Transcript (R9) Launch the Copper Stabilizer Continuity

Second LHC Splice Review
Copper Stabilizer Continuity Measurement
possible QC tool for consolidated splices
K. Brodzinski, Z. Charifoulline, G. D’Angelo, M. Koratzinos, J. Steckert,
H. Thiesen, A. Verweij
H. Thiesen
28 November 2011
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CSCM possible QC tool for consolidation splices
Outline
H. Thiesen – 28 November 2011
•
•
•
•
•
•
•
•
Project motivations and objectives
Tests description
Powering implementation
Circuit protection
Cryogenic issues
Main risks
Planning and impact
Conclusion
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Project motivations and objectives
Conclusions of Steve Myers from Chamonix 2011:
Recommendations of the 3rd MAC meeting:
Recommendation:
H. Thiesen – 28 November 2011
(R9) Launch the Copper Stabilizer
Continuity Measurements Project aimed
at the measurement of all the copper
stabilizer joints in all the LHC sectors
during the technical stop at the end of
2011. On the basis of these
measurements the safe 2012 operation
beam energy can then be determined.
• The CSCM project was launched after Chamonix 2011 to identify for each main
circuits (MB and MQ) the maximum safe current.
• The main objective is a possible increase of energy in 2012.
3
Test description
•
•
CSCM tests consist to reproduce similar conditions to those during a quench, but
w/o energy stored in the magnets so that the thermal runaway can safely be
stopped by an interlock process.
This is achieved by doing the test at a temperature of about 20K, so that the
magnets are no longer superconducting and the current passes through the
bypass diodes connected to all main magnets.
I_circuit, V_bus
4-6 kA
T = 20 K
H. Thiesen – 28 November 2011
Trip by mQPS th
500 A
t
t1
PC in voltage mode
60 s
PC in current mode
t2
Test description
• During the test the busbar segment voltages are measured to detect the runaway.
• Maximum safe current of the circuit can be calculated with the time delay and the
current level.
Board A
350
6000
Current
300
5000
Tpeak
250
4000
200
3000
150
2000
100
1000
50
0
0
0
10
20
30
Time [s]
40
50
60
200
Vres
160
Voltage [mV]
time delay
Peak temperature [K]
Current [A]
H. Thiesen – 28 November 2011
7000
Vind
Vres+Vind
120
80
40
0
0
10
20
30
Time [s]
40
50
60
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Limitation of CSCM
• The CSCM does not measure the quality of each splice. It can only identify the
worst one.
Cool down
CSCM tests
yes
H. Thiesen – 28 November 2011
Warm up
Run
away
no
Warm-up and repair is only needed if the
current at which the machine will run is larger
than the safe current deduced from the CSCM
test.
repair
OK
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What can the CSCM measure?
• The CSCM can also measure:
• All 13 kA current lead-busbar connections at the DFB
H. Thiesen – 28 November 2011
• All bypass diode paths
Test implementation
• LHC has been designed to operate the main dipole and quadrupole magnets with
super fluid helium at 1.9K.
• CSCM requests to operate the main MB and MQ magnets with gaseous helium at
20 K.
• Special cryogenic control to maintain the arc at 20K
• Special powering configuration to inject 6kA in the circuits
• Special protection system to protect the circuits during the powering tests
H. Thiesen – 28 November 2011
• The new powering configuration and the circuit protection system have to be
designed and commissioned as permanent systems
Powering configuration
• The voltage delivered by RB (190V) and RQ (18V) power converters are not
enough for the CSCM tests:
• 1.7 < Vdiode < 2 V at 20 K (assumption)
H. Thiesen – 28 November 2011
Open circuit
Short circuit
RB circuit
Open circuit
Short circuit
RQ circuits (in series)
 Modification of actual RB power converter to obtain the requested voltage
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Powering configuration
• Modification of RB power converter
L
L
L
L
CSCM configuration
Normal configuration
U_out
H. Thiesen – 28 November 2011
U_out
I_out
U_bridge
Tests in P-Hall with 4 W load
Same modified power converter (RB) for the both circuits (MB and MQs)
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Powering configuration
• RB powering configuration
7000
Vdiode = 0.7 V
L = 5 mH
Vout Pc = 0V
current (A)
6000
5000
4000
RB
300V
300 V
2*EE
3000
0*EE
2000
1000
1x240mm2
1x240mm2
< 350 ms
time (s)
0
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
-1000
• RQ powering configuration
7000
Vdiode = 0.7 V
L = 10 mH
Vout PC = 0 V
current (A)
RQF
6000
5000
4000
RB
300V
2*EE
1*EE
3000
0*EE
0.85
0.25
H. Thiesen – 28 November 2011
1000
RQD
0.36
2000
0
time (s)
0
0.2
0.4
0.6
0.8
1
1.2
• Main challenge = How to control the current in the “diode circuits” ?
• 5 bars have to be maintained in the cryostat to have 400V insulation
voltage at 20K
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CSCM protection system
• During the powering tests, the CSCM protection system have to protect:
• Busbar segments
• Current lead
• Magnets
BB splice & diode BB -> mDQQBS board
Ures
…
H. Thiesen – 28 November 2011
PC
EE system bridged
…
Current Leads
Existing DQQDC detector
(3mV 100ms)
PIC
Interlock Loop from QPS
Umag
Global BB detector
(monitoring)
EE system is
bridged
Current Leads
Existing DQQDC detector
(3mV 100ms)
Diode/Magnet
DQQDS measures voltage over 4 magnets
if difference is > threshold, current will be cut
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CSCM protection system
• Busbar protection system
absolute threshold
H. Thiesen – 28 November 2011
ramp
Usplice
1000 boards are in production and will be
delivered in December 2011
plateau
dv/dt threshold
dv/dt
splice
Recorded mDQQBS buffer, stimulated with simulated signal for a bad splice
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CSCM protection system
Connectio
n
Connectio
n
• Tests in SM18
VT1
The busbar segment protection system has been tested in SM18
• 10 m of MQ busbar
• 50 mm single-sided defect
VT13
VT1-13
L=11.4m
mBS, board A
VT5
mBS
T1
I2C/SPI
VT4
IMAX=5.1kA
dI/dt = 200A/s
T = 14.5K
VT12
VT6
T2
VT7
H. Thiesen – 28 November 2011
VT3
VT8
T3
VT9
mBS, board B
UBUS
T6
T4
VT2
VT10
VT11
dV/dt
T5
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Special cryogenic condition
• Requested cryogenic conditions can be provided with good stability and
homogeneity over a sector length: ARC at 20 K and 5 bars, DFBs cooled with 20 K
GHe to maintain the current lead at nominal condition (TT891A@50K)
• Proposed cooling of DFBs have to be analyzed in more in details
• Particularity of busbar interface between DFB/Q7 interface to be studied
• Recovery after each powering test is estimated at 5 hours
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Homogeneity over a sector length for RRR
C11L4_11L4_TTAVG.POSST
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C13L4_13L4_TTAVG.POSST
C1513_15L4_TTAVG.POSST
conditioning
RRR tests
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C15L4_15L4_TTAVG.POSST
C17L4_17L4_TTAVG.POSST
stabilization
C1917_19L4_TTAVG.POSST
C19L4_19L4_TTAVG.POSST
C21L4_21L4_TTAVG.POSST
10
C2321_23L4_TTAVG.POSST
C23L4_23L4_TTAVG.POSST
C25L4_25L4_TTAVG.POSST
5
C2725_27L4_TTAVG.POSST
C27L4_27L4_TTAVG.POSST
C29L4_29L4_TTAVG.POSST
0
2010/12/11 00:00
2010/12/11 03:32
2010/12/11 07:04
2010/12/11 10:36
2010/12/11 14:08
2010/12/11 17:40
2010/12/11 21:12
2010/12/12 00:44
2010/12/12 04:16
2010/12/12 07:48
2010/12/12 11:20
2010/12/12 14:52
2010/12/12 18:24
2010/12/12 21:56
2010/12/13 01:28
2010/12/13 05:00
2010/12/13 08:32
2010/12/13 12:04
2010/12/13 15:36
2010/12/13 19:08
2010/12/13 22:40
2010/12/14 02:12
2010/12/14 05:44
2010/12/14 09:16
2010/12/14 12:48
2010/12/14 16:20
2010/12/14 19:52
2010/12/14 23:24
2010/12/15 02:56
2010/12/15 06:28
2010/12/15 10:00
2010/12/15 13:32
2010/12/15 17:04
2010/12/15 20:36
Temperature [K]
C1109_11L4_TTAVG.POSST
C3129_31L4_TTAVG.POSST
C31L4_31L4_TTAVG.POSST
C33L4_33L4_TTAVG.POSST
CSCM main risks
• CSCM tests
• During the CSCM tests the main risks (extremely small) are to damage a
splice, a diode, a magnet or a DFBA (current leads or splice).
• Splice or diode are “easy” to repair (warm up, repair, cool down, CSCM tests)
• Magnet is “easy” to replace if spare is available (warm up, replace, etc…).
• DFBA is more complex to repair: must be transport to the surface.
• Recovery
• Important modification have to be done to realize the CSCM tests
H. Thiesen – 28 November 2011
• The main risk is to do a mistake during the recovery
• The risk can be mitigate to acceptable level by procedure for reconfiguration,
test and (re)commissioning.
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CSCM planning
• CSCM tests request time and resources
s1 s2
Brief estimation of time
• 2 sectors in parallel
• 2 weeks for preparation
• 2 weeks for the tests
• 2 weeks for the recovery and recommissioning
s3 s4
18 weeks (4.5 months) to tests the LHC
H. Thiesen – 28 November 2011
s5 s6
s7 s8
- Planning can be optimized to reduce the time at 3.5 or
2.5 months
- Preparation time can be done in parallel with the other
LS1 activities
- But powering tests can be done only during the night
- CSCM campaign requests resources: 8 to 10 tech. or
Eng.
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CSCM planning
• If CSCM tests must be realized after the consolidation of the splices:
• The project have to be approved in March - April 2012
• Type test has to be realized in one sector at the beginning of the LS1 (6
weeks)
H. Thiesen – 28 November 2011
• CSCM campaign has to be integrated in the LS1
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Conclusion
• CSCM tests can be used to qualify the LHC at 7 TeV after the splice consolidation:
qualification of the splices, diode paths and current lead – busbar connections
• CSCM tests require to modify several critical systems as QPS, 13kA-EE, PIC and
PC: full re-commissioning (IST and powering tests) is mandatory.
• Cryogenic conditions can be provided with good stability and homogeneity over a
sector length but proposed cooling of the DFBs has to be analyzed in details.
• CSCM tests will interfere with other LS1 activities
• CSCM tests present some risks (extremely small): damage a splice or a DFB/CL
can not be excluded
H. Thiesen – 28 November 2011
• CSCM tests require time (2.5-3.5 months) and resources (8-10 techniciansEngineers)
• Engineering challenges are being met and a test and simulation program is under
way (validation of protection system, correlation between 20 K and 1.9 K, control
of power converter)
• No show stoppers found so far but there are some open issue as PC current
control.
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