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Proposal for threshold changes Arjan Verweij, TE-MPE

Proposal for threshold changes Arjan Verweij, TE-MPE. IPQ (6 kA) RQTD/F (600 A) HTS leads (13 kA). Arjan Verweij, MPE-TM meeting, 1 Dec 2011. Problem: Tripping because of pick-up in the long circuits, especially in RQ9 and RQ10. Actual setting: 100 mV, 10 ms Needed:

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Proposal for threshold changes Arjan Verweij, TE-MPE

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  1. Proposal for threshold changesArjan Verweij, TE-MPE IPQ (6 kA) RQTD/F (600 A) HTS leads (13 kA) Arjan Verweij, MPE-TM meeting, 1 Dec 2011

  2. Problem: Tripping because of pick-up in the long circuits, especially in RQ9 and RQ10. Actual setting: 100 mV, 10 ms Needed: Factor 2 increase in voltage threshold, or maybe increase in tdiscr. IPQ Arjan Verweij, MPE-TM meeting, 1 Dec 2011

  3. IPQ: Circuits • Calculations and conclusions only hold for the RQ5-RQ10 (consisting of MQM magnets). • The RQ4 (consisting of MQY) is not simulated. • The circuits RQ5-RQ6 operate at 4.5 K, with about 20% smaller current, and are therefore much safer. • No EE Arjan Verweij, MPE-TM meeting, 1 Dec 2011

  4. IPQ: MIIts MIIts dissipation after heater firing is deduced from about 15 quenches in the machine between 2.3 and 5.2 kA on the circuit with the largest inductance (i.e. RQ6 consisting of 2xMQM and 2xMQML). MIIts are then ‘translated’ into an effective decay time constant, and used along with tdiscr, Dth and Uthr in the code QP3 to calculate hot spot temperatures Thot. Arjan Verweij, MPE-TM meeting, 1 Dec 2011

  5. IPQ: Circuit parameters Arjan Verweij, MPE-TM meeting, 1 Dec 2011

  6. IPQ: Quench in magnet, changing Uthr Conclusion: Fully safe up to 4 kA with 400 mV, 10 ms Arjan Verweij, MPE-TM meeting, 1 Dec 2011

  7. IPQ: Quench in magnet, changing tdiscr Conclusion: Fully safe up to 4 kA with 100 mV, 40 ms Arjan Verweij, MPE-TM meeting, 1 Dec 2011

  8. IPQ: Quench in bus adiabatic Resistive joint Conclusion: Fully safe up to nominal current with 400 mV, 10 ms or 100 mV, 100 ms Arjan Verweij, MPE-TM meeting, 1 Dec 2011

  9. IPQ Arjan Verweij, MPE-TM meeting, 1 Dec 2011

  10. Problem: • Tripping because of tune feed-back with currents of about 50-70 A. • Actual setting: • I<50 A: 2 V, 190 ms • 50 A<I<350 A: 100 mV, 190 ms • I>350: to be re-assessed • Needed: • Increase in voltage threshold for currents up to about 80 A. • 2 solutions: • - Increase the limit of 50 A to about 80 A. • Introduce a 3rd threshold, e.g. 300 mV, 190 ms up to 100 A. • If possible, the hot spot temperature during a quench should be kept below 150-200 K RQTD/F Arjan Verweij, MPE-TM meeting, 1 Dec 2011

  11. RQTD/F: Circuit parameters Arjan Verweij, MPE-TM meeting, 1 Dec 2011

  12. RQTD/F: Quench in magnet Arjan Verweij, MPE-TM meeting, 1 Dec 2011

  13. RQTD/F: Quench in bus Hot spot temperatures at 600 A Arjan Verweij, MPE-TM meeting, 1 Dec 2011

  14. RQTD/F Conclusion Both proposed solutions, namely: A. I<100 A: 2 V, 190 ms 100 A<I<350 A: 100 mV, 190 ms B. I<50 A: 2 V, 190 ms 50 A<I<200 A: 300 mV, 190 ms 200 A<I<350 A: 100 mV, 190 ms are fully safe. For 7 TeV operation (when going above 350) the thresholds for I>350 A has to be re-assessed. Arjan Verweij, MPE-TM meeting, 1 Dec 2011

  15. Problem: MSC prefers to detect a quench in the lead in the early flux flow regime, i.e. at the smallest possible voltage. Actual setting: 3 mV, 100 ms Request: 1 mV, tdiscr =100 ms. Needed (in my opinion): 1 mV, tdiscr<several sec Why do we need a discrimination time of 100 ms if the decay time constant is 100 s? Status (to my understanding): We are allowed to use 1 mV, 1 s for a possible CSCM test up to 6.5 kA during the X-mas shutdown. For normal operation next year we should keep our present threshold (3 mV, 100 ms). Amalia will do a test in SM18 in mid 2012 and then give us her green light (or red light) to increase tdiscr. 13 kA HTS leads Arjan Verweij, MPE-TM meeting, 1 Dec 2011

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