CERN Div./Group or Supplier/Contractor Document No.
CERN
TE/EPC
CH-1211 Geneva 23
Switzerland
EDMS Document No.
1312226
EDMS Project name :
Booster 2GeV
ELECTRICAL POWER CONVERTERS
GROUP (EPC)
Date: 20/08/2013
GROUP (EPC)
DOCUMENT
Booster 2GeV magnets connections
This report contains the description of the Booster magnets connections required for
Booster MPS supply upgrade.
Preliminary
Prepared by :
G.SKAWINSKI
F.BOATTINI
Checked by :
F. BOATTINI
-1-
Approved by :
History of Changes
Version
Date
Pages
Modified by
-2-
Modification descriptions
1.
BACKGROUND/ DESCRIPTION ............................................................ - 4 -
2.
BOOSTER MAGNETS ............................................................................ - 4 -
3.
EXISTING MPS MAGNET CONFIGURATION .......................................... - 5 -
4.
BOOSTER 2GEV MAGNET CONNECTION ............................................... - 7 -
5.
BOOSTER BUILDING LAYOUT .............................................................. - 9 -
6.
SWICHBOARD CABINET .................................................................... - 10 -
7.
CROWBAR SYSTEM ............................................................................ - 10 -
8.
CABLING LAYOUT .............................................................................. - 12 -
9.
ACTIVITY PLANNING ........................................................................ - 13 -
10. CONCLUSIONS .................................................................................. - 15 -
-3-
1. BACKGROUND/ DESCRIPTION
In frame of the LIU upgrade project the PS Booster will receive the new main power supply called from
now on MPS Booster 2GeV. The MPS booster 2GeV power supply will consist of the two independent
and identical units where each unit will supply the half of the existing Booster magnets. The existing
MPS power supply will work as the back-up in case of the failure of the new power supply.
The report proposes the switching logic that needs to be implemented in order to have such a feature.
The complete reconfiguration will be realized by acting on a single cabinet hereafter called “switching
cabinet” that in addition will allow a complete grounding of the magnets while power converters could
continue to operate in testing mode.
2. BOOSTER MAGNETS
The PS Booster is composed of 32 dipole magnets (192mH) and 48 quadrupole magnets (8.8mH). The
pictures of the Booster dipole and quadrupole magnets are given in Figure 1.
For every section there are two dipole magnets, two quadrupole focusing and one quadrupole
defocusing magnet. The Booster magnets are divided into 16 sections. Figure 2 shows the existing
magnets with the corresponding sections.
In addition, in the middle of the magnet chain there is the reference unit employed for the B-field and
current measurements. However this magnet is placed outside the tunnel in the building 361-1 and
surrounded by a metal fence).
Figure 1: PS Booster magnets – dipole (left) and quadrupole (right)
-4-
Pos.
Neg.
Section 16 BR-BHZ 161
BR-QFO 161
BR-QDE 16
BR-QFO 162
BR-BHZ 162
Section 1 BR-BHZ 11
BR-QFO 11
Section 2
Section 3
Section 4
Section 5
Section 6
Section 7
BR-QDE 1
BR-QFO 12
BR-BHZ 12
BR-BHZ 21
BR-QFO 21
BR-QDE 2
BR-QFO 22
BR-BHZ 22
BR-BHZ 31
BR-QFO 31
BR-QDE 3
BR-QFO 32
BR-BHZ 32
BR-BHZ 41
BR-QFO 41
BR-QDE 4
BR-QFO 42
BR-BHZ 42
BR-BHZ 51
BR-QFO 51
BR-QDE 5
BR-QFO 52
BR-BHZ 52
BR-BHZ 61
BR-QFO 61
BR-QDE 6
BR-QFO 62
BR-BHZ 62
BR-BHZ 71
BR-QFO 71
BR-QDE 7
BR-QFO 72
BR-BHZ 72
Section 15 BR-BHZ 152
BR-QFO 152
BR-QDE 15
BR-QFO 151
Spécial BR-BHZ 151
Section 14 BR-BHZ 142
BR-QFO 142
Anneau Booster
Section 13
Ejection
Injection
BHZ161
BHZ152
Section 12
Section 11
Section 10
Section 9
Section 8
BR-QDE 14
BR-QFO 141
BR-BHZ 141
BR-BHZ 132
BR-QFO 132
BR-QDE 13
BR-QFO 131
BR-BHZ 131
BR-BHZ 122
BR-QFO 122
BR-QDE 12
BR-QFO 121
BR-BHZ 121
BR-BHZ 112
BR-QFO 112
BR-QDE 11
BR-QFO 111
BR-BHZ 111
BR-BHZ 102
BR-QFO 102
BR-QDE 10
BR-QFO 101
BR-BHZ 101
BR-BHZ 92
BR-QFO 92
BR-QDE 9
BR-QFO 91
BR-BHZ 91
BR-BHZ 82
BR-QFO 82
BR-QDE 8
BR-QFO 81
BR-BHZ 81
Figure 2: PS Booster magnets
3. EXISTING MPS MAGNET CONFIGURATION
Each of the dipole magnet consists of four parallel paths (rings) denoted from 1 to 4. The rings 1 and 4
represent the external paths and are series connected. Similarly the internal rings 2 and 3 are also
connected in series. The two series need to be supplied in a slightly different way. This is due to the
fact that the external rings have a different magnetic configuration than the inner ones. In the present
MPS, an additional TRIM converter is used to correct the current in the external rings. The dipole
reference magnet has also 4 rings. However the rings are presently series connected.
The quadrupole magnets similarly to dipole magnets have four rings. However, all the rings are
connected in series and supplied from the same conditions.
The PS Booster magnets supply conditions are shown in Figure 3 where the connection between the
magnets and the converters are shown. The figure indicates also the type of cables/bus-bars used.
The main power connections with the tunnel are represented by 4 water cooled cables (WCC1 to 4 in
green in Figure 3) that connect the MPS and the reference unit with the rest of the magnets.
WCC1 and WCC2 are located in b271 close to the output filter area of the present MPS (Figure 4),
while WCC3 and WCC4 are below the reference unit in b361 (Figure 5).
Quadrupoles and trims converter cables are located directly below the respective converters.
-5-
Bending
1-4
WCC 1
BR MPS
WCC2
Bending
2-3
BR -MPS-TRIM
BUS BAR
WATER COOLED CABLE from TUNEL
CABLE
MAGNET CONNECTION
BR -QDE
BR -QFO
REF Magnet Cage
DCCT
QDE
WCC3
Reference
Bending
1- 2 – 3 - 4
WCC4
QFO
Figure 3: Existing Booster magnet configuration
Figure 4: WCC1 and 2 in front of the output filter area of the MPS
Figure 5: WCC3 and 4 under the reference unit
-6-
4. BOOSTER 2GEV MAGNET CONNECTION
The Booster 2GeV will be connected to the existing magnets. The Booster magnets will be split into two
independent circuits. In the new configuration, all dipoles and quadrupoles magnets are grouped as
shown in Figure 6 and are fed from independent power sources. The outer rings of the dipole magnets
will be connected in series with the QFO magnets, whereas the inner dipole windings will be connected
with the QDE magnets. This configuration will allow the total voltage for the magnets to be increased
to ±5kW (±2.5kV per circuit). This new modular approach will also eliminate the necessity of the
separate a trim converter for the external magnets coils.
The reference magnet has currently the series connection of all 4 paths. However for the Booster 2GeV
the reference magnet rings will be split and connected similarly to the dipole magnets i.e. outer and
inner rings groups. The magnet connector (a metallic bar) will be designed for a fast reconnection to
the original design (all 4 in series). The reconnection to the original design will be possible in case of a
Booster 2GeV failure. The schematic layout of the reconnection process is given in
Figure 7.
Figure 6: Booster 2GeV MPS magnet configuration
-7-
Bending
1-4
WCC1
C2
C1
2
C3
C4
Bending
2-3
WCC2
C27
C26
C2
BR MPS
2GeV CABLE from b245
WATER COOLED CABLE from TUNEL
CABLE
BR -MPSTRIM
C21
BR MPS A
2GeV
BR MPS B
2GeV
MAGNET CONNECTION
CONNECTIONS TO BE ADDED
DCCT A
BUS BAR
DCCT B
SWITCHING CABINET
C9
QDE
WCC3
Reference Magnet Cage
DCCT
C8
Reference
Bending
1 -4
C6
C7
Magnet
Connector
Reference
Bending
2 -3
Figure 7: Booster 2GeV magnet configuration
-8-
C5
C20
BR-QFO
2GeV
C19
C17
BR -QFO
C18
WCC4
QFO
C16
BR -QDE
C15
C11
C28
C10
C25
BR-QDE
2GeV
C14
C13
C12
5. BOOSTER BUILDING LAYOUT
The Booster MPS is placed in the building 271 and the building 361. The combine layout of the
both buildings (271-R and 361-1) is presented in Figure 8. The extra layers of the Power (red) and
Control (purple) elements have been added to the drawing.
Figure 8: Booster Building layout
-9-
6. SWICHBOARD CABINET
In order to connect the Booster magnets to both the new and the existing power supplies the
switching cabinet will be required. The cabinet will be placed in the building 271 next to the quadrupole
converters. The schematic representation of the connections points required is given in Figure 9.
BR- QDE 2GeV -
BR- QDE 2GeV +
`
`
BOOSTER MPS
`
`
QDE
BR- QFO 2GeV -
BR- QFO 2GeV +
2GeV BR MPS B -
2GeV BR MPS A -
2GeV BR MPS B+
2GeV BR MPS A +
QFO
QDE -
BR- QDE -
BR- QDE +
QDE +
QFO -
BR- QFO -
BR- QFO +
QFO +
Ref Magnet 2
Ref Magnet 4
BR MPS -
Bending 2
BR MPS +
Mag Connector
Bending 4
BOOSTER 2GeV
Reference
Magnet
MPS
Figure 9: Booster MPS / Booster 2GeV switchboard cabinet
The cables from the magnets (as indicated on the bottom labels – longer connections) will be
connected permanently to the switching mechanism. Each switch will have implemented 3 states as
follows:



Booster 2GeV connection
Booster MPS connection
floating connection
In the floating state there will be possibility to ground magnets. The converters will have grounding
implemented internally. Grounding system will be provided to the each section of the switching cabinet
as shown in the figure. The inter-locking system with padlocks will be implemented in order to ground
the system.
7. CROWBAR SYSTEM
In order to install the new switching board the removal/modification of the existing protection is
required. This operation will be the part of the switchboard project. The old diode – hydraulic switch
based crowbar system will be replaced by the thyristor based system as presently used in POPS
converter. The new crowbar will be placed inside the power cage next to the output filter. This removal
will give more space for the new switchboard cabinet. Both modifications are shown in Figure 10. The
- 10 -
existing bus-bar from the MPS power filter will be modified and will be connected to the new Crowbar
system to be installed in the power cage.
Figure 10: Crowbar - Switchboard 2GeV cables connection
- 11 -
8. CABLING LAYOUT
As presented in the Figure 9 the switchboard will reconnect the power supplies. To accomplish this
operation all the cables from the Booster magnets, Booster MPS and Booster 2GeV will have to be rerouted into the switchboard cabinet. The cabling layout for switching operation is presented in Figure
10. The existing bus-bar connections (except the power park) will be replaced by the cables to
minimize the work required and to improve the safety aspect as the cables will be placed under the
false floor. All connections circled in orange will be placed inside the switching cabinet in order to have
a single point to reconfigure the complete system.
Overall there are 28 power cables (named from C1 to C28 in
Figure 7) that need to be added.
Table 1 reports the characteristics of each set of above cable.
Cable
name
From
To
Estimated
length [m]
Current [A]
RMS
Isolation
[V]
C1
SB*
WCC1
5
2500
4000
New Cable
C2
BR MPSCrow Bar
SB
8
2300
4000
New Cable
C3
BR MPSCrow Bar
SB
6
2300
4000
New Cable
C4
SB
WCC2
5
2500
4000
New Cable
C5
Ref Bend 2-3
WCCC4
1
2300
4000
Existing Bus-bar
C6
Ref Bend 2-3
SB
24
2500
4000
New Cable
C7
Ref bend 1-4
SB
24
2500
4000
New Cable
C8
Ref bend 1-4
WCC3
15
2300
4000
Existing Bus-bar
C9
BR QDE
SB
9
300-120mm2
3000
New Cable
BR-QDE 2GeV
SB
25
430
2500
New Cable
C11
BR QDE
SB
9
300-120mm2
3000
New Cable
C12
BR-QDE 2GeV
SB
25
430
2500
New Cable
C13
Booster Tunel
SB
Unknown
Unknown
Unknown
C14
SB
WCC3
24
430
3000
New Cable
C15
SB
WCC4
24
430
3000
New Cable
C16
Booster Tunel
SB
Unknown
Unknown
Unknown
C17
BR-QFO
SB
9
300-120mm2
3000
New Cable
C18
BR-QFO
SB
9
300-120mm2
3000
New Cable
C19
BR-QFO 2GeV†
SB
25
430
2500
New Cable
C20
BR-QFO 2GeV
SB
25
430
2500
New Cable
C21
BR QDE
BR MPS
TRIM
6
100-50mm2
12/20kV
Existing Cable
C22
BR MPSCrow Bar
BR MPS
TRIM
20
100-50mm2
12/20kV
Existing Cable
C25‡
MPS 2GeV
SB
25
2500
2500
New Cable
C26
MPS 2GeV
SB
25
2500
2500
New Cable
C27
MPS 2GeV
SB
25
2500
2500
New Cable
C28
MPS 2GeV
SB
25
2500
2500
New Cable
C10
Remarks
New/Existing
Cable/To check
New/Existing
Cable/To check
Table 1: Connections to be provided
*
Switch Board/Cabinet
Booster2GeV ratings are based on the 43% increase estimation (2GeV/1.4GeV factor)
‡
Cable length from SB to MPS 2GeV is estimated currently as the length from SB to the border of the building 271.
- 12 †
9. CABLE RATINGS
9.1 MPS 2GEV
The cable connection between MPS 2GeV, SB and reference magnet shall have the following ratings:
Number of systems:
Approximate distance:
Rated current Ir (rms)
Rated voltage
Insulation test voltage
BIL (1.2/50 μs)
Min. clearances
4 : MPS 2GeV – SB
2 : SB – Reference magnet
25 m (from SB to the reference magnet)
60 m (from MPS 2GeV to SB)
2500 A for each system
(Pulses between zero and 5500 A every 0.9 s)
3.6 kV AC (corresponding to 5 kV DC)
30 kV DC (1 min)
60 kV
90 mm (acc. IEC 60071-1)
Due to high current the cable connection has to be arranged by multi-parallel connection.
The 400 mm2 Cu has been chosen to minimise the number of cables.
For the rating of the cables, the following reduction factors apply:
 k1 = 0.91 (ambient temperature 40 ºC)
 k2 = 0.85 (for grouping of cables)
 k3 = 0.85 (cable installation in closed conducts)
 k4 = 0.95 (for slight imbalances of DC resistance between the parallel cables)
ktotal = k1 x k2 x k3 x k4 = 0.625
Type
Thermal capacity
(100%) [A]
Factor k
Real thermal
Capacity [A]
number of
parallel cables
required per
2500 A system
400 mm2 Cu
827
0.625
516
4.85
9.2 QFO/QDE 2GEV
The cable connection between QFO/DQE 2GeV and SB shall have the following ratings:
Number of systems:
Approximate distance:
Rated current Ir (rms)
Rated voltage
Insulation test voltage
BIL (1.2/50 μs)
Min. clearances
4 : 2 converters having 2 cables
60 m : from 2GeV to SB
500 A for each system
(Pulses between zero and 500 A every 0.9 s)
3.6 kV AC (corresponding to 5 kV DC)
30 kV DC (1 min)
60 kV
90 mm (acc. IEC 60071-1)
ktotal = k1 x k2 x k3 = 0.657
Type
Thermal capacity
(100%) [A]
Factor k
Real thermal
Capacity [A]
number of
parallel cables
required per
500 A system
400 mm2 Cu
827
0.657
543
1
- 13 -
In order to minimise the unwanted effects of the magnetic field of the current, an even number of
cables need to be chosen. To obtain the greatest possible symmetry of magnetic fields, 6 cables should
be chosen for each of the 4 systems. The drawing below shows the possible layout of the 2 systems.
The installation of the cables will be in air (under false floor) on the cable ladders as shown below:
500
For cables installation from SB to The reference magnet only one cable ladder will be required.
- 14 -
10. ACTIVITY PLANNING
The installation of the switching cabinet and relative power cables shall be done before the beginning
of LS2.
The activity could be divided in two:
1) Installation of the switching cabinet and new crowbar system in b271 with all cabling concerning
the present MPS only. This activity could be performed any time before the beginning of LS1 in
4 weeks’ time.
2) Routing of all new MPS power cables up to the switching cabinet. This needs to be done once
the b245 (new building for the Booster 2GeV MPS) will be ready as cables will be routed
through a connection gallery. We will need these cables to be installed before the beginning of
LS2 in order to be able to make the tests on magnets (see new MPS testing schedule). This
activity could be done in 2 weeks.
Figure 11: Planning of Booster2GeV project
According to the present schedule (Figure 11), b245 should be ready by summer 2016. We could
concentrate the two activities during the winter shutdown of 2016-2017.
Since the four separate connections on the reference unit are not yet available, we could imagine, for
the only purpose of preliminary testing of the Booster2GeV new converters, that the reference unit is
completely bypassed with a temporary cable connection thus avoiding a long shutdown to fix the
reference unit connections.
11. CONCLUSIONS
Although the new MPS will be designed to generate 2GeV LHC cycles and despite the fact that the old
one cannot generate such pulses, we consider the possibility of a rapid changeover between the old
and the new MPS, of a considerable importance in case of severe fault of the new converter.
- 15 -