Transcript 04-Magnet_Readiness_Review_June_16v1x

Focus Coil
Electrical Configuration and
System Protection
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Circuit Configuration – Normal Operation
AMI 430 Controller (SS use AMI 420)
AMI regulates the output current
Ramp rate is set via the AMI to <30ma/s
DC contactor
AMI
430
Power
Supply
Focus
Coil
Energy
Absorber
Dump Circuit
Sorensen 250A power converter
Energy absorber is needed during ramp
down due to unipolar PSU
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Circuit Configuration – Magnet Quench
DC contactor
Power
Supply
AMI
430
3 ohms
Energy
Absorber
Dump Circuit
If a Quench is detected the DC contactor will opened
The magnet energy is then discharged into the dump circuit
Voltages of up to 700V can be generated across magnet
Earth connection at centre of resistors reduces voltage to earth
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Focus
Coil
Power Converter Rack Thermal Test
Fans Activate
4
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FC#1– Current Stability Measurement
FC1 Stability 21/5-22/5/2014 - Current measured at 1Hz over a 12.5 hours
Standard Deviation: 0.001829
180.204
Mean: 180.1903
FC1 Current 22/5/2014
200
180.202
180
160
140
180.200
180.198
120
AMI Controller – Stability Specification = 100ppm
100
AFC Current A
80
60
Drift over 12.5 hours < 10mA
180.196
Tested with FC#1
40
20
0
Current (A)
0
10000
20000
30000
40000
50000
60000
180.194
180.192
180.190
180.188
180.186
180.184
180.182
6000
11000
16000
21000
26000
31000
36000
41000
Time (s)
FC Current
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+50ppm from mean
-50ppm from mean
5
10 per. Mov. Avg. (FC Current)
46000
51000
RR2 Layout – rack allocation
QD System racks
Oxygen Depletion System
Auxiliary rack (Tracker & Diffuser)
FC & SS Control & Instrumentation racks
SS Ground Fault Protection rack
FC & SS Power Supply racks
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Power Supply and Instrumentation Racks
• Power supply system is air cooled and housed in
single rack
• Instrumentation is housed in a single rack including
temperature monitors, heater controller and helium
level indicator
• The equipment provides monitoring and protection
for the magnet
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SS and FC racks in RR2
Control System Philosophy
• VME system downloads the
system configuration via the
Ethernet connection.
• Ethernet also provides the
communication with the high
levels of the control system
• Allow parameters to be monitored
/ controlled via a GUI interface
• The VME provides analogues to
the plant via a serial interface
• CANBus interfaces up to 30
status modules
• Each status module contains relay
outputs for control and opto
isolated inputs for the interlocks
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Controls Interface
Super Conducting Magnet compressors
Power Supply racks
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Standardised Control
System with Plant
equipment
All control interfaces are standardised.
A number of control racks are located inside
the MICE Hall and rack rooms.
Each rack consists of VME crates, Canbus
modules and ADC/DACs.
These racks control - vacuum, compressors,
power supplies, tracker equipment, etc.
All controls equipment is modular and can
easily be replaced – spares are available.
DL Control System
Quench data logger
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Control Interface – Ramp Enable
Interlocks
Insulating-Vacuum
PPS Guardline A
Ramp Enable - Command
AMI 430 Controller
All interlocks are
latched into the
Control System
Volt free contact
activates ramp
enable
Any interlock will
activate the
ramp enable
Current automatically
ramped down to Zero
DC Contactor
will remain
closed
Once activated
controller is
locked
PPS Guardline B
PSU Rack Temperature
Earth Fault
Helium Level Low
PSU s/D Fault
Fast Ramp Down
SSD/SSU Turbo pumps
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Control Interface - DC Contactor
Interlocks
DC Contactor
Quench
Detected
Activated by Volt
free contact
DC Contactor - Command
Volt free contact
sent directly to
DC Contactor
DC Contacts are
latched closed
Volt free contact
also sent to
Control System
Can only be
opened by
Quench interlock
A Control system
failure will not
open DC contacts
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Opening DC
contactors at
nominal current
is highly likely to
cause a quench
Quench Protection – System operation
Voltage Tap Input
Amplified
Isolated
• 3 Voltage taps
• Resistive measurement
• Central tap amplified
• Outer voltage taps to
provide reference
• Signal is isolated from
the magnet
Quench Triggered
Relay de-energised
Compared
• Relay chain open circuit
• Magnet Circuit breakers
opened
• If signal is outside of
the specified range
• System Latched in the
quenched state
• Window comparator
used to compare signal
Quench Detection Crate
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Quench Detection Card
Quench Protection – System Operation (cont.)
System currently has two methods of setting the trip point.
• Through a fixed resistor which currently sets the tripping
threshold at 20mV
• Through a variable resistor which can set the tripping
threshold between 10mV and 600mV.
This function is switch selectable and is mounted on each card.
When a quench is detected several
actions happen at once.
• A signal is sent to activate the
dump circuit
• A signal is sent to control
system to alert the operators
•A signal is also sent to magnet
power supplies and other
equipment that may be affected
by the quench to power down
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Voltage Taps - Configuration
The voltage tap tripping voltages are set to 20mV for all of the HTS and
LTS comparisons and approximately 600mV for the coil comparisons.
• Four quench detection channels are connected across the HTS
and LTS leads
• Two channels are connected across the two coils of the magnet
as this was required to achieve an overlap
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QP System – Operating Characteristics
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Data Logging
Each channel is connected
differentially to each of the voltage
taps
Each input channel is rated for >1kV
There are 16 channels with one
allocated for the quench signal
2 of the channels will be used to
record quench triggers from the SS
magnets
The remaining 13 channels are used
to monitor the coils, LTS and HTS
leads
The processor stores 2 sets of
triggered data and is automatically set
via the ramp enable.
Currently only 1 minute of data is
recorded at 1ms intervals.
Will be soon updated to 8 minutes
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DC contactors open
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600mV threshold
Quench signal activated
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QP System – Key Operating Parameters
• Quench detection circuit is based on a proven and reliable 30 year
old design concept from the Paul Scherrer Institute (PSI).
• Each QD channel uses 3 voltage taps to monitor the voltage
differences progressively across the SC magnet.
• Each QD channel is rated for 1.5kV galvanic isolation between
channel and earth and 1.5kV channel to channel.
• The power supply crate contains commercially available power
supplies with built-in n+1 redundancy
• The Quench detector system has been used with the decay
solenoid and focus coil since early 2013 and has successfully
sensed over 20 quenches whilst training both FC’s during training
in R9 and finally in the Mice Hall.
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Protection Against Transient Overvoltage
MICE Hall main
Sub-station
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Transient Suppression
also installed on UPS
board
Transient Suppression installed on main distribution board.
Preventing lightning strikes and disturbances on the supply network
damaging equipment.
Transient suppression also being fitted on UPS board due to isolated
double conversion technology.
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Power Converters and Controllers
susceptibility to network disturbances
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FC - AMI 430 Controller – AC supply
threshold measured at 159V (spec -176V).
Once AC supply lost the AMI resets and
output is set to ZERO.
This will cause a fast ramp (circuit
components limited) – likely to cause a
quench – tested and verified.
DCCT supply failure is also likely to cause
a quench.
FC – Sorensen 250A PSU – if AC supply is
lost then a fast ramp will be initiated until
power returns.
Again likely to cause a quench.
Some of the recorded network
disturbances could have affected the
FC power converter.
(short duration – unlikely to cause
quench)
FC – AMI 430 Controller (SS use AMI 420)
FC - Sorensen 250A power converter (main)
230 Vac (operating range 176 - 264 Vac) – 76% of 230Vac
400 Vac (operating range 342 - 440 Vac) – 85% of 400Vac
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Rack Room 2 – UPS Inverter and Batteries
Two 30kVA UPS (inverter)
have been installed and
support Control, Power
Supplies, Vacuum and
Instrumentation in RR2.
UPS for
Critical Load
Batteries
The 2 x 30kVA UPS
operate in parallel and
share a common
battery pack.
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Emergency - Ramp Down
• A Ramp Down button is installed on the FC power
supply racks
• This button interface directly with the AMI 430
controller
• It will ramp the current to zero at the programmed
ramp rate. (between 10 and 30ma/s)
• Once activated the AMI controller is locked until
the current reaches zero
• Note – this is not a Fast Ramp Down as installed
on the SS magnets
• If the DC contactor was opened it would probably
quench the magnet
• A risk assessment concluded that quenching the
magnet should be avoided even during an
emergency
• Note - Emergency Ramp Down on the SS opens
the DC contacts and ramps the current to Zero
quickly
Racks installed in RR2
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Questions?
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