CERN Organisation Européenne pour la Recherche Nucléaire La protection des aimants lors de...
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A. Siemko AT/MEI RH23 RH87 R E52 RE48 R E58 RE62 RE72 R E78 RE82 RE12 R E88 RE22 RE18 RE28 R E42 R E38 R E68 U J4 6 UA47 U J4 7 RA47 UW 45 US45 U L4 6 TX46 U J4 4 UX45 RA43 UA43 UL44 U J4 3 RR53 U J5 3 UXC55 USC55 PM 54 PX56 RZ54 UP53 U J5 6 1 U J5 7 RR57 U J5 6 PM 56 UL56 TU56 UD62 U J6 2 U J6 3 PM 65 U J6 4 UA63 RA63 TD68 UP62 U L6 4 PZ65 PX64 U J6 6 U J6 7 U J6 8 UX65 UA67 RA67 TD68 UD68 UP68 UL66 TX64 UW 65 US65 P oin t 7 RR73 RR77 U J7 6 PM 76 TZ76 RA83 UA83 U J8 3 U J8 4 PM 85 PX84 PZ85 UX85 TX84 UL86 UA87 RA87 U J8 6 U J8 7 UW 85 US85 U L8 4 T I 8 U J8 8 PGC8 T J 8 RR13 U J1 3 RT12 U J1 4 US15 T I1 2 PM 15 PX14 UX15 U L1 4 U J1 2 LSS4 P M I2 U J1 7 U J1 8 U J1 6 T I1 8 RR17 PM 18 PX16 PX15 USA15 UL16 U J2 2 U J2 3 U J2 4 UA23 RA23 T I 2 PGC2 RA27 U J2 6 PX24 UX25 PM 25 UW 25 US25 UL24 UL26 U J2 7 UA27 ALIC E PZ 33 PM 32 U J3 2 U J3 3 RZ33 TZ32 CMS P oin t 6 LH C b ATLAS SPS PX46 PZ45 PM 45 RT18 P oin t 8 P oin t 5 P oin t 4 P oin t 3 .3 P oin t 3 .2 P oin t 2 P oin t 1 P oin t 1 .8 CERN Organisation Européenne pour la Recherche Nucléaire La protection des aimants lors de transitions résistives Andrzej Siemko, CERN/AT
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Transcript of CERN Organisation Européenne pour la Recherche Nucléaire La protection des aimants lors de...
RH23
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PGC8
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UJ 32 UJ 33
RZ33
TZ32
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LHCb
ATLAS
SPS
PX46PZ45
PM45
RT18
Point 8
Point 5
Point 4Point 3.3
Point 3.2
Point 2
Point 1Point 1.8
CERNOrganisation Européenne pour la Recherche Nucléaire
La protection des aimants lors de transitions résistives
Andrzej Siemko, CERN/AT
Contenu
L’architecture magnétique du LHC
Le phénomène du « Quench »
Le système « Quench Protection » de protection des aimants supraconducteurs en cas de transitions résistives
Aperçu sur l’opération du système cryogénique : protection hydraulique par vannes et lignes de décharge
Conclusion
L’architecture magnétique du LHC
LHC Sector
1
5
Main DC Power feed
3
Oct
ant
DC Power
2
4 6
8
7LHC27 km Circumference
Powering Sector:
154 aimants dipolaires,
environ 44 quadripôles;
Longueur d’environ 3 km
L’architecture magnétique du LHC se divise en huit secteurs principalement constitués de chaines d’aimants supraconducteurs, dipolaires ou
quadripolaires raccordes en série
RH87
RE78
RE82
RE12RE88
Point 7
RR73
RR77
UJ 76
PM76
TZ76
RA83
UA83
UJ 83
UJ 84
PM85
PX84
PZ85
UX85
TX84
UL86
UA87
RA87 UJ 86
UJ 87
UW85
US85
UL84
TI 8UJ 88
PGC8
TJ 8
RR13
UJ 13
RT12
UJ 14
US15
TI 12
PM15
PX14
UX15
UL14
UJ 12
LSS4
UJ 17
UJ 18
UJ 16TI 18
RR17
PX16 PX15
USA15
UL16
LHCb
ATLAS
SPS Point 8
Point 1
Sectorisation du LHC
Sector 8-1
Powering Sector:
~210 cold circuits 190 orbit corrector circuits ~10 warm circuits
Powering Subsectors:
correspondent en général aux cryostats indépendants, facilitent la mise en opération
arc and even matching section
inner triplets and odd matching section
warm magnets
Sector 7-8
L’architecture magnétique du LHC
LHC Arc - Cellule élémentaire
23 cellules (2.5 km) dans chaque secteur
A. Siemko AT/MEI Les Journées Thématiques AFF-CCS, CERN, 10-11 Avril, 2008
Le phénomène du «quench»
The superconducting state is defined by the critical surface B (T), J (A/mm2), T (K)
Magnets operate in conditions corresponding to a point beneath the critical surface T=Top, J=Jop, and B=Bop
Increasing the current in the magnet the critical surface is crossed and a small volume V of superconductor becomes normal
The volume V starts dissipating heat because of Joule effect, and its temperature increases
LHC Dipol
e
Le «quench»: Marge d‘opération d‘un aimant supraconducteur dipolaire
Temperature [K]
App
lied
field
[T]
Superconductingstate
Normal state
Bc
Tc
9.2 K
B [T]
Temperature [K]
QUENCH
1.9 K
8.3 T
0.54 T
NbTi
A. Siemko AT/MEI
Des perturbations provoquer transitions résistives
Electrical disturbances Non uniform current distribution in Rutherford cables Strain dependence of critical current, flux jumps
Energy release in the magnet due to the beam losses Beam losses from non-perfect setting up of cleaning Fast beam losses Beam gas scattering
Mechanical disturbances Conductor motions Structural disturbances: micro-fractures, cracks, etc.
Pendant le fonctionnement, des perturbations peuvent entraîner une brusque transition résistive de l'aimant
A. Siemko AT/MEI
La propagation des transitions résistives
In LHC dipoles a quench propagates along s.c. cables with average velocity of: 20-30 m/s at 8.34T >500ms to quench one turn 50-70 cm/s at 0.54T >21s to quench one turn
At nominal field quench propagates transversally (turn-to-turn) every ca. 10ms
Current after quench
0
2000
4000
6000
8000
10000
12000
-0.05 0.15 0.35 0.55
Time [seconds]
Curr
ent [
A]
Approximation par Gaussienne
Courant dans le dipôle après une transition résistive
60
250
65
75
85
95
105
125
140
Quench provoked by spot heater
I=12850A ; T=1.90 K Tht~249 K
DThb~110 K
Quench origin
Quench origin (Spot heater)
Le «quench»: une montée de température Une fois que les chaufferettes de protection sont
allumées, en moins d’une seconde l’énergie est dissipée dans l’aimant
RH23
RH87
RE52RE48
RE58
RE62
RE72
RE78
RE82
RE12RE88
RE22
RE18
RE28
RE42
RE38
RE68
UJ 46
UA47
UJ 47RA47
UW45
US45
UL46
TX46
UJ 44
UX45
RA43
UA43
UL44
UJ 43 RR53
UJ 53
UXC55
USC55
PM54
PX56
RZ54UP53
UJ 561
UJ 57RR57
UJ 56
PM56
UL56TU56
UD62
UJ 62
UJ 63
PM65
UJ 64
UA63
RA63
TD68
UP62
UL64
PZ65
PX64
UJ 66
UJ 67
UJ 68
UX65
UA67
RA67
TD68
UD68
UP68
UL66
TX64
UW65 US65
Point 7
RR73
RR77
UJ 76
PM76
TZ76
RA83
UA83
UJ 83
UJ 84
PM85
PX84
PZ85
UX85
TX84
UL86
UA87
RA87 UJ 86
UJ 87
UW85
US85
UL84
TI 8UJ 88
PGC8
TJ 8
RR13
UJ 13
RT12
UJ 14
US15
TI 12
PM15
PX14
UX15
UL14
UJ 12
LSS4
P M I 2
UJ 17
UJ 18
UJ 16TI 18
RR17
PM18 PX16 PX15
USA15
UL16
UJ 22
UJ 23UJ 24
UA23
RA23
TI 2
PGC2
RA27
UJ 26
PX24
UX25
PM25
UW25US25
UL24
UL26
UJ 27 UA27
ALICE
PZ 33
PM32
UJ 32 UJ 33
RZ33
TZ32
CMS
Point 6
LHCb
ATLAS
SPS
PX46PZ45
PM45
RT18
Point 8
Point 5
Point 4Point 3.3
Point 3.2
Point 2
Point 1Point 1.8
La protection de circuits supraconducteurs du LHC
1700 Electrical Circuits
5000 Protection Channels
1000 Beam Loss Monitors
Energie stockée dans les aimants supraconducteurs
E dipôle = 0.5 L dipôle I 2dipôle
Avec les valeurs d’opération:
E dipôle = 7.1 MJ
Pour les 1232 dipôles dans le LHC:
E dipôle total = 8.65 GJ
Ordres de grandeur
~9 GJ (1232 dipôles du LHC à 11850A)…
Correspondent à l’énergie de 1700 kg TNT pour chauffer et fondre 11000 kg de cuivre produite par une centrale nucléaire en 10 s
R
R R
R
Quench Protection System (QPS)
1. Detection.
2. Propagation artificielle de la transition
V
3. Isolation de l’aimant qui transite
4. Ouverture des disjoncteurs de puissance
5. Extraction contrôlée de l’énergie de la chaîne =104s
A. Siemko AT/MEI
Détection de transition résistive
dt
diLirv .1.11
dt
di.2Li.2r2v
dt
di.2L1Li.2r1r2v1v
= 0 si supraconducteur = 0 si les tensions se compensent
A. Siemko AT/MEI Les Journées Thématiques AFF-CCS, CERN, 10-11 Avril, 2008
Électronique de protection des aimants supraconducteurs
Analog bridge detector based on state of the art instrumentation amplifiers
(2 out of 2) || (2 out of 2) hardwired multi-channel evaluation scheme
Radiation tolerant Adjustment free – fixed threshold
detector Digitally isolated interface –
detector circuit on magnet potential
On-board data acquisition system
Cost efficient (2500 circuit boards in LHC)
Wheatstone bridge
Galvanically isolatedinterface to interlocks
and supervisionOn-board dataacquisition system
Analog detection system
Time discriminator
G=100100 mV
LOW =Quenchoccurred
Timediscriminator10 ms
VoltageReference
Interlock Current Loop
WheatstoneBridge Output
DAQ &Test
Acquisition & MonitoringController
Quench HeaterPower Supplies
100 mVG=100
Isolated AC/DCConverter 230V Redundant UPS
A. Siemko AT/MEI Les Journées Thématiques AFF-CCS, CERN, 10-11 Avril, 2008
Électronique de protection des aimants supraconducteurs
High precision digital systems with low detection threshold (UTH = 3 mV) for the protection of HTS leads
Fast DSP based systems for the protection of corrector and insertion region magnets (including superconducting busbars) and the inner triplets
Both systems integrated into so-called Global Protection Unit Simultaneous and independent
protection of up to 4 superconducting circuits
Units control and trigger associated quench heater power supplies
Type A Global Protection Unit for up to 4 corrector magnet circuits. The unit is attached to dedicated 600 A current sensors.
A. Siemko AT/MEI Les Journées Thématiques AFF-CCS, CERN, 10-11 Avril, 2008
Électronique de protection des aimants supraconducteurs
Active protection of superconducting magnets with quench heaters Function based on a
thyristor triggered capacitor discharge
6200 units in LHC
Extensive R& D program Component lifetime
(Aluminium electrolytic capacitors)
Radiation tolerance (main concern: thyristors)
Electromagnetic susceptibility
Large number of devices
A. Siemko AT/MEI
Diodes de «by-pass» installées dans le bain d’hélium à 1.9 K
Heater firing circuitsCB
L77 L78 L79 R79 L153 L15475 mΩ
PC
FWDCB
75 m ΩI
L1 L2L76
Heater firing circuits
Simplified scheme with individual by-pass diodes for one LHC-Sector
A. Siemko AT/MEI Les Journées Thématiques AFF-CCS, CERN, 10-11 Avril, 2008
Diodes de «by-pass»
La protection des circuits d’aimants
Updated on 16-Jul-06 Version 1 600A EE CERN - AT / MEL 1
Energy ExtractionEnergy Extraction
A. Siemko AT/MEI
Energy Extraction Systems
The 200 Energy Extraction Systems represent 296 Tons of Components
13 kA 600 A
A. Siemko AT/MEI
Disjoncteurs électromécaniques
A. Siemko AT/MEI
Résistances de décharge
A. Siemko AT/MEI Les Journées Thématiques AFF-CCS, CERN, 10-11 Avril, 2008
When will Energy Extraction be activated in the LHC? Energy Extraction is a part of the normal operating procedures
in the LHC machine
Energy Extraction will NOT be used for the ordinary de-excitation of the magnet chains. Energy recuperation is possible in some of the circuits (e.g. in the Main Dipole circuits). Operating the converters in inversion will allow power feed-back to the Mains Grid.
Energy Extraction will be used in following cases: In the event of a quench in a magnet coil, a superconducting busbar
or a current lead In the event of a risk of damage to other components in the power
circuit (e.g. no water flow for a certain time in the 13 kA water-cooled cables or problems in the by-pass crowbar system or failure in the extraction switches)
A. Siemko AT/MEI
«Quench» - Protection hydraulique
A. Siemko AT/MEI
Protection hydraulique par vannes et lignes de décharge
A. Siemko AT/MEI
«Quench» - Protection hydraulique
18 bar
2 min.
3 h
Pressure build-up
Pressure discharge
A. Siemko AT/MEI
«Quench» - Protection hydraulique modélisation de
processus
A. Siemko AT/MEI
«Quench» - Protection hydraulique modélisation de
processus
Energy balance Time
kJ kW (av.) s
1st phase 285 1074 0-0.26
2nd phase 217 46 0.26 - 4.7
3rd phase 3382 16 4.7 - 180TOTAL 3883 22
Magnet structure
Heat
Co
i
Bulk Helium
m = 0
QRV closed
Phase 2 - bulk helium heating
Magnet structure
HeatC
oi
Bulk Helium
m > 0
QRV open
Phase 3 - bulk helium heating and discharge
Magnet structure
MagneticEnergy
Heat
Co
i
Work
Virtual Adiabatic Piston
Confined Helium
Bulk Helium
m = 0
QRV closed
Phase 1 - adiabatic compression of the bulk helium
Conclusions
The LHC as a project, it is much more complex and diversified than any other large accelerator project constructed to date
The LHC magnet protection system is as well the most complex and diversified system of this type ever built
The performance of the protection system is of fundamental importance for the collider and must be thoroughly validated before proceeding to run with significant stored beam energy
Commissioning of the protection system in the first sectors is ongoing and already demonstrated correctness of the functional principles and required performance of the equipment
Remerciement K. Dahlerup-Pedersen R. Denz A. Vergara
Merci de votre attention
