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Copper Stabilizer Continuity Measurement Project

CSCM Mini ReviewPowering Implementation

H. Thiesen 30 November 2011

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CSCM powering implementation

Outline• Voltage and current requirements• Modification of RB power converter• RB circuit powering configuration• RQ circuit powering configuration• How to power RQ circuits with RB power converter?• Validation tests before CSCM of RB circuit• Validation tests before CSCM of RQD and RQF circuits• Preparation phase (summary)• Powering tests• Recovery phase• Conclusion

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Voltage and current requirements

t1 t2

500 A

4-6 kA

60 s

PC in voltage mode PC in current mode

Trip by mQPS th

T = 20 K

I

t

• The initial objective of the project was a possible increase of LHC energy at 5 TeV in 2012.

• CSCM consists to warm up the arc at 20 K and to generate current pulses (4-6 kA) inside the circuit.

• The magnets are not superconducting

• The current passes through the by pass diodes

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Voltage and current requirements

• Assumption (to be verified): 1.7 < Vdiode < 2 V at 20 K

• The magnets are not superconducting (30 mW/0.1H)

• The current passes through the by pass diodes

RB circuit

[6kA

/300

V]

Open circuit Short circuit

RQ circuits (in series)

[6kA

/250

V]

Open circuit Short circuit

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The actual power converter ratings are RB=[13kA/±190V] and RQ=[13kA/18V]=> New 2MW power converters

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• CSCM requires [6kA,300V] power converters (for 5 TeV)

• Connect in series both RB power converters (UAx3 and UAx7)

• [13kA,380V] can be reach with this solution

• 500 m between the power converters

• How to control the both converters (2 independent electronics)?

• Modify the RB power converter

• Normal configuration: 2 bridges in // to reach [13kA,190V]

• CSCM configuration: 2 bridges in series to reach [6.5kA,380V]

Þ Modification of actual RB power converter configuration:• Individual system tests (IST) before to power the circuits

Þ Same converter for the 3 main circuits (RB, RQD and RQF)• Hardware intervention between two measurements

Voltage and current requirementsH

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30

No

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201

1

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Modification of RB power converter

• RB power converter modification

(+)

(-)

6x240mm2

• Put in series the both thyristor bridges• Change Vout_meas• Put output diode to suppress voltage

oscillations (before DCCTs)

100 W

100 W

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Modification of RB power converter

• Results of P-Hall

Tests in P-Hall with 4 W load

U_bridge

U_out

U_out

I_out

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-1000

0

1000

2000

3000

4000

5000

6000

7000

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35

2*EE

0*EE

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RB circuit powering configuration

• RB powering configuration

• To reduce voltage constraint in case of switch opening (2 kV at 6 kA) which can damage the circuit or the diodes, it is important to short circuit the both EE systems (do not forget to remove the SC after the tests)

• In this configuration the diode voltages are enough to discharge quickly the energy stored in the circuit in case of runaway

RB 300 V300V

1x240mm2 1x240mm2Rearth(500V)

time (s)

current (A)

< 350 ms

Þ max. voltage to earth in case of fault is #400 V at 20K

0V150V

150V300V

Þ Minimal impact on EE system, IST (before and after CSCM) is not needed

Vdiode = 0.7 VL = 5 mHVout Pc = 0V

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From Standard ELQA procedure (Edms:788197)

From SM18 Test benches:

Proposed ELQA Test for CSCM

Pressure in the cold masses of the ARC: P > 5.5 bar (> 4.0 bar is acceptable)

Pressure in the DFBAs: P > 1.8 bar (same condition as TP4-C)

Circuit @ 300 K, p=1 bar @ 1.9 K p=1 bar

Main Dipole vs GND 600 V 600 V, 1900 V and 3100 V

Circuit TP4-C,T=80K, p=6 bar

TP4-E,T=1.9K, p=1 bar

Main Dipole vs GND 600 V 1900 V

Circuit Max Voltage expected

@20 K

ELQA HVQ,T=20 K, p> 5.5 bar (>

4.0 bar)

Max leakage current after 300s.

Main Dipole vs GND 400 V 600 V (standard value) 50 µA

From G. D’AngeloH. T

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RB circuit powering configuration

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RB circuit powering configuration

• Impact on the PIC (Power Interlock Controller – link between QPS and PC)

• PIC is an important element for the protection of the circuit during CSCM.

• PPermit (software INTK with mainly cryo and UPS conditions) is needed to run

• Global abort must be disabled

• CS (cryo start) and CM (cryo maintain) must be disabled

• UPS OK will be maintained during the CSCM to avoid hardware modification of this signal => UPSs (both points) must be operational

• Other impact

• Electrical distribution must be operational

• Water distribution must be operational

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RQ circuit powering configuration

• 2 possible configurations

• Individual CSCM configuration

• Series CSCM configuration

RQF

Þ Easier to realize

Þ More realistic for the by pass diodes

RQD

RQF

RB Earth system

RB Earth system

RB

RB

RQF EE system

RQF EE system

RQD EE system

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RQ circuit powering configuration

• Series configuration

• To reduce voltage constraints for the circuit at 20K (magnet to ground) we propose to short circuit one EE system

0

1000

2000

3000

4000

5000

6000

7000

0 0.2 0.4 0.6 0.8 1 1.2

2*EE

1*EE

0*EE

0.25

0.36

0.85

time (s)

current (A)Vdiode = 0.7 VL = 10 mHVout PC = 0 V

RQD

RQF

RB300V

0V

0V

-150V

150V

75V

-75V

0V

(-300V)

RB Earth system

RQF EE system

RQD EE system

Þ max. voltage to earth in case of fault is #300 V at 20K

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From Standard ELQA procedure (Edms:788197)

From SM18 Test benches:

Proposed ELQA Test for CSCM

Pressure in the cold masses of the ARC: P > 5.5 bar (> 4.0 bar is acceptable)

Pressure in the DFBAs: P > 1.8 bar (same condition as TP4-C)

Circuit @ 300 K, p=1 bar @ 1.9 K p=1 bar

Main Quad vs GND 180 V 180 V, 900 V

Circuit TP4-C,T=80K, p=6 bar

TP4-E,T=1.9K, p=1 bar

Main Quad vs GND 120 V 240 V

Circuit Max Voltage expected @20 K

ELQA HVQ,T=20 K, p> 5.5 bar

(> 4.0 bar)

Max leakage current after

300s.

Main Quad vs GND 200 V one by one, or 300 V both in series

360 V(max voltage*1.2)

20 µA

ELQA under this condition has not been done before, but it should not be a problem!

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RQ circuit powering configuration

From G. D’Angelo

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How to power RQ circuits with RB power converter?

• DC connection

• Link RQ circuits to RB power converter with 6x240mm2 DC cables at the power converter level (can be done during RB modifications)

6x240mm2 (1.25 mW)

RQF RQD RB

RB power converterRQD power converterRQF power converter

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How to power RQ circuits with RB power converter?

• Earth fault detection system

• Connect the RB earth fault detection system to the middle point of RQ discharge resistor (IST before and after CSCM of RQ circuits)

• Remote control

• Change the WorldFIP address by using “derivFIP” (IST before and after CSCM of RQ circuits)

• PIC

• Link the RQ PIC signals to RB power converter

Interface Box *

to RB power converterto RQD PIC

to RQF PIC

* not needed if individual powering

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• PIC interface box

• Signal exchanged between power converters and PIC

• Cable connected => use only RQD signal (RQF signal short circuited)

• PC failure => use only RQD signal (RQF signal short circuited)

• SwOpRq => use only RQD signal (RQF signal short circuited)

• PPermit => put the both signals in series

• FastPA => Put the both signals in series

How to power RQ circuits with RB power converter?

RB converter

PIC_RQD

PIC_RQF

Signal from power converter to PIC

Signal from PIC to power converter

• Other external interlocks

• water cooled DC cables (not used)

• Current lead thermal switches (not installed today)

RB converter

PIC_RQD

PIC_RQF

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Validation tests before CSCM of RB circuit

• Individual System Test (IST)

• CSCM needs important modification of powering circuits (RB, RQD and RQF) => Validation tests before CSCM

• The 1st step is to valid the “new-RB” power converter with external resistor

• Local tests

• Safety issues are limited

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Validation tests before CSCM of RB circuit

• PIC tests

• PIC tests are the second step of the powering validation

• Objective of these tests is to validate the circuit protection system

• PPermit

• FastPA

• PCfailure

• Condition for the PIC tests

• Ready to powering but new-RB power converter still connected to the 4W load (not connected to the circuits).

• PIC tests are done from the CCC

• Safety issues are limited

• Question: Do we need to repeat PIC tests with current?

After IST of PC (and IST of QPS) and PIC tests=>

Green light for CSCM

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Validation tests before CSCM of RQD and RQF circuits

• Individual System Test (IST)

• IST of new-RB power converter is needed except if it done before for CSCM of RB circuit

• Check of the address of new-RB power converter

• PIC tests

• new-RB power converter must be connected (or reconnected) to 4 W load. tests

• PIC tests are done from the CCC

• Interaction with Xmas stop is limited

• Safety issues are limited

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Preparation phase (summary)

• Different tasks

• Modification of RB power converter

• Installation of EE system short circuits (both RB and RQF)

• Installation of DC cables between RB power converter and RQD and RQF water colled DC cables (at the power converter level)

• PIC software straps (global abort, CS and CM)

• Installation of the PIC interface box

• Installation of the DerivFIP

• Modification of RQ Earth point (between RB CSCM and RQ CSCM)

• IST of new-RB power converter

• PIC tests for RB CSCM

• PIC tests for RQ CSCM (between RB CSCM and RQ CSCM).

• Time and Resources

• 2 weeks and 1 extra day between RB CSCM and RQ CSCM

• 1 Engineer + 2 power technicians + 2 electro-mechanics

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Powering tests

• Open issues

• Identification of the CSCM loads (magnets with diodes in parallel)

• Behavior of new-RB power converter with the CSCM loads

• Start up and current regulation of new-RB power converter with the CSCM loads

• Time and Resources

• 2 weeks (with the reconfiguration day between RB CSCM and RQ CSCM)

• 1 Engineer + 1 power technician

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Recovery phase

• Different tasks

• Reconfiguration of RB power converter

• Remove EE system short circuits (both RB and RQF)

• Remove DC cable between RB power converter and RQD and RQF water colled DC cable (at the power converter level)

• Remove PIC software straps (global abort, CS and CM)

• Remove the PIC interface box

• Remove the DerivFIP

• Change RQ Earth point (between RB CSCM and RQ CSCM)

• IST of RB power converter

• PIC tests for RB power converter

• PIC tests for RQ power converters

• Time and Resources

• 2 weeks and 1 extra day between RB CSCM and RQ CSCM

• 1 Engineer + 2 power technicians + 2 electro-mechanics

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Conclusion

• CSCM requests important modifications of main circuits (RB, RQD and RQF)

• Power converter, EE systems, PIC, QPS

• IST and PIC tests are needed before CSCM and between RB CSCM and RQ CSCM

• Still open issues mainly linked with the power converter control with the CSCM loads

• Full recommissioning (PIC1, PCC, PIC2, PLI1, etc…) of the main circuits after CSCM.

• CSCM tests can be done only by specialists and time is needed.

• Tests procedure must be written and approved

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