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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Long Shutdown 1 Status Report Energy Extraction Systems On behalf of all EE teams involved

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Energy Extraction ; what, where & how? Split: 13 kA EE and 600 A EE LS1 actions and details Findings Status + open issues General lessons learnt Overview

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Energy Extraction principle

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Energy Extraction Systems 13 kA main circuits: 32 systems for Main Dipole RB and Main Quadrupoles RQF/RQD circuits. Stored energy between 22 and 1300 MJ 600 A corrector magnet circuits : 202 systems for circuits with stored energy between 2.2 and 150 kJ In 15 different locations; 8 x UA parallel service tunnel and 6 x RR/tunnel and 1 x UJ33/tunnel caverns

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE 13 kA main circuits Energy Extraction Systems

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Overview of the 13kA EE systems Interface electronics BCMs Extraction switches DQRQ R=7.7 or 6.6 mOhms

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE 13 kA EE LS1 goals / actions list 1. 1. Main quadrupole switches: Installation of new arc chambers with higher voltage rating (from 200 to 1050 VDC) and snubber capacitors for voltage transient and arc suppression during commutation 2. 2. Mechanical modifications of all extraction resistors in the main dipole circuit preventing damage and short-circuit in the case of double energy deposit 3. 3. Replacement of thermostats on the extraction resistors in the main dipole circuit by a different type with higher switching point (80 C).

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE 13 kA EE LS1 goals / actions list cntd 4. 4. Replacement of the power switching relays and circuit breakers in all 64 switch controller units (DJPC). New relay with different (hardened) contact surfaces 5. 5. Re-configuration of all extraction resistor values - back to the origin (2 x 70 m for dipole circuits and 7.7 m/6.6 m for quads) 6. 6. Relocation of EE components in LHC points 1 and 5 (both sides) 7. 7. General preventive maintenance program incl. verifications of all bolted contacts and of multi-pin connectors in all elements applied to all 32 switch facilities

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Energy Extraction ; what, where & how? LS1 actions and details Findings Status Lessons learnt Overview

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Findings upgrade / maintenance Switches: Broken or misaligned micro- switches/status indicators (8 cases) Switches: support - Broken insulators (4 cases) General: Burndy connector pins deformed or pushed inwards (> 60 cases) or wire insulation damage General: ODU connectors - broken or partially melted pin (2 cases) Electronics chassis: Power resistor insulation damaged (one case)

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Examples Untightened screws in electronic cabinets and racks Broken or badly fixed pins in connector or socket

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Broken cable insulation 2250 cables / 51000 pins checked: 67 cables/socket/pins with problems were found

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Findings Individual System Tests Insulation Tests Several problems reported with high leakage currents. Causes: - Dust mixed with metallic particles (due to grinding close to the Resistor body) leading to breakdown voltages on RQD resistor -Flexible water connections Functional Tests Breaker Control Module with problems on PCB called On-Off control card Collateral damage due to maintenance interventions. broken connectors/pins and cables/ wires not well connected (again???) Cold welds UA67 Equipment suffered from mains voltage oo spec.

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Findings Short Circuit Tests Heat run or thermal evaluations included Interconnections water cooled cables Rcc < 0.6 So called conical connections show resistances higher than specified. In some points > 30% of all connections show high resistance even if cables/connections were not touched during LS1 Will lead to thermal runaway at currents above 7 kA Permanent measurement systems will be developed and installed! (2015/2016)By who?

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Findings Short Circuit Tests ctnd. Heat run and / or thermal evaluations included During heat-run RQF.A78: Switch Open Failure Most likely EMI related. Double signal reaction 1- Fire all heaters: was already decommissioned in 2008 2- Fast Power Abort leading to opening of the breakers. Now also interrupted. High contact resistances on breaker contacts Rbc < 20

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Energy Extraction ; what, where & how? LS1 actions and details Findings Status Lessons learnt Overview

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE STATUS 13 kA EE All findings corrected / repaired : EE Maintenance and Upgrade: 100% completed IST/SCT: 100% completed

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE STATUS 13 kA EE Open issues: 1 Non-opening of switches on FPA request After installation of earth-fault detection cards. Workaround: installing 100 parallel resistor on opto coupler Completed except RR57 (no access) 2 Former polarity check of CB holding coil and pulse coil not fail safe. New test equipment and procedure established. (on-going, 50% completed) 3 Final check before handover of systems to HWC List established, treated like consignation yellow-paper

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE 600A corrector circuits Energy Extraction Systems

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE 600A Energy Extraction Systems

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE LS1 Upgrade - main goals 600 A EE Improve circuit-breakers availability/reliability (reduce nr. of closing failures) Decrease nr. of interventions for corrective and preventive maintenance Improve voltage measurement system (main axle) From V to mV level =>Early warning on increasing system resistance With additional interlock on over-temperature Prevent > 90 % of all problems of period pre-LS1

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE 600 A EE LS1 actions LIST 1New Voltage divider board 2New voltage measurement wires + Vtap 3Thermostats on equalizing Resistors 4New Thermostat connection PCB 5Wiring Thermostat PCB to connector SK24 6Replacement of A and Z imbus to hexag. screws 7Screwed connections "torque" check 8Breaker maintenance general and Holding coil fixation 9Visual inspection main axle (new) 10Interlock PCB resistor change 11Interface card firmware upgrade 12Acquisition and Monitoring board upgrade 13New measurement PCB 14Replacement of transformer (- overheated zener) 15Dump Resistor modification RQTL9 systems in P3 and P7

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Energy Extraction ; what, where & how? LS1 actions and details Findings Status Lessons learnt Overview

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Findings during maintenance Zener diode overheated patch from 2008 to lower DC voltage on CB holding coil Decided to remove zener and change the transformer Several loosened screws (>20) were reported randomly located (> 27000 checked) Visual inspection show one suspect breaker with possible weak main axle fixation UA27 - RSF1.A23B1 - B Breaker (decided to keep under observation)

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Findings Individual System Tests + Closing failures reduced by 90% - Collateral damage due to maintenance interventions Mainly connector pins and wires but also water-damageUA67

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Findings Short Circuit Tests During SCT many breakers (50 oo 606) found with high contact resistance despite cleaning of contacts during maintenance period in 2013 Increasing number of breakers towards the end of SCT period: P6, P7, P1, P2: < 5%. short time between maintenance and SCT P8 & P3: 30%. Reasons: One year after cleaning, high humidity (or water on the floor during long time) systems unpowered and breakers opened P4 and P5: 10 % of breakers. Reason: almost one year after cleaning systems unpowered and breakers open).

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Findings Short Circuit Tests ctnd Breaker A : ROD.A45B2 - Uph_r: 79 mV @ 600A Breaker B : ROF.A45B1 - Uph_t: 82 mV @ 600A Limit: 70 mV normally 50-65 mV Contacts are clean and current sharing is excellent. First time happening. Two breakers to be monitored closely during HWC In case of further degradation breakers will be changed.

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Energy Extraction ; what, where & how? LS1 actions and details Findings Status Lessons learnt Overview

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE STATUS 600A EE All findings corrected / repaired / monitored : 100% completed 600 A EE Upgrade: 100% completed IST: 100 % completed SCT: 100 % completed..

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE STATUS 600A EE Open issues: 1 - All AMS cards to be reprogrammed (Sector 67 done) init. not foreseen by 600 A EE team now it is (AS+MB) 2 PLI3.b1 and PNO.b1 automatic measurement system Was developed to register (without tunnel team presence) of each system: Opening time + Voltage drop (two measurement wires and two trigger wires per system) After conclusions of SCT: Now also current sharing (4 wires per system)(still not enough to qualify system)

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Energy Extraction ; what, where & how? LS1 actions and details Findings Status Lessons learnt Overview

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Lessons learnt Problems reconnecting cables to current leads after SCT (Alignment). Flexibles needed instead of copper blocks In future LS: Before any action: Nominal infrastructural conditions: - Cooling and ventilation - Mains power preferably on UPS Meaning starting late(r) But also: - WorldFip communications preferably with PM operational (as from start of IST) Meaning starting even later?

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE More Lessons learnt ctnd. 13 kA Power converter ground fault on start-up because of water-cooled cable-connections (nipple) touching (electrical) ground. Correction has lead in several cases to water leakage. Torque control of screwed and bolted connections each LS by skilled & trained technicians! Valid for all interventions. 600 A EE FPA signal hardwired as close as possible to switches LS2. Change of motherboard, FPA card and 2 breaker control cards

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58 th MPE-TM October 2, 2014 G.J. Coelingh, TE-MPE-EE Thank you for your attention