The QPS I ndividual S ystem T est Overview

1. The QPS Individual System TestOverview R. Denz, TE-MPE-EP

2. Outline • Two presentations on QPS-IST today: • Overview (now) • QPS-IST for the nQPS (Jens) • Why one needs an individual system test? • The scary part … • What needs to be tested? • The frightening part … • Timeline • The desperate part … • Safety aspects • The important part – don’t sleep then! • Documentation • The obligatory part …

3. Why one needs an individual system test? YOU ARE HERE • LS1 = substantial upgrade & revision of QPS (and LHC …) • Main dipole protection systems (yellow racks) • R2E related upgrades: • Relocation in point 1 & 5 • IPQ and 600 A protection hardware upgrade • QPS firmware revision & upgrade (DAQ systems + protection systems) • QPS supervision upgrade (field-bus, gateways, libraries …) • QPS instrumentation • Almost all cables have been accessed • New cables & connectors, re-routed cables • UPS upgrade • … • Post LS1 test & commissioning = qualification of a new machine

4. Why one needs an individual system test? • The QPS-IST after installation in the LHC is the last series of functional tests prior to the powering tests. It has been preceded by a vast test campaign starting already at the manufacturer’s premises; it will be succeeded by the ELQA tests @ cold and the quench heater discharge tests (part of powering tests). • The principal objective is to guarantee the protection capability of the system. • As the ELQA tests, the QPS-IST cannot identify all possible faults! • Complete set of possible faults not known! • Some faults, e.g. related to improper assembly of cables and connectors may “sleep” for quite a long time … • The majority of the faults revealed during the functional tests in 281 were related to cables & connectors; some faults were most likely caused by the transport and handling of the yellow racks ( be prepared …). • A fraction of the yellow racks (“the backlog”) has been submitted to major manipulations after functional testing. In consequence some tests like the quench heater power supply discharge need to be repeated in the tunnel; fortunately these tests can be performed within the nQPS qualification.

5. What needs to be tested? • The QPS zoo – a few figures: • Not counting the LHC energy extraction systems, there are 36412 items to be tested and commissioned after LS1. • Many requirements to start the tests as the QPS systems depend on many services like, • Transport services • Controls infrastructure (field-busses, gateways, servers, databases, timing …) • UPS powering • …

6. Example: test sequence for DYPB w/o nQPS

7. What else needs to be tested? • Protection units for IPQ, IPD protection after revision and upgrade • 68 protection units housing up to 15 circuit boards each • Instrumentation cabling for the IPQ circuits has been modified to achieve better EMC immunity especially during power outages • Protection systems for inner triplet protection • Relocation of systems currently installed in UJ14,16, 56 within R2E upgrade • Only 8 systems (+ IT corrector protection) but a catastrophic failure could have very serious consequences for LHC operation (no IT spares!) • Protection systems for 600 A • Most sophisticated quench detection systems in LHC • 114 protection units housing up to 17 circuit boards each • 28 units to be equipped with newly developed radiation tolerant quench detection systems • Real individual system tests, i.e. an individual QPS expert tests a system …

8. Timeline • QPS-IST for the main circuits will start on April 1st and finish August 14th • Marathon, not sprint, followed by another marathon … • Many parallel activities during these period of time • Functional tests in 281 & QPS labs • CSCM (requires substantial support by QPS experts!) • QPS equipment upgrades not related to main circuits (IPQ …) • Schedule is very ambitious and does not contain any contingency • For all sectors where CSCM tests are being performed a subset of the QPS-IST needs to be repeated; the CSCM itself must not be performed w/o a successful test of the nQPS and the QPS interlock loops. • Accounted in planning for sectors where CSCM has been approved • In case of interventions after the QPS-IST all or a subset needs to be repeated! • Major modifications and upgrades after QPS-IST to be avoided!

9. Safety aspects – general rules • QPS equipment must not be accessed, serviced or disconnected while any superconducting circuit in the same powering subsector is powered. • QPS equipment must not be accessed, serviced or disconnected without prior authorization by the responsible person. • Quench heater discharge power supplies type DQHDS must not be powered without prior authorization by the Chargé de Consignation CC. • Quench loop controllers type DQQLC must not be powered and connected to the current loops of circuits RB, RQD and RQF without prior authorization by the Chargé de Consignation CC. • Any equipment going to be uninstalled and removed from the LHC tunnel or underground areas must checked and cleared by the CERN radioprotection (RP).

10. Safety aspects – specific risks I • Transporting and handling of QPS systems • When handling QPS equipment appropriate safety equipment has to be used; this concerns especially personal protection equipment like gloves and safety shoes. • Some of the equipment (not talking about EE systems …) is relatively heavy e.g. mDYPB = 130 kg, mDQHDS = 25 kg • Some of the QPS crates and racks are featured with sharp edges as the word “deburr” is not known to all manufacturers of mechanical enclosures. • QPS internal interlock loops • The QPS interlock loops are isolated from common ground and feed with maximum voltages up to 100 V. • Quench detection boards • All quench detection boards are connected to the live parts of the LHC superconducting circuits. With powered superconducting circuits one part of the circuits board will always be on the circuit potential, which may significantly higher than the common ground potential.

11. Safety aspects – specific risks II • 230 V mains powering • All QPS racks are powered by two 230 V mains connections fed by UPS systems. • The bolted protective earth connection PE must be established prior to the powering of racks DYPB and DYPQ! • Despite the general precautions, there is a specific risk for protection units type DQLPU B (MQ protection inside rack DYPQ = “short yellow rack”).

12. Safety aspects – specific risks III • Quench heater discharge power supplies type DQHDS • The capacitor bank of the quench heater power supply consists of six Aluminium electrolytic capacitors with a total capacity of 7.05 mF with a nominal charging voltage of 900 V. The stored energy is 2.9 kJ. During a normal quench heater discharge the peak current is 70 A but the power supply is not limited and in case of a wrong manipulation it may deliver a peak currents in the order of some kA. In consequence precautions have to be taken for any manipulation with this type of power supply. • Disconnection of the magnet connector on racks DYPQ and DYPB • ATTENTION: THIS MUST NEVER BE DONE WITH POWERED QUENCH HEATER DISCHARGE POWER SUPPLIES! • This is of particular importance as during the QPS-IST dummy loads will be used for discharge tests! • In case of the nQPS testing be aware that the DQHDS and the trigger source are not located in the same rack! • Service & repair of quench heater power supplies only by trained personnel!

13. Safety aspects - documentation • Basic document has been compiled already some time ago but not yet distributed • A short TE-MPE internal training course is in preparation • First sessions to be scheduled beginning of April • These sessions do not replace the mandatory official courses but are required for newcomers to access QPS equipment in the LHC.

14. Documentation • Basic procedures to completed – draft copies can be found on • \\CERN\dfs\Workspaces\q\QPS_TEST • EDMS version later as content still may change frequently • Test progress will be reported on dedicated QPS workspaces on DFS: • \\CERN\dfs\Workspaces\q\QPS_TEST • \\CERN\dfs\Workspaces\q\QPS_INSTALLATION • QPS supervision data can be found at the usual places (TIMBER, PM …) • MTF, EDMS, MMP … regarded as not suitable to document these types of tests • WARNING: • All information currently stored in EDMS and referring to QPS equipment managed by TE-MPE-EP is obsolete and not valid for LHC commissioning and operation after LS1. • Ways to be identified to update this information. • Current access rights are bewildering … General overview ends here – next some information on how to test the nQPS!