Transcript ABSTRACT - At the end of 2012, the Large Hadron Collider will enter its first programmed long stop (LS1). The problem.

ABSTRACT - At the end of 2012, the Large Hadron Collider will enter its first programmed long stop (LS1).
The problem at the origin of 2008 incident will be definitely treated and the main circuits will then be able
to run at the design current value without protection issues. At Chamonix 2011, a proposal was done for a
series of powering tests to be performed just before the LS1 to investigate other potential limitations in
the machine, which could be fixed during the same maintenance period. A review of these powering tests
is presented, together with the list of investigation to be performed by the electrical quality assurance
(ElQA) team. A tentative planning is as well proposed. Moreover, following complementary activities
during the LS1, a huge campaign of individual system tests will have to be as well performed during the
shutdown. Attention will be put on the preliminary list of needed re-qualifications.
MIRKO POJER
POWERING TESTS BEFORE LHC WARM-UP:
WHAT IS NEW FROM CHAMONIX 2011?
Acknowledgements: R. Schmidt, A. Siemko, G. D’Angelo,
S. Fartoukh, E. Metral, M. Giovannozzi, A. Ballarino,
R. Denz, K. Dahlerup-Petersen, H. Thiesen
PREAMBLE
At present, 2 weeks have been
allocated for “special” powering
tests, to detect possible
limitations other than the
splices for the design operation
of the superconducting circuits
(after LS1 there should be no
known constrain to the 7 TeV
target)
Ongoing discussion…
2/8/2012
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
2
OUTLINE
• Powering tests to be performed before LS1
–
–
–
Recap of what presented in Chamonix 2011
What to push to nominal … and further
Other tests (QPS-”triggered”, etc)
• CSCM
–
–
CSCM as current bypass quality control: do we want to perform a type test at
the end of the year?
Technicalities
• ElQA tests
–
–
New HV parameters
Special tests
• LS1 and after
–
2/8/2012
Individual system test, short-circuit campaign and re-commissioning
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
3
STATUS OF COMMISSIONING IN 2008
(WHEN WE WERE AIMING AT THE DESIGN PERFORMANCE)
• Excluding the main circuits (RBs, RQD/Fs) and not considering sector 34,
at the end of 2008, all circuits were commissioned to 7 TeV equi. current, except:
– RQX.L5 was commissioned to less than 5 TeV, due to change in nominal current
– IPDs
• I_nom was changed for RD3.R4 and RD4.R4 after commissioning, which then resulted in less
than 7 TeV (6.6 and 6.3 TeV, respectively)
• RD2.R8 quenched 4 times (5816, 5788, 5856 and 5854 A) at less than 6.8 TeV
– 600 A were “jeopardized”, due to the reduction of target current/energy and to the
change of specifications
• 142 over 410 circuits were commissioned up to 5 TeV or even below
– Some 80-120 A were not commissioned for 7 TeV
•
•
•
•
RCBYV5.L4B2 suffered three quenches without training (limited to 50 A)
RCBYHS4.L5B1 had a hardware problem and was limited to half the energy (limited to 50 A)
RCBYHS5.R8B1 had a ramp-down quench after attaining the nominal (limited to 20 A)
RCBYH4.R8B1 had a ramp-down quench after attaining the nominal (limited to 50 A)
– (IPQs all fine for 7 TeV)
2/8/2012
Commission up to 7 TeV all circuits, in particular:
RD3.R4, RD4.R4, RD2.R8 and RQX.L5
plus all missing 600 A circuits
plus all circuits in sector 34
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
4
WHAT TO PUSH HIGHER: THE LANDAU OCTUPOLES
•
•
In Evian ‘11, the request came to commission
the Landau octupoles to their nominal current in
2012; in fact, last year they were used in
operation at 400 A and more could be needed, if
we don’t manage to go to low chromaticity, to
control beam instabilities.
For higher energies:
–
–
•
550 A could be sufficient at 7 TeV, but tests will
be performed in MD this year (E. Metral)
S. Fartoukh estimates that we might need 600A,
if not more…
Feasibility and issues to go to 550 A
• In 2011 they had been commissioned to 400 A
• In 2008, the ROD/Fs were commissioned to 550 A in all sectors but S34, S45 (PNO.b1
missing) and S56
• Among the circuits tested to 550 A in 2008, very few quenches were observed:
–
–
–
2/8/2012
ROD.A78B2 had a training quench at 550 A (21/05/08; 17:00)
ROF.A78B2 had a training quench at 460 A (19/05/08; 8:21)
ROF.A81B1 had a training quench at 436 A (20/06/08; 14:00)
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
Commission to 600 A
5
WHAT TO PUSH HIGHER: THE LATTICE SEXTUPOLES
•
•
•
Concerning the other circuits, S. Fartoukh “would already test the lattice sextupoles up
to 600 A, or even discuss/test higher current. Actually this request stands only for the SD
circuits in s81,12,45,56 (so 16 out of 64 circuits).”
In 2008, they were commissioned to 550 A in S45 and in S81; elsewhere, they were
commissioned to 400 A.
Is the acceleration an issue?
•
"Biensur la longeur des segments risque de devenir de plus en plus grand a petit beta*
(ne serait-ce que pour le controle des RQ6 en IR1 et IR5 qui finissent a 210 A pour
beta*=60 cm!), mais ceci te montre qu'un gain d'un facteur 2 dans d2I/dt2 des RSs serait
bienvenu deja cette annee, et sera sans doute indispensable a 6.5 TeV et beta*=45 cm.
Puis si ATS en plus a 40cm et 6.5TeV, alors disons 1A/s2 serait formidable, sinon un
squeeze infiniment long ou pendant lequel on ne peux plus redemarrer si on s'arrete a
Commission to 600 A –
un certain beta* "(S. Fartoukh)
QPS issue: with the present acceleration, we are at the limit of the detection
threshold
improve
acceleration
After LS1, a new generation of detectors will be available, which are lessreducing
sensitiveI_nom
to inductance
in 2012?
2/8/2012
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
6
•
From the magnets point of view, could be
feasible (at least for the MO)
•
But there are some technical limitations to
consider:
–
The power converters are limited to 600 A
(RPMBB Designation PC:[600A 10V 4Q]
CRWB:600A DCCT:600A Mode:DC Type:B
without DC contactor)
•
Current at Quench [A]
CAN WE TEST THE MO OR MS TO MORE THAN 600 A?
Training Quenches at 1.8K on MOMM0003
1000
900
800
700
600
500
400
300
200
100
0
Training @1.8K on MOMM0003 Run 1
Training @ 1.8K on MOMM0003 Run 2
0
1
2
3
4
5
6
7
8
Quench Number
9
10
11
Not easy, from regulation point of view, to put
two in parallel
–
The current leads are dimensioned for 600 A max
and have been validated for this value. Larger
current values would require further testing at a
different temperature regulation (overcooling)
–
For the QPS “in principal there are no constraints
up to 600 A. The QPS current sensors are limited in
range to ±600 A and there is a programmed
interlock at ±610 A, meaning that you cannot
exceed this current.” [R. Denz]
Courtesy of A. Ballarino
2/8/2012
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
7
SURPRISES MIGHT APPEAR WHILE COMMISSIONING TO NOMINAL
•
Re-training in 2010 (2-quenches rule introduced to shorten commissioning)
600 A
80-120 A
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
RCD.A45B1 - NC 1035252 - quenched twice (at 300 and 391 A); limited toUsed
400 Ain
DIDT_P
2012A ACC_PN
RCD.A56B2 - NC 1026728 - quenched twice (at 479 and 496I_PNO
A); limited
I_PNOto 450
NO
O
I_PNO
(5TeV) (7 TeV)operation
(5TeV) (5TeV) (2010)
NAME
[A] limited
[A] to 450
[A/s]A [A/s ]
[A]
RCD.A81B1 - NC 1043522 - quenched twice (atCIRCUIT
351 and
484 A);
125
RQ6.L3B1
400
400
1.5
0.03
400
113
RQ6.L3B2
1.5
0.03
400
RQTL11.L2B2 - NC 1020622 - quenched (544.85
A); limited to400
500 A400
151
RQ6.L7B1* #
400
400
1.5
0.03
400
RQTL11.R5B1 - NC 1027448 - quenched twiceRQ6.L7B2*
(at 501 and 492
to139
450 A0.03
400A); limited
400
1.5
400
114
RQ6.R3B1
400
400
1.5
0.03
400
RQTL11.R5B2 - NC 1027413 - quenched twiceRQ6.R3B2
(at 550 and 533
to127
450 A0.03
400A); limited
400
1.5
400
132
RQ6.R7B1
400
400
1.5
0.03
400
RQTL11.L6B1 - NC 1026809 - long training (353,
292, 340, 350,
152
RQ6.R7B2
400384 A);
400 limited
1.5 to 300
0.03A 400
169
RQTL10.L7B1*
400
500
1.5
0.1
RQTL11.L6B2 - NC 1026747 - long training (267,
348, 384, 354,
382 A);
limited
A 400
27 to 300
RQTL10.L7B2*
400
500
1.5
0.1
400
-124
RQTL11.L3B1*
400
400
1.5
0.1
400
RQTL8.L7B1 - NC 1046464 - quenched twice RQTL11.L3B2*
(at 240 and 257 A); limited to 200
A
-163
400
400
1.5
0.1
400
18
RQTL11.L4B1
300
300
1.5
0.1
300
RQTL9.R3B2 - NC 1046992 - quenched at 359, 399.9 and 396.1 A; limited to-34
400 A
RQTL11.L4B2
300
300
1.5
0.1
300
43
RQTL11.L6B1*
400
400
1.5
0.1
RQT13.L5B1 - NC 1060679 - this magnet shows a strange behavior; I_PNO reduced to 400300
A
RQTL11.L6B2*
-48
400
400
1.5
0.1
300
-79
RQTL11.L7B1*
300 A); 300
300
RCBCV5.R5B2 - NC 1029792 - quenched twice
(at 69.4 and 76.9
limited 1.5
to 72A 0.1
5
RQTL11.L7B2*
300
300
1.5
0.1
300
RCBCH7.R3B1 - NC 1046994 - quenched twice
(at 98 and 95300
A); limited
80
RQTL11.R3B1
300 to -193
1.5 A
0.1
300
-113
RQTL11.R3B2
300
300
1.5
0.1
300
RCBYH4.R8B1 - NC 1051795 - quenched at 55.6
A; limited to300
50 A 300
RQTL11.R6B1*
1.5
0.1
300
-56
RQTL11.R6B2*
300
300
1.5
0.1
300
46
RCBYV5.L4B2 - NC 1049055 – 3 quenches w.o.
training (63.3,450
65.7 and
A); limited
50 A
RQTL8.L3B1*
450 64.71.5
0.1 to 450
17
RQTL8.L3B2*
450
450
1.5
0.1
450
-128
RCSSX3.L1 - NC 1053719 - the circuit trips when
it reaches 62.9
A; this
has been
RQTL8.L7B1*@
300
300
1.5
0.1
200
-89
2
DIDT_P ACC_PN
NO
O
(2010) (2010)
[A/s]
[A/s2]
1.5
0.03
1.5
0.03
1.2
0.03
1.5
0.03
1
0.06
1
0.06
1.5
0.1
1.5
0.1
1.5
0.1
1.5
0.1
1.5
0.1
1.5
0.1
5
0.1
5
0.1
1.5
0.1
1.5
0.1
1.5
0.1
1.5
0.1
1
0.1
1
0.1
1.5
0.1
1.5
0.1
1.5
0.1
1.5
0.1
1.5
0.1
300
1.5
0.1
300
1.5
0.1
proven 4RQTL8.L7B2*
times (circuit is300
now locked)
-23
RQTL8.R3B1
300
300
1.5
0.1
300
1
0.1
-117
circuit quenches
when coming
down300
from +-nominal
RQTL8.R3B2
300
1.5
0.1current
300 to zero;
1 the0.1
-15
RQTL9.L7B1*
400
400
1.5
0.1
400
1.5
0.1
-6
of the current also
shows high instability
(see EDMS
1053978)
RQTL9.L7B2*
400
400
1.5
0.1
400
1.5
0.1
186
400 magnet
500
1.5
0.1 2008
400 (see1.5
circuit can notRQTL9.R7B2**
handle di/dt : weak
known
since
MP3 0.15
134
RTQL9.R7B1**
400
500
1.5
0.1
400
1.5
0.15
39
• RCBYHS5.R8B1 - NC 1063839 control
• RCBYHS4.L5B1 - NC 1053709 -
meeting 4/11); tested with reduced I_PNO up to 60 A and OK so new I_PNO defined at 50 A
Not powered to 7 TeV in 2008
2/8/2012
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
8
WHAT TO DO IN CASE OF TRAINING?
•
How many quenches should we accept on the RD circuits?
– 4 or 5 quenches should be the minimum…
– Can we accept more?
•
How many quenches should we accept on the 600A and 120A circuits?
– Should we go up to 10 quenches?
– Should we stop earlier:
• accept a limitation in the machine?
• check for a different optics?
•
Review operational currents according to real
operation needs
All this will have to be addressed during the
year together with the nMP3 colleagues and a
proposal should be made to LMC
Detailed procedures shall be prepared before
the start of the powering tests
2/8/2012
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
9
STRATEGY FOR THE POWERING TESTS
• Full support by experts (QPS, EPC) during the testing phase
• nMP3 should quickly analyze critical cases
• To reduce the impact on other activities (see later, ElQA), powering
tests will have to be performed during evening/night for the high
current circuits; 600 A and below are in phase I
• Documentation:
– Powering procedures will be written this year on the tests to perform and
the way to execute them
– Status report will be written after the campaign, including
• Powering history
• Electrical NC
• ElQA test results: transfer function, etc…
2/8/2012
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
10
WHAT ELSE DO WE NEED TO TEST?
•
QPS
– Test of the RQTD/Fs with different logic for the tune FB (test of new boards)
– Test of the RCBXH3.L5
• Not clear where the fault is
• This circuit will be certainly needed at high energy
– Test of the undulator? (a series of tests is foreseen for the spare in SM18)
•
Do we want to fire all quench heaters to full voltage to check if there are critical
cases in the machine? (a monitoring tool will be in place only during TS1, that
compares the discharge with a reference [K. Dahlerup-Petersen])
2/8/2012
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
11
• Powering tests to be performed before LS1
–
–
–
Recap of what presented in Chamonix 2011
What to push to nominal … and further
Other tests (QPS-”triggered”, etc)
• CSCM
–
–
CSCM as current bypass quality control: do we want to perform a type test at
the end of the year?
Technicalities
• ElQA tests
–
–
New HV parameters
Special tests
• LS1 and after
–
2/8/2012
Individual system test, short-circuit campaign and re-commissioning
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
12
RISKS ASSOCIATED WITH A QUENCH
•
•
•
•
•
•
In normal conditions, the current is circulating through the splice,
into the magnet and back from the busbar through the other splice
When a quench occurs, the voltage drop inside the magnet is
increasing, the diode starts conducting and the current starts
flowing inside the bypass line
The diode is resistive and starts to heat up
The heat could propagate through the cable up to the splice and
eventually quench it--> serious damages if not conform!
Quench tests were performed to address this issue
(proposal Chamonix 2011, F. Bordry)
Collateral discovery: the resistance during discharge via
the bypass is much higher than expected
In the machine we have 2000
of these bypasses that have
never been tested
More details in Andrzej’s
presentation in Session 4
A16R5 anode: 2 consecutive quenches at 5 kA
2/8/2012
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
13
COPPER STABILIZER CONTINUITY MEASUREMENT (THERMAL AMPLIFIER)
•
•
Technique proposed by H. Pfeffer and later developed by H. Thiesen et al. to
investigate thermal runaway of faulty splices of an entire line
The method could be used to test all bypass current in the same line
1.Magnets at 20 K
2.Ramp to 500A with 20V/s to open all diodes
3.Check if diodes are open
4.Ramp up to plateau current with 300A/s
5.Plateau current (up to a maximum of 60s)
6.Discharge if U>Uthreshold
7.Ramp down to 0 A with 300A/s if U<Uthreshold
All technical problems addressed.
No showstopper identified.
2/8/2012
Another review in foreseen after summer
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
14
CSCM: TYPE TEST TIME ALLOCATION
2/8/2012
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
15
• Powering tests to be performed before LS1
–
–
–
Recap of what presented in Chamonix 2011
What to push to nominal … and further
Other tests (QPS-”triggered”, etc)
• CSCM
–
–
CSCM as current bypass quality control: do we want to perform a type test at
the end of the year?
Technicalities
• ElQA tests
–
–
New HV parameters
Special tests
• LS1 and after
–
2/8/2012
Individual system test, short-circuit campaign and re-commissioning
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
16
ELQA
•
2.2 HVQ - HIGH VOLTAGE QUALIFICATION
–
•
•
•
Each circuit is energized individually with respect to
ground using a DC voltage source limited to a
current of 2 mA and applying a test voltage as
defined in the annex B. During the test of a given
circuit, all other circuits of the same electrical safety
subsector are grounded for safety reason.
Reference documentation
Dipole lines (go and return) are tested separately,
since the circuit can be interrupted at the level the
warm cable connection
Tests of the two bus-bars of RQ together,
the bus cannot be interrupted
In the future, maximum operational voltage
against any neighbouring circuit will be taken
into account
–
–
–
2/8/2012
Which electrical circuits have bus-bars running
in the vicinity?
Consider nested circuits
Maximum operation voltage x1.2
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
17
ELQA
Tested
MB
MQ
MCS
MCD
MCO
MS
MSS
MO
MQS
MQSx
MQ6
MQTL(9)
MQTD/F
IPQ (1.9K)
IPD
MCB
Undulator
2/8/2012
1900
240
480
480
480(200)
600
600
600
360
360
360
360
360
480
600
600 (200)
500
Max op. voltage
3.5 TeV
7 TeV
450
487.5
376.5
520.1
376.5
840
339.5
840
199.5
420
399
840
301
840
406
840
399
840
399
840
399
840
399
840
406
840
266
420
600
600
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
Proposed voltage level
1900
650
1000
1000
480 (200)
1000
1000
1000
1000
1000
1000
1000
1000
480
600
600 (200)
500
18
ELQA
•
Another important activity of the ElQA team will consist in filling a reference
map to be used during and after LS1:
– MIC – measurement of the quench heater resistance
quench heater insulation (vs coil and ground)
– TFM – to be performed at cold and repeated at warm
•
Also a series of investigations will be performed on ill circuits, mainly to
diagnose shorts (RCOs, 120 A circuits,…)
•
Internal Splice Resistance Measurements will be performed in Feb-Mar (and
later during the technical stops) on the Inner Triplets; if not completed, they will
be carried out at the end of the year as part of the powering tests
•
We could re-measure the resistance of internal splices for critical magnets, to
confirm the need for replacement (might be possible during technical stops)
2/8/2012
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
19
CONCLUSIONS
•
Powering tests
– Commission to nominal current all circuits (RB and RQD/F excluded)
– Commission to ultimate the ROD/Fs and the RSD/Fs
– What about higher currents for the circuits above ? If needed, some measures must
be already taken – feasibility study
•
CSCM
– Time and resources for a type test have been considered
– Could we envisage to test more than a sector?
•
ElQA
– Qualification of all superconducting circuits to revised voltage levels
– Reference map before LS1
– Special investigations
A lot of material for discussion with nMP3 and LMC
Time estimate
• 3-4 days per sector for the powering tests (could do more sectors in parallel)
• 3 days with 2 teams per sector for the MIC
• 2days with 2 teams per sector for the HVQ
• ‘few’ additional days for special investigations by ElQA
2/8/2012
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
20
• Powering tests to be performed before LS1
–
–
–
Recap of what presented in Chamonix 2011
What to push to nominal … and further
Other tests (QPS-”triggered”, etc)
• CSCM
–
–
CSCM as current bypass quality control: do we want to perform a type test at
the end of the year?
Technicalities
• ElQA tests
–
–
New HV parameters
Special tests
• LS1 and after
–
2/8/2012
Individual system test, short-circuit campaign and re-commissioning
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
21
THE LS1 WILL BE THE OCCASION FOR MORE THAN SPLICE CONSOLIDATION
• Many system upgrade and maintenance activities will be performed
during the LS1
– QPS upgrades:
• additional systems for the diagnostics of the quench heater circuits (measure of
the resistance of the heater circuit with high precision - ΔR = 100 µΩ- in order to
see precursors of eventual faults [R. Denz]
• Specific transducers for precision measurement of the power pulse during
heater discharge of each of the 6076 heater circuits in the LHC [K. DahlerupPetersen]
• All other QPS instrumentation cables need to be checked after LS1 for electrical
insulation strength and correct wiring
• Detectors change and firmware upgrade
– Power converter modifications (active filters, auxiliary power supplies,…)
– Following R2E relocations, many electronic equipment will be removed
from areas close to the tunnel and put far away (see A.L. Perrot in this
same session)
– Cable re-routing (mainly at point 5, due to R2E) and change of cable
sheaths
2/8/2012
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
22
THE IMPACT ON RE-COMMISSIONING
•
All the above interventions will demand (before commissioning with powering test) for a
massive campaign of individual system tests, to check for
F L IR Sy s te m s
–
–
–
•
•
•
systems reliability
protection functionalities
effective QPS-PIC-PC interface
81.6 °C
80
Sp1
The cable activity will in particular require for
short-circuit tests and heat runs to be performed
New powering procedures will be needed
(not only for the training of the 13 kA circuits)
60
40
30.9
And later, we will have a brand new commissioning
More than 6 months of powering tests where the manpower could
become an issue (OP will be involved in splice consolidation).
Should we resume the figure of the Point Owners?
2/8/2012
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
23
Thanks for your attention!
2/8/2012
Mirko Pojer – LHC Performance Workshop – Session 5 – LS1
24