Trim Test in SM18
S. Yammine in collaboration with H. Thiesen
TE-EPC-MPC
08/04/2016
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Contents
01
02
03
04
Introduction
Failure Scenarios and Critical Tests
Test Configurations
Proposition
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3rd International Review of the 11 T Dipoles at Collimator Section for the HL-LHC - Trim Test in SM18 08/04/2016
2
01
Introduction
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3rd International Review of the 11 T Dipoles at Collimator Section for the HL-LHC - Trim Test in SM18 08/04/2016
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Introduction


11 T dipole is series with the main dipoles
Trim circuit is in parallel with the 11T
TRIM PC LS3
C8
C11
C10
TRIM PC LS2
C9
C8
Type A Dipole
Type B Dipole
RB.A67
102 mH
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132 mH
132 mH
11T Dipole
3rd International Review of the 11 T Dipoles at Collimator Section for the HL-LHC - Trim Test in SM18 08/04/2016
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02
Most Critical Failure Scenarios
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3rd International Review of the 11 T Dipoles at Collimator Section for the HL-LHC - Trim Test in SM18 08/04/2016
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Failure Scenarios

Trim PC Failure – Failure 1



Actions : Trim Crowbar + RB Crowbar + Stop PCs
Worst Case Scenario : IMains = 6 kA - ITrim = -250
Remark : The dipole is a current source (current inertia)
Trim PC
RCrow
RCrow
RCable/2
L11T
RCable/2
N.LMB
ITRIM
ITRIM
N.LMB
RCable/2
I11T
I11T
V11T
V11T
RCrow
Rtotal < 20 mΩ →
Diode not triggered
VDiode = Rtotal Itrim
Rtotal > 20 mΩ →
Diode triggered
RCrow
RExtraction
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L11T
RCable/2
Diode triggered : what is impact on
the system (diode voltage,
cryogenics, quench) ?
3rd International Review of the 11 T Dipoles at Collimator Section for the HL-LHC - Trim Test in SM18 08/04/2016
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Failure Scenarios

FPA – Failure 2



Actions : Trim Crowbar + RB Crowbar + Stop PCs + EESs
Worst Case Scenario : IMains = 12.85 kA - ITrim = 34 A
Remark : V11T = 12 V
Trim PC
RCrow
RCrow
RCable/2
N.LMB
L11T
L11T
Itrim = V11T /Rtotal
I11T
I11T
V11T
V11T
Rtotal < 60 mΩ →
Overcurrent
RCrow
RCrow
RExtraction
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RCable/2
Rtotal > 60 mΩ →
No overcurrent
ITRIM
ITRIM
N.LMB
RCable/2
RCable/2
RExtraction
Overcurrent : 800-1000 A for a
circuit sized for 300 A
3rd International Review of the 11 T Dipoles at Collimator Section for the HL-LHC - Trim Test in SM18 08/04/2016
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03
Test Configurations
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3rd International Review of the 11 T Dipoles at Collimator Section for the HL-LHC - Trim Test in SM18 08/04/2016
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Test Configurations

Proposition of Test Configurations
Water Cooled
Warm Cables
Trim PC
Cluster 2
Cluster 1
Trim PC
MB11T
MB
Configuration 1 Control of the 2 PCs
together highly
complex
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MB11T
Configuration 2 (On
Two Clusters)
3rd International Review of the 11 T Dipoles at Collimator Section for the HL-LHC - Trim Test in SM18 08/04/2016
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Test Configurations

Configuration 1 Simulation
εI
Control
Trim PC
α
α
L11T
ITrim_Ref
IMeas
I_RB
Control
εI
IMains_Ref
IMeas
I_RB_REF
I_RB
I_RB_REF
15K
12.00684K
MB11T
10K
12.001 95K
Unstable Control : Result of
connecting two voltage sources
5K
11.99707K
0K
11.99219K
-5K
I_TRIM_1
I_TRIM_REF_1
11.9873K
50
0
11.982 42K
-50
I_TRIM_1
I_TRIM_REF_1
20
-100
-150
Impossible to control 2 currents
using this configuration
-200
10
-250
-300
0
alpha_TRIM
0.6
0.4
-10
0.2
0
-0.2
-20
1.2999512
-0.4
1.2999634
1.2999756
Time (Ks)
-0.6
-0.8
0
200
400
600
800
Time (s)
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1000
120 0
1400
Instability
3rd International Review of the 11 T Dipoles at Collimator Section for the HL-LHC - Trim Test in SM18 08/04/2016
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Test Configurations

Configuration 1 Simulation
Trim PC

Proposed solutions : Voltage control on one PC + Current Control on the other.
I_RB
MB11T
I_RB_REF
12K
10K
8K
6K
4K
2K
0K
-2K
I_TRIM_1
Current control is still unstable! It will be
worse on the test bench.
I_TRIM_REF_1
50
0
-50
-100
-150
-200
-250
-300
alpha
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
V_RB_1
Instability
1.08
1.04
1
0.96
0.92
0
200
400
600
800
1000
1200
1400
Time (s)
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3rd International Review of the 11 T Dipoles at Collimator Section for the HL-LHC - Trim Test in SM18 08/04/2016
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Test Configurations

Configuration 2 Simulation
Trim PC


No problems for configuration 2
Questions to answer : What is the complexity to implement this solution via warm
cables in SM18?
I_RB
I_RB_REF
12K
10K
8K
MB
MB11T
6K
4K
2K
0K
I_TRIM_1
I_TRIM_REF_1
50
0
-50
Configuration 2 (On
Two Clusters) Control of the 2 PCs
together possible
-100
-150
-200
-250
-300
alpha
0.4
0.2
0
-0.2
-0.4
200
400
600
800
1000
1200
Time (s)
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3rd International Review of the 11 T Dipoles at Collimator Section for the HL-LHC - Trim Test in SM18 08/04/2016
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Test Configurations

Testing Possibilities
Trim PC
Tests
Configuration 1
Configuration 2
Water Cooled
Warm Cables
Trim Operation Verification
(without second PC)
Yes
Yes
11T TF
Yes
Yes
Trim Overcurrent Test
No
Yes
Partial Bypass Diode Constraint
Yes
Yes
Complete Bypass Diode Constraint
No
Yes
2 PCs Test
No
Yes
Cluster 2
Cluster 1
MB11T
MB
Configuration 1
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Trim PC
MB11T
Configuration 2
3rd International Review of the 11 T Dipoles at Collimator Section for the HL-LHC - Trim Test in SM18 08/04/2016
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04
Proposition
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3rd International Review of the 11 T Dipoles at Collimator Section for the HL-LHC - Trim Test in SM18 08/04/2016
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Proposition

Test Plan Study (April - September) :




Test configuration alternatives
Feasibility study
Instrumentation required
Test plan definition
Water Cooled
Warm Cables
Cluster 2
Cluster 1
MB
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Trim PC
MB11T
3rd International Review of the 11 T Dipoles at Collimator Section for the HL-LHC - Trim Test in SM18 08/04/2016
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Thank you for your attention
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3rd International Review of the 11 T Dipoles at Collimator Section for the HL-LHC - Trim Test in SM18 08/04/2016
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Test Configurations
Alternative Proposed Solutions :
 Dummy Load : We need a high inductance (6kA). Possible ?


We discussed putting a dummy load on the trim side : Alteration of the circuit property – The
test will not be viable anymore.
Putting a dummy load on the mains side is a possibility but we need a 6 kA inductance!

Voltage control + Current control : Control not possible.

Any other propositions are welcome
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3rd International Review of the 11 T Dipoles at Collimator Section for the HL-LHC - Trim Test in SM18 08/04/2016
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