Presentation on theme: "6 th April 2010 MP3 weekly summary – issues and follow-up 0v1 M. Zerlauth for the MP3-CCC shift crew."— Presentation transcript:
6 th April 2010 MP3 weekly summary – issues and follow-up 0v1 M. Zerlauth for the MP3-CCC shift crew
Summary of the events during past weeks Circuit(s) Problem Intervention in field Remarks RCO/RCD.A56B2 Tripped again 3 times during the week (total of 8 now!) Not yet done… In all 8 events RCO goes first, FGC buffer indicating an overvoltage trigger (1 st level) RQD/F in S12 and S78Total of 4 (yet unexplained) trips NOAnalysis still ongoing RQT12.R4B1Problem with output stage of power supply DONETrip due to a failure of PC. TRG OUTPUT STAGE POWER SUPPLY RB.A34 / MB.A24R3Heater Power supply discharging DONEProblem appeared on Saturday but repair postponed to Sunday RQX/RTQX2.L5Temperature sensor problemYES, but not fixed?Sensor DXEX02_03L5_TT891A faulty, no repair but only ‘touching’ cables RB.A78Broken micro-switch after opening of EE YESOpening of switches to accelerate current decay after loss of CRYO RQX R8, L8 and L1Tripped when going from stand-by to OFF NOKnown ‘feature’, could maybe be solved through procedure by EPC RQTD/FTune correction currently limited by lower QPS thresholds >= 50A QPS firmware / YESSuperimposition with B2 correction; proposal to increase 50A -> 75A Few additional issues discovered and solved by interventions done during the week Dominating issue is still with unexplained RQD/F trips in S12 and S78
Machine Interlock Systems RCO.A56B2 /RCD.A56B2 RCO.A56B2 (and consequently RCD.A56B2) tripped another 3 times during the week, total of 8 trips now in the past 2 weeks Power supply module of RCO.A56B2 to be exchanged (indicating a trigger through over voltage (1 st level) -> Thursday?
Summary of the RQD/F events so far Event timeSectorCircuit currentPIC historySwitch timestamps Other QPS buffers 30/03 at 08h49m45sS81Ramp with RQF AND /03 at 08h51m17sS12Ramp with /04 at 05h05m03sS12Flat top with 5300A by GPM /04 at 08h43m06sS12Injection, no 750A RQF AND /04 at 18h49m13sS12Standby, no 350A RQF AND /04 at 02h49m48sS78Flat top with 5300A During past days 4 yet unexplained trips on RQD/F circuits of sectors 12 and 78 were observed as shown in the summary below (completed by the two trips on Tue 30 th of March due to the SPS main power supply)
All 4 events have an (almost identical) event sequence, ie ● PIC receives a Quench/FastPA signal from QPS (event sequence in PIC is the typical signature of an event originating within QPS) ● RQD/F trip simultaneously (but for 1 event where the GPM is ‘faster’ than the RQD quench signal) ● RQD and RQF switches open simultaneously and typically 3-5 ms BEFORE the PIC records the quench signal, ie confirming that the QPS quench loop is broken (common QPS quench loop for RQD/F circuits!) ● No indication of changes in Discharge Request Loop, thus trip must be internal to QPS (no other means of opening the switches from outside) ● No other QPS PM buffers (apart from global busbar for 2 events and nQPS buffers which are well after the initial trip and a result of switch OFF of circuits) – Trip of 2 nd QPS board? ‘Typical’ event sequence
The RQD/F.A12 ‘hump’ ● Available data and event sequence seem to indicate triggers to origin within the QPS system, reason after loads of analysis however still unclear ● In sector 12 (where we had 3 oo 4 trips), busbar detector is showing repetitive noise patterns, some peaks up to 1.1V/550ms ● Further investigation with help of QPS experts needed as to the real origin of the trips…