Powering Group of Circuit Doubts and proposals of the procedure reviewing team (Gianluigi, Rob, Sandrine, Matteo, Boris) Ref document: LHC-MPP-HCP-071

PGC.1 Study the electromagnetic coupling between circuits, devoting special attention to the QPS detectors. This group of tests is done at powering subsector level. PGC.2 Validation the performance of the DFB and current leads when all the circuits of one DFB are powered as well as the long term behaviour, at sector level, by using an overall current profile representative of a machine operation configuration. It is also a last check of the superconducting splices. – The PGC1 and PGC2 tests should be performed with all the circuits ramping at the acceleration and ramp rates achieved during the commissioning. These will possibly match the nominal acceleration and ramp rates. PGC.3 Validation the squeeze functions of the machine. PGC.4 Final machine validation by powering all sectors in unison Powering Group of Circuit

PGC1 for the ARC of the : GPM inj On RB,RQD/F,IPQ 2: Nom 3: Int. 4: Nom 5: EMC during flat top 6: EMC during ramp 7: SPA on RQs 8: Loss of Cryo Maintain

The functionalities are checked in the PIC2 tests. The link Cryo-Maintain/PIC is checked in PIC2 for each circuit Proposal: skip because redundant. PGC1: Arc- PIC functionalities 1: GPM inj On RB,RQD/F,IPQ 9: Loss of Cryo Maintain

PGC1: Arc – Cycle at nominal This test is performed in order to verify any electromagnetic coupling among circuits. The list of QPS that triggered should be determined and the QPS signals should be verified in order to understand whether a quench occurred. Is it necessary to do it taken into account that the following tests should allow to verify that as well.

PGC1: Arc - Interm. and Nom 3: Int. 4: Nom 4: Provoked quench on a RB

PGC1: ARC – EMC for 600A EMC among 600A or 600A vs. mains? Do we really need to do 2 different tests? Shall we keep only the most conservative? (2 nd ) Once (If) an EMC is found, which are the actions to be taken? Triggering sequence (Rob): – determined by the current decay rate at fast power abort – 600A circuits divided into two groups as N-line correctors or spool pieces. 5: EMC during flat top 6: EMC during ramp Trigger Seq GroupCircuitQuench expected Initial decay rate (A/s) 1Spool piecesRCSNo3400 2RCOmaybe350 3RCDmaybe13.5 kA/s 1N lineRQTL11No200 2RQS (2-magnets)No450 3RQTL9 (in 3 and 7)No (?)600 4RQT12,13No770 5RSF1/2, RSD1/2Yes RQTD/FYes1200 7RSSYes1275 8RQSYes1900 9RO D/FNo kA/s

What is the aim of this test? PC functionalities test? why do we do this test for RQs and not for the RB? Done by removing the permit to powering PGC1: ARC - SPA on RQ 7: SPA on RQs

PGC1: Matching Sec 2: FPA in a Separation dipole 3: SPA in a IPQ 1: Nominal 4: Loss of Cryo Maintain

do we need it? – DFB circuit coupling checked in the following step (FPA) – DFB Heat Load test? Also in the next…or even in PGC3 (squeezing tests) PGC1: MS – Cycle at nominal 1: Nominal

The fast power abort of the superconducting dipole will produce a fast power abort of all the circuits in the corresponding powering sub-sector. – Test performed to verify the correct operation of the GPM? These tests are likely no more necessary because there is already a test at 0/I_min_op current during the PIC Global protection mechanism test during the HW commissioning of each circuit – Verification of the electromagnetic coupling among the circuits sharing the same DFB?. The list of QPS that triggered should be determined and the QPS signals should be verified in order to understand whether a quench occurred. How many circuits can be coupled? PGC1: MS – FPA on IPD 2: FPA in a Separation dipole

To be performed in the matching sections containing cryostats that have several main circuits fed by a DFB. These are those fed from a DFBL (it is considered that they belong to the same cryostat) or by a DFBM that contain more than one main circuit (e.g. D2Q4 or D4Q5 cryostats). However all the circuits of the matching section are included in the test. The circuit going through the slow abort has to be specified for each matching section. In case it is a MQM/MQY circuit, the power permit must be removed only in one of the converters leaving the other ON. Why that? Do we need such test? List of parameters to be recorded: The list of QPS trips PGC1: MS – SPA on a IPQ 3: SPA in a IPQ

As for the arc… PGC1: MS – Loss of cryo maintain 4: Loss of Cryo Maintain

The second step is no more needed The ramp down after the last step should be performed in steps with 2-3 plateaus. PGC2: all the circuits Obsolete

PGC3 and PGC4 ABP working on it (S. Fartoukh and M. Giovannozzi) – first draft in within following weeks.

Once upon a time there was a MTF step/field called MPP OK for each circuit which, once filled as “ok”, determined the start of the powering test of that circuit. Those MTF field are still there, but largest part empty. Accessing MTF is heavy if done per circuit! This year: MP3_OK sequence requiring an MP3 expert signature and an automatic fill of MTF field. AOB: MP3 OK for powering