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Magnets & QPS towards operation

N. Catalan Lasheras on behalf of MPP and QPS teams

LTC extended meeting 3 March 2008

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How to operate up to 8 sectors together?

How do we operate during the hardware commissioning

Recovery after a quench: how much time does it take? Is expert intervention required? How can this be improved?

Equipment folder: tests results, handling of non-conformities, performance below specs, machine as commissioned vs. machine as nominal

How will we operate after hardware commissioning

Alarms/signals/SW available in CCC

Piquet/Experts availability

How to operate up to 8 sectors together

OUTLINE

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Procedures for the powering tests are defined/revised by MPP, QPS, PO, CO

A series of tests at different currents checking the full functionality of all systems

From each test we may extract and store data (in MTF)

Each test is approved by at least an expert group (PO, QPS, PIC or MPP)

In CCC an automatic software operated by the EiC runs the tests as defined by the hardware commissioning coordinator.

The circuit is commissioned at the end of the tests and released for powering after the off-line analysis has been done

How does it work during hardware commissioning

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A QPS team is formed by two operators and a team leader. Can ensure two fronts simultaneously.

Four QPS teams in the CCC. Two shifts. Four fronts. Backed up by 4-5 coordinators.

Staffing is not assured from May

Two MPP (magnet performance panel) experts in the CCC for all fronts. Manpower may become critical with several sectors.

An energy extraction (EE) field team supervising part of the tests.

Teams on call to diagnose electrical faults.

How does it work during hardware commissioning

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5

Recovery after a quench (I) . Energy extraction

In case of a quench always in the shadow of cryogenics recovery

In case of extraction for other reasons (e.g. FPA request) the minimum recovery time will be determined by the DQR cooling

Quadrupole threshold

Dipole threshold

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Recovery after a quench (II). Analysis

Analysis after a quench

– Heater discharged ok?

– Energy extraction ok?

Quench origin

– Magnets, current leads, bus bar

– PC or QPS trigger

Very fast quench propagation, re-quench.

– New phenomena not observed in SM18 or in the string.

– Not understood yet.

– More may come

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Manufacturing test folders

The sequencers fills automatically the MTF steps and sends the data taken on-line

Non conformities are open off-line

Off-line data is entered after analysis

After all steps are finished, analysed and ok, the circuit is released for operation

Still working on sector 4-5...

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All NC opened in EDMS and attached to circuits

NC in a sector opened during HW are accessible from the HC page

When the circuit can not be powered, the leads are grounded and the PC not connected or condemned

When the circuit can only be powered up to a level of current, hardware and software limited

Non-conformities

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Circuits in LHC will be commissioned to what is called I_PNO.

This current is a parameter that may be different from the LHC design report.

How to prevent accidental powering above this current?

Hardware and software limits can be set in the power converter.

6 KA and 13 kA converters can be limited at any value

May be wise to use these values when defining I_PNO

How to avoid powering above the allowed limits?

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Review of the powering procedures

We are not repeating the same tests for different energies...not very efficient...

Each functionality of the system is tested only once at the optimum current level.

A circuit is commissioned only after tests called PNO are done successfully.

We can shorten PNO by decreasing the energy (avoiding quenches and testing with degraded cryogenic conditions) but not by cutting tests.

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QPS will re-arm automatically after a quench as well the DAQ for the EE (feature already enabled for individual MB and MQ protection, under test for the rest)

EE systems can be closed via macros allowing to close all switches of a sector or all of the LHC. AB-CO promised to have this feature available for sector 5-6.

Expert intervention only required in case of faults. The system can be controlled by the LHC operator entirely via the PVSS supervision using a restricted (=safe) command set.

The POWER_PERMIT status of each circuit is transmitted to LASER (not enabled for commissioning). Supervision will allow then to identify the element of the circuit provoking the alarm

– RED = quench/activation of EE system,

– GREEN = logging mode = fully operational,

– ORANGE = POWER_PERMIT lost.

QPS in operational mode

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Analysis of the QPS and EE systems after a quench could be automatic or assisted by defining tolerances.

– Heater discharge voltage time constant and minimum value.

– Extraction resistor voltage maximum value and time constant.

Trips of the PC can be diagnosed using the PVSS system

Some analysis still needed

– Trip of the QPS system

– Origin of the quench

– Quench propagation

Magnets trained to “nominal current” are not expected to undergo training quenches. Any quench is then exceptional.

Magnets in operational mode

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Software available

PVSS supervision.

Post mortem analysis.

TIMBER.

Analysis software

– Currently used for analysis of hardware commissioning tests. Not always useful for operation

– Set of expert analysis tools currently under construction. Always based in PMS and Timber.

– EiC aware and knowledgeable.

– Availability and suitability to be decided.

AB/CO writes and maintains the software.

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Piquet service

A piquet service is being discussed as of this month

It could regroup the experts from

– QPS Quench protection and energy extraction

– ElQA electrical quality assurance, diagnostics and repairs

– Current leads, disconnection and re-connection.

Training on the other functions will be done during hardware commissioning

Start of the piquet service only after hardware commissioning if requested.

MPP and QPS experts will be available in the CCC until the end of commissioning. Two shifts.

Assistance of MPP for quench analysis and recovery during beam commissioning and beyond is being discussed within the AT department.

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How to run all 8 sectors together

After commissioning of the circuits, functionality and availability are guaranteed. Few events expected.

Very successful run during PGC tests in sector 4-5!

Question should be addressed to CO and OP?

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Hardware commissioning still ongoing. We do not have all the answers yet.

After the circuits are commissioned few events are expected.

Recovery from a quench should be automatic. The time to recover can be estimated very accurately.

Supervision software will indicate the faulty circuit/system. PMA and Timber can be used for analysis.

Experts will be in CCC till the end of hardware commissioning. Some experts will be required in beam commissioning and beyond.

All non-conformities in MTF and visible trough different tools.

Circuits should be locked to commissioned currents.

Powering of a group of circuits is the first step trough operating LHC.

Thanks: K. Dahlerup Petersen, R. Denz, S. Le Naour, A. Siemko, Y. Thurel, L. Walckiers

Conclusions

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Post-Mortem Analysis

One file per event per system and per subsystem with the time stamp

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PVSS supervision

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Timber

Continuous loogging of data for all systems (slower rate).