle fixation tracking improvement Weakness during production

If this occurs there’s an increase from 0.5 mΩ to max 1.25 m Ω of system impedance due to decrease of contact pressure in the breaker.

By improving the existing voltage (drop) measurement, correlating it to the circuit current, can lead to an early warning, preventing the circuit to trip

An intervention can be planned in the shadow

Solutions cntd.

Needs to achieve Improvement of existing Voltage Measurement Channel

Replacement of Voltage Divider by low impedance divider and noise reduction components (MPE-EM)

Replacement of Measurement Board by low noise separation amplifier (MPE-EM)

Replacement of DQAMS by 12 bit to 24 bit ADC (MPE-EP & EM) Voltage measurement taps to be improved Hi-level SW for on-line analysis (MPE-MS)


3- Main axle fixation (and loose bolts) Overcurrent in one or two phases of the breakers will lead to over-

temperature on the Equalizing Resistor and destructing all 3 breakers in one system

Installation of a Thermostat on each Equalizing Resistor will trip the system early before hardware damage is done

A spare internal interlock channel is available and wired up to the power board.

Solutions cntd.

Needs to achieve Installation of Thermostats and Wiring up to the spare channel

Dismounting, drilling, threading of all 606 Equalizing Resistors Mounting of pre-cabled Thermostats and a connector PCB Wire installation from connector PCB to Burndy connector SK24 Reprogramming of Firmware in all 404 interface cards (MPE-EP)

ls1 the upgrade of 600 a energy extraction systems

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