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Updated ELQA test procedure

Co-authors: Nuria Catalan Lasheras

Mateusz BednarekGiorgio D’AngeloRichard Mompo

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In brief: Why do we need to update this procedure?

• We introduced a new test (MIC) that involves a HVQ of the quench heaters.o We believe that we need to review the test parameters used in 2009.

• We revised the different scenarios. o Written down the rules that apply during Xmas breaks, shutdowns, partial warm-up of a sector

based on past experiences.

• But the most important...

• The voltage parameters for HVQ test derived from EDMS 90327 from 2004 (LHC-PM-ES-0001 rev. 2.0) are not taking into account the physical configuration of the machine (presence of EE switches opening simultaneously, vicinity of different circuits) and as a consequence the test voltages should be increased significantly! o c.f Nuria’s presentation during MPE-TM meeting of 11 Oct. 2010o C.f H. Ten Kate presentation to Splice Task Force (Oct. 2010): Test voltage too low to guarantee

insulation: Pointed out for the MCS then extended to other circuits

• The plan is to use those new test parameters for the ELQA campaign taking place at the end of this run to find all limitations... and to have time to take corrective actions during LS1, before the run at 7 TeV.

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Samy Chemli circulated a revised version of our test procedure.

• 40 persons were notified and we got very few comments!!!

• Important comment:

o Juan Casas-Cubillos estimated the cost for the

repair/replacement of broken cards consecutive to

ELQA tests at higher voltages to some 1.6 MCHF.

• No strong reaction from the magnet group (except H. Prin

who found a minor inconsistency between 2 tables)?

• No reaction within our group (except Arjan & Reiner)?

We want to make sure that everybody understand the risks

involved by those modifications!

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Ultimate Current

[A]

EE res. [mΩ]

VEE [V]

Vquench [V]

Magnet coils Bus-bars Vmax

[V]

1.2 x Vmax [V]

Tested [V]

Proposed voltage

[V] VEEq [V]

V2q [V]

VGPA [V]

M3

MB 12840 75 482 1300 1782 -- 178

2 1782 2138 1900 1900*

M1/

M2

MQ 12810 7.7 99 200 299 -- 519 519 623 240 360**

MCS 600 700 420 400 820 -- 840 840 1008 480 1000

MCD 600 700 420 400 820 -- 840 840 1008 480 1000

MCO 110 -- -- -- low 400 420 420 504 480 480*

N/N

'

MS 600 700 420 500 920 -- 840 920 1104 600 1100

MSS 600 700 420 500 920 -- 840 920 1104 600 1100

MO 600 700 420 500 920 -- 840 920 1104 600 1100

MQS 600 700 420 300 720 -- 840 840 1008 360 1000

MQTL9 600 700 420 300 720 -- 840 840 1008 360 1000

MQT /L 600 -- -- 300 300 -- 420 420 504 360 500

MQTD/F 600 700 420 300 720 -- 840 840 1008 360 1000

IPQ (1.9K) 5820 -- -- 400 400 -- -- 400 480 480 480

MS/

DS

MQM (4.5K) 4650 -- -- 400 400 -- -- 400 480 480 480

MQY 3900 -- -- 100 100 -- -- 100 120 480 480

IPD 6000 -- -- 500 500 -- -- 500 600 600 600

MQ6 (IP3, 7) 600 700 420 300 720 -- 840 840 1008 360 1000

Undulator 600 700 420 -- -- -- 420 420 504 500 500

IT

IT quads 6000 -- -- 350 350 -- -- 350 420 420 420

IT 600A corr. 600 -- -- 500 500 1000 -- 1000 1200 600 1200

IT 120A corr. 120 -- -- 500 500 1000 -- 1000 1200 120 1200

Table n°6 (p. 23): New proposed test voltages for TP4 and DOC tests

Legend:

• VEE = Ultimate Current * EE res

• Vquench from EDMS 90327

• VEEq = VEE + Vquench

• V2q = Ʃ Vquench for nested magnets

• VGPA is a voltage developped during a Global Power Abort = Max. Voltage seen by a circuit = his own voltage + Max. Voltage on the same cryo. line

Proposed HV test voltages (TP4)

We make the assumption that a quench does not propagate to the busbars!

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Testvoltage

Testduration Limit Vquench Previous Test

voltageProposed Test

voltageTest

duration Limit

[V] [s] [mA] [V] [V] [V] [s] [mA]

Main Dipoles (MB) 600 60 1 1300 2000 2600 60 1

Main quadrupoles (MQ) 500 60 1 200 900 1300 60 1Individually Powered Quadrupoles (MQM, MQMC, MQML) 500 60 1 400 1300 1600 60 1Individually Powered Quadrupoles (MQY) 500 60 1 100 700 1200 60 1Separation Dipoles(D1, D2, D3, D4) 500 60 1 500 1500 1700 60 1Low Beta Quads (RQX) 500 60 1 350 1100 1500 60 1

MIC-W

CIRCUIT type

MIC-C

Table n°10 (p. 27): New proposed test voltages for MIC tests

Reminder: MIC test involves a HVQ test of each QH vs “Coil+GND”.

We revised the test voltage values. The calculation is as follows:

U = 1.2 x (VDQHDS + Vquench) = 1.2 x (900 + Vquench)

Major HW modification would be needed to be able to test above 2000 V.

It is foreseen to produce specific HDSs for Separator Dipoles with lower voltages

Proposed HV test voltages (MIC)Proposed HV test voltages

QHs actually see 450 V but in case of an internal failure of the HDS, they may see 900 V .

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Conclusions

• Some components may not wistand those test voltages (ex: cryo. cards).o A stock of spares need to be prepared…

• Several circuits have never been tested to those voltages (but, in some case, in SM18,

single magnets were tested at higher voltages).o We want to identify weaknesses before the warm-up. In some cases, we don’t have any

spares (ex: Inner Tripplets).

• Breakdowns propagating along a circuit may damage other components such as: QPS controllers, TT sensors...

• Redesign HVQ crates to reach 2600 V ?

• Is it planned to modify the extraction resistance of RQD and RQF circuit during LS1?

• Do we need to put our American and Japanese colleagues in the approval list?

… Some other limitation/implication, that we are not aware of, may exist?

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Thank you for your attention!

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Spares slides

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Exceptions:

• The proposed voltage is in most cases taken close to 1.2 times Vmax. However, we have made exceptions in some cases:

• *The case of the dipole line is special, as the maximum voltage assumed already on [9] is due to a possible fault on a pole of a power converter. No safety margin is taken however in this case. The safety margin is also reduced for the MCO circuit.

• **For the MQ circuit, we recommend to test them at the 1.2 times VEEq to qualify the circuit under the worse conditions seen by the coil. The required voltage difference between bus-bars in line M1/M2 will be seen during the test of the spools and correctors done this time at a higher value. This means that partial test only on the MQ lines is not allowed. All HVQ tests have to be done in all the circuits of the same line, namely M1/M2.

• For MCDO, the highest constraint comes from energy extraction of the MCD circuit. There are no values of voltage developed during a quench for this magnet but we assume the voltage is very low given the low nominal current.

• Values in red are higher than the withstand voltage currently applied.

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Test parameters for dipole magnets tested in SM18

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Test parameters for SSS magnets tested in SM18

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Test parameters for SSS magnets (500 series) tested in SM18 (1/2)

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Test parameters for SSS magnets (500 series) tested in SM18 (2/2)

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Test parameters for S4 magnets tested in SM18 (1/3)

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Test parameters for S4 magnets tested in SM18 (2/3)

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Test parameters for S4 magnets tested in SM18 (3/3)