1. New HV test specification for the LHC N. Catalan for the EI section

2. The current specification EDMS 90327 from 2004 (LHC-PM-ES-0001 rev. 2.0) Refers to equipment tests from manufacturing to installation in LHC – Operation conditions define the lower voltage – Apply decreasing voltages through manufacturing Only single circuits vs. ground are considered

3. The voltage to ground for each circuit Two different sources of voltage during operation – Energy extraction at maximum current U=RI – Quench voltage from simulations Either/or for all circuits but for dipoles Safety factor 1.2 applied – Except for dipole circuit Missing RCO 2xV+500 I max x R EE 1.2xV

4. From ElQA EDMS 788197 (2008)

5. Insulation tests during TP4-e tests Different classification from EDMS 90327 Different tests for air cooled leads 1.each circuit tested at a lower voltage one by one versus all other circuits and ground. 2.all circuits of one chimney are tested together at higher voltage level vs ground.

6. RQ vs Spools M1/M2 lines and M lines run along together General protection will run down all of them at the same time

7. Line N circuits Bus-bar run together along the same cryogenic line Metallic braids already gave insulation problems MQT, MQTL, MQS, MSCB with energy extraction MO, MQM with no EE Monday Morning Meeting : 3rd of May 2010

8. A. Perin AT-ACR, 8 Spool busbar routing inside DFBAs Busbars in lines M1 & M2 Busbars merged with line N All 600 A busbars in the same duct Correctors Spool Bundles of n x 4 busbars

9. New voltage to ground values Which electrical circuits have bus-bars running in the same cryo-line? Only circuits whose voltage is coming from EE should be taken into account. Nested circuits Maximum operation voltage x1.2

10. Maximum operational voltage against any neighboring circuit Tested circuit vs. all others + ground Voltage level proposal

11. HV tests with new voltages need to be implemented prior to cool-down in 2011/2012 RCO/RCB Lemo connector insulation weakness – Will be inspected in the next technical stop – Repair during the Xmas break? Tests of the two bus-bars of RQ? – Implemented during the assembly in the long shutdown in 2012 – Is it possible to interrupt the circuit? Practical considerations

12. Magnet instrumentation check – Local measurement at warm and cold – Continuity and resistance of diagnostic Vtaps – Resistance and insulation of QH – QH against coil & ground ElQA test procedure needs to be updated – Can be done at the same time as HV qualification for the magnet MIC tests introduced during 2009

13. Quench heaters vs. ground Not specified in the note Minimum 2x450+500 = 1400 for most circuits Voltage on the coil during quench added to this value Not taken into account in US magnets during manufacturing Needs to be reviewed

14. Where is it coming from?

15. Tests in SM18 at cold Reception tests in b181(at warm) for US magnets Minimum voltage retained QH/coil vs. ground values? MIC proposed HV values

16. ElQA test procedure 788197 to be rewritten and reissued Higher values to be applied almost in all correctors RQ(M) and RQ circuits MIC test to be added Hardware modifications in DFB chimneys to remove limitations to be implemented – During Xmas stop – During long shutdown Conclusions

17. Machine will be emptied Three days cooling tower cleaning will stop active cooling on DFBs All DFBs SAM and SC links will warm up above 120K According to A. Perin that will mean a full thermal cycle What parts of ElQA need to be redone? Xmas break ElQA tests

18. From ElQA test procedure

19. ElQA Only TP4e tests HV in the arc – One week per sector for a team of 2-3 people – Enough resources in house with the eventual help of other sections – Two sectors in parallel. – To be fitted in the schedule Full TP4e and MIC in the SMA magnets