Special powering test proposals for LS1

Daniel Egede Rasmussen TE-MPE-PE 1

Special powering test proposals for LS1

ByDaniel Egede Rasmussen, Scott Rowan

& Emmanuele Ravaioli

Thanks toArjan Verweij, Knud Dahlerup-Petersen, Gert-Jan Coelingh

06/12/2012

TE-MPE Technical Meeting 06-12-2012

Change of the EE resistor value in an RQTD/F circuit&

Fast power aborts in 600A circuits


Change of the EE resistor value in an RQTD/F circuit

06/12/2012

1st proposal


Motivation

06/12/2012

Principal drawing of RQTD circuit.

• When a fast power abort is triggered at nominal current (550 A) a voltage drop of 300 V is reached across the EE resistor.

• The dI/dt in the magnets when the EE resistor is switched in introduces high enough AC losses to cause a quench-back.

• Both ‘high’ voltages and quench-backs stresses the magnets and seems unnecessary. (Hotspot temperature reached in current configuration: 101 K).

• A lower EE resistor value would lower the voltage drop and avoid quench-backs.

Why change something that works?


Motivation

06/12/2012

• The RQTD circuit has been simulated in PSpice and the hotspot temperature has been found by running QP3 with the MIITs from the PSpice simulation.

• No quench-back has been added to the simulation, making it a worst-case hotspot temperature.

• Voltage drop can be reduced without a significant increase in hotspot temperature in the quenching magnet.

Voltage drop and hotspot temperature


Motivation

06/12/2012

Events:FGC 51_self 110219-010757.080_RPMBB.UA67.RQTD.A67B1FGC 51_self 080827-145831.100_RPMBB.UA23.RQTD.A12B1FGC 51_self 080422-115213.960_RPMBB.UA63.RQTD.A56B2FGC 51_self 110214-192759.320_RPMBB.UA27.RQTF.A23B2

Quench-back and EE resistance

Current decay in magnets simulated in PSpice


Test description

06/12/2012

• Ad extra EE resistors in parallel

• 2 spare resistors - 3 combinations

• FPA’s at a couple of current levels to determine quench-back limit.

• Use DCCT for current measurements

• Use external measurement devise for voltage measurements


Test description

06/12/2012

Resources

• 2 spare 600 A EE resistors (0.7 Ω)

• Cabling and connectors (bolting or clamps)

• Measurement equipment (Scope or measurement board)

• Test time: Connection and setup of measurement equipment in tunnel 3 times and 10 FPA’s ̴�with a recovery time of 15 min (est. test time of 1 day) ̴�


Test description

06/12/2012

Safety

• Machine safety worst-case:

– Worst-case is a quench at nominal current (550 A) with 0.233 Ω EE resistor and no quench-back.

– According to simulation in QP3 with current decay from Pspice simulation the worst-case hotspot temperature for the test is 130 K compared to 101 K at normal operation (without quench-back: 115 K ).

• Personnel safety:

– Due to limited space additional “high voltage” EE resistors have to be placed outside PC cabinet.


Test description

06/12/2012

When?

• Can be done in any RQTD/F circuit.

• Circuit has to be cold.

• Access to the tunnel has to be allowed.

• The estimated test time of 1 day, makes it hard to squeeze in during operation.

• This leaves the very beginning of LS1.


Fast power aborts in 600A circuits

06/12/2012

2nd proposal


Motivation

06/12/2012

By E. Ravaioli

The purpose of these FPA’s are to verify PSpice models

More events at different current levels are needed for verification


Motivation

06/12/2012

• PSpice is not a tool to be used for modelling circuits where the circuit behaviour can easily be calculated. For quench modelling other software like ROXIE is much better.

• The advantages of PSpice is when investigating:

• Current change in magnets during quench in non-trivial circuits.

• Effect of quench-back in circuits with multiple magnets.

• Effect of failures in other circuit components (Switch, Crowbar, PC etc.).

• Analysis of circuit behaviour during an unusual event.

Why have PSpice models?


Motivation

06/12/2012

Principal drawing of RQTD circuit.

Why have PSpice models?


Test description

06/12/2012

• FPA at two current levels above quench-back limit to give a well-distributed set of events is proposed.

• No quench-back in: RCD, RCS, ROD, ROF, RQ6, RQS (with 4 magnets) and RQS (Without EE).

• Only one circuit of each type is going to be tested.


Test description

06/12/2012

Circuit QPS Inom [A] Current @ FPA 1 [A]

Current @ FPA 2 [A]

1 RQ6 EE 550 350 4752 RQS EE 550 300 4503 RQS EE 550 450 5004 RQT no EE 550 450 5005 RQTD and RQTF EE 550 350 4756 RQTL7 no EE 550 425 5007 RQTL10 no EE 550 425 5008 RQTL11 no EE 550 425 5009 RQTL9 EE 550 350 475

10 RSD1 EE 550 450 50011 RSD2 EE 550 450 50012 RSF EE 550 450 50013 RSF EE 550 450 50014 RSS EE 550 350 47515 RCBXH no EE 550 450 50016 RCBXV no EE 550 450 50017 RQSX3 no EE 550 450 500

List of proposed tests

Note: all of based on the assumption that the circuits are going to be tested all nominal current during the powering tests in the beginning of LS1. Current levels will have to be revised in the case that restrictions on the maximum current levels are introduced.


Test description

06/12/2012

Resources

• The test involves 17 circuits with 2 fast power aborts per circuit.

• Can be executed in parallel with a recovery and ramp-up time of 15 min. ̴��

• Total test time of 2 hours.

• No special equipment needed.


Test description

06/12/2012

Safety

• No remarks since all tests fall within what can be characterised as ‘normal’ operation.


Test description

06/12/2012

When?

• The tests can be performed in any circuit of the defined type and do not have to be performed in the same sector.

• Circuits have to be cold, which means in the very beginning of LS1.

• Could be done during operation before LS1.

Daniel Egede Rasmussen TE-MPE-PE 2006/12/2012

Thank you for your attention

Special powering test proposals for LS1

Documents

Transcript of Special powering test proposals for LS1