BNL FNAL LBNL SLAC LQ DS VideoMeeting May

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BNL - FNAL - LBNL - SLAC LQ DS Video-Meeting May. 23, 2007 Long

BNL - FNAL - LBNL - SLAC LQ DS Video-Meeting May. 23, 2007 Long Quadrupole Quench Protection Giorgio Ambrosio OUTLINE: • LQ Quench protection • Spikes recorded during TQS 01 c test • Comparison with real quench signals • Plan LQ DS video Mtg – May. 23, 2007 LQ Quench Protection – G. Ambrosio

TQ/LQ conductor parameters Parameter N of strands Strand diameter Bare width Unit mm mm

TQ/LQ conductor parameters Parameter N of strands Strand diameter Bare width Unit mm mm Value 27 0. 700 10. 050 Bare inner edge thickness Bare outer edge thickness Keystoning angle Radial insulation thickness Azimuthal insulation thickness Copper to non-copper ratio Copper RRR mm mm deg. mm mm - 1. 172 1. 348 1. 000 0. 125 0. 89 100 LQ DS video Mtg – May. 23, 2007 LQ Quench Protection – G. Ambrosio 2

Parameter N of layers Unit Magnet parameters- LQ - 136 cm 2 29. 33

Parameter N of layers Unit Magnet parameters- LQ - 136 cm 2 29. 33 m 3. 6 N of turns Coil area (Cu + non. Cu) Length 2 Jc(12 T, 4. 2 K) = 2400 A/mm 2 4. 2 K temperature Quench gradient T/m 223. 49 Quench current k. A 13. 47 T 11. 59 m. H/m 4. 1 k. J/m 372 Quench gradient T/m 240. 57 Quench current k. A 14. 57 T 12. 48 k. J/m 435 Peak field in the coil at quench Inductance at quench Stored energy at quench 1. 9 K temperature Peak field in the coil at quench Stored energy at quench LQ DS video Mtg – May. 23, 2007 LQ Quench Protection – G. Ambrosio 3

LQ Quench Protection • Quench. Pro Input – Magnet parameters: • Conductor: • Total

LQ Quench Protection • Quench. Pro Input – Magnet parameters: • Conductor: • Total energy: TQC 01 x 3. 6 m coils TQ cable (Jc 2400 A/mm 2) 1. 3 MJ @ 4. 4 K • Code and input validation – Geometry, inductance, mat. prop (QLASA/Opera/ROXIE/TQC 01): Done – Effect of changes to quench propagation routine: Very small • Comparison with TQs data – TQ tests set MIITs limit: in progress • Quench protection parameters (aggressive) – Detection time: 5 - 10 ms – Heater delay time: 10 - 15 ms LQ DS video Mtg – May. 23, 2007 based on TQs LQ Quench Protection – G. Ambrosio 4

TQs Heater Delay & Detection Time • Heater delay time: t ~ 10 ms

TQs Heater Delay & Detection Time • Heater delay time: t ~ 10 ms close to quench plateau; t < 15 ms at I = 62% Issl • Detection time: 3 - 11 ms during TQS 01 c training – Flux jumps up to 600 m. V with MJR cable msec TQC 01 TQS 01 c LQ DS video Mtg – May. 23, 2007 LQ Quench Protection – G. Ambrosio TQC 01 protection heater studies by using spot heaters to initiate the quench. 5

MIITs Limit • Impact on quench performance of high -MIITs quenches (TQS 01 c)

MIITs Limit • Impact on quench performance of high -MIITs quenches (TQS 01 c) • • • + 4% after 8 MIITs - 2. 9% after 8. 1 MIITs - 7. 4% after 8. 7 MIITs - 18. 4 after 9. 5 MIITs Small bumps at 7. 5 MIITs • During TQC 01 test, one QI vs. T measurement I: 5000 A , LQ DS video Mtg – May. 23, 2007 QI: 9. 05 MIITs, Peak Temp: 340 K LQ Quench Protection – G. Ambrosio 6

MIITs and Voltage at quench current Dump = 60 m. W Detection time =

MIITs and Voltage at quench current Dump = 60 m. W Detection time = 5 ms Heater delay time = 12 ms 100% coverage Hot Spot Heaters 7. 6 4. 6 MIITs Turn-turn Ground 55 V 4. 4 K 1. 9 K LQ DS video Mtg – May. 23, 2007 High MIITs at 1. 9 K Voltages OK 75% coverage 50% coverage 7. 9 4. 9 8. 3 5. 3 MIITs 446 V 65 V 459 V 84 V 536 V 8. 4 4. 9 8. 7 5. 2 9. 2 5. 7 MIITs MIITs 72 V 489 V 85 V 520 V 109 V 615 V LQ Quench Protection – G. Ambrosio 7

How to get margin for safe LQ test? Y – 100% heater coverage with

How to get margin for safe LQ test? Y – 100% heater coverage with 4 independent circuits per coil • to be ~safe in case of failure (easier heater manufacturing, see LR) Y – Shorter detection time and/or heater delay time? • Heater design, and QP system upgrade LQ quench protection ? – Larger dump resistance? with TQ-like coils is • Hard at 1. 9 K: with 60 mohm we have ~ 1 k. V at the leads challenging but doable at • Possible at 4. 5 K: could go up to 75 mohm 4. 5 K N – Lower RRR in order to have shorter detection time? • …risky… Y – Improve/upgrade VMTF Quench Detection System: • Low threshold * small time: in order to avoid trips induced by spikes • Capability of changing QDS threshold easily during tests LQ DS video Mtg – May. 23, 2007 LQ Quench Protection – G. Ambrosio 8

Needs for LQ QP • • • Four independent circuits for protection heaters Change

Needs for LQ QP • • • Four independent circuits for protection heaters Change dump resistance at 1. 9 K? Design LQ protection heaters Easily changeable detection threshold Develop smart quench detection to avoid spikes with low threshold? – – Time Voltage slope Spike recognition Current depending threshold LQ DS video Mtg – May. 23, 2007 LQ Quench Protection – G. Ambrosio 9

Last trip by flux jump Threshold was 600 m. V LQ DS video Mtg

Last trip by flux jump Threshold was 600 m. V LQ DS video Mtg – May. 23, 2007 LQ Quench Protection – G. Ambrosio 10

Half coil LQ DS video Mtg – May. 23, 2007 LQ Quench Protection –

Half coil LQ DS video Mtg – May. 23, 2007 LQ Quench Protection – G. Ambrosio 11

 • 4 coils LQ DS video Mtg – May. 23, 2007 LQ Quench

• 4 coils LQ DS video Mtg – May. 23, 2007 LQ Quench Protection – G. Ambrosio 12

Quad 2 = Coil 8 segments LQ DS video Mtg – May. 23, 2007

Quad 2 = Coil 8 segments LQ DS video Mtg – May. 23, 2007 LQ Quench Protection – G. Ambrosio 13

VSDS NO quench Quench NO quench LQ DS video Mtg – May. 23, 2007

VSDS NO quench Quench NO quench LQ DS video Mtg – May. 23, 2007 LQ Quench Protection – G. Ambrosio 14

Quenches Quench 51 - I = 9600 A, T = 4. 5 K, Rate

Quenches Quench 51 - I = 9600 A, T = 4. 5 K, Rate = 20 A/s Time for decision should be less than 2 ms LQ DS video Mtg – May. 23, 2007 LQ Quench Protection – G. Ambrosio 15

New QDS … in progress FPGA-based system: • • It is firmware running in

New QDS … in progress FPGA-based system: • • It is firmware running in a PXI board, and it does not depend on an operating system such as Vx. Works, Linux, or Windows. Note that you already depend on this approach for VMTF quench detection and protection: in the current VMTF system, the Quench Logic Module (QLM) logic is programmed in firmware, and you depend on this module to perform properly to protect a magnet. This can really simplify the complexity of the system, as we have seen with the Stand 3 example. It can also make it easier to implement the type of adaptive logic we discussed during the meeting. Of course we need to discuss what level of redundancy or analog backups we need for risk mitigation. LQ DS video Mtg – May. 23, 2007 LQ Quench Protection – G. Ambrosio 16

Appendix LQ DS video Mtg – May. 23, 2007 LQ Quench Protection – G.

Appendix LQ DS video Mtg – May. 23, 2007 LQ Quench Protection – G. Ambrosio 17

Quench Pro I • Analytical code • Adiabatic approximation • Temperature computed from Quench

Quench Pro I • Analytical code • Adiabatic approximation • Temperature computed from Quench Integral – Field is constant (average); different values for hot spot and bulk – Epoxy included in QI – Strand non_Cu = 76% Nb 3 Sn, 33% bronze (by Arup) • Longitudinal propagation by QP velocity • Quench starts under heaters – after detection time + heater delay time • Temperature is uniform (given by QI) in normal zone of each cable – Different between Hot-spot and bulk LQ DS video Mtg – May. 23, 2007 LQ Quench Protection – G. Ambrosio 18

Quench Pro II • Current decay – Magnet can be switched to a dump

Quench Pro II • Current decay – Magnet can be switched to a dump resistance (after detection) or leads are short-circuited – Current decay is computed based on the instantaneous time constant (computed from the growing resistance and the inductance) – Inductance is computed based on position of each turn (inductance matrix) • Voltages – Computed based on current, resistance, d. I/dt, inductance matrix, (at d. I/dt max) – Turn to ground – Turn to turn LQ DS video Mtg – May. 23, 2007 LQ Quench Protection – G. Ambrosio 19

Sensitivity to Quench Prop. simulation • New quench propagation routine in Quench. Pro to

Sensitivity to Quench Prop. simulation • New quench propagation routine in Quench. Pro to better fit LQ magnet features Very small effect! Temperature vs. MIITs tuned on TQC 01 Dump = 60 m. W Detection time = 8 ms Heater delay time = 15 ms 100% coverage 75% coverage 50% coverage 412 K 108 K Hot spot Heaters 449 K 504 K 121 K 143 K OLD routine 138 K NEW routine 1. 9 K 412 K LQ DS video Mtg – May. 23, 2007 108 K 441 K 118 K 490 K LQ Quench Protection – G. Ambrosio 20