Download McGilvery ARW-UPS

A Large Scale UPS for the
Australian Synchrotron
Don McGilvery
Lead Accelerator Operator
OUTLINE OF THIS PRESENTATION
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About the Australian Synchrotron Light Source
Reliability and Causes of Lost Beam Time
Types and causes of Power Interruptions
Possible ways to mitigate power interruptions
Use of Power Quality data to understand how systems fail
Comparison of UPS technological solutions
Ups and Downs of a UPS
Installation Progress
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AUSTRALIAN SYNCHROTRON LIGHT SOURCE
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3GeV electron Light Source
200mA stored beam (fill on fill)
216m circ Storage ring
Full energy Injector
Currently 9 beamlines
Operation commenced in 2007
Supports ca. 2500 Users from
Australia and New Zealand
Scheduled 5000 hours of User
Beam per year
$35M support facility upgrade
program in progress
Seeking Funding for a further
10 beamlines
MAJOR SUPPORT FACILITY UPGRADE
1.
2.
3.
4.
5.
6.
Medical and
Imaging far field
facilities
National Centre for
Synchrotron
Science
User Accomodation
Building
Office expansion
Technical Support
Facility (Workshops
and Engineering
Building)
Switch Room
Extensions
1
3
4
6
2
5
USER BEAM AVAILABILITY
Mean Time Between Failures and Mean Down Time
LOST USER BEAM TIME BY FAULT CATEGORIES
This equates to a cost of about $560,000.00 in lost productivity due to unreliability of
the incoming power feed
AUSTRALIAN SYNCHROTRON POWER FEED
The Australian Synchrotron receives its power via a dedicated underground 22KV power
feed from a local substation. This in turn receives its power via 66KV feeders from a major
substation on the Eastern Australian Power Grid. This grid serves 80% of Australia’s
Population across an area of about 2M square kilometers.
While the grid is very resilient it is possible for large disturbances to reflect across
significant areas of the grid.
Often a single event will cause two voltage sag events. When a fault occurs on the Power
Grid an automatic circuit breaker will open removing the fault. The voltage returns to normal.
Several seconds later the circuit breaker will close again to see if the fault has gone away.
If the fault is still present a second dip is seen before the breaker permanently opens.
LIST OF CAUSES IDENTIFIED BY POWER SUPPLIER
Fault
Frequency
Average Lost User Time
Total Lost User Time
22kV site feed fault caused by
– another HV customer
1
– a bird strike
5
02:37:10 (4 events)
10:28:39
– conductor clash
3
13:19:29 (1 event)
13:19:29
– fallen trees
2
– lightning strikes
2
08:13:44 (1 event)
8:13:44
– network equipment failures
7
03:05:49 (4 events)
12:23:17
– network equipment switching
1
– a possum
6
02:12:38 (4 events)
8:50:32
– unknown
1
– a vehicle collision
3
00:26:59 (1 event)
0:26:59
– yet to be reported
15
00:27:44 (15 events)
6:56:55
46 total
DISTRIBUTION OF VOLTAGE SAGS
% DROP vs DURATION
Events between the lines are defined as acceptable by the Power Regulator
3D Magnitude-Duration Histogram
COMMON FAULTS CAUSED BY VOLTAGE SAGS
Faults cased by disturbances
@ 95% Storage Ring RF systems trip (SRRF) [TR4]
@ 90% Storage Ring Dipole Power Supply (over current on voltage recovery) [TR6]
Refrigeration Chillers in Cooling Water Plant (overcurrent pulses) [TR2/5]
@85% SRRF Low Conductivity Water pump (ramps down /up) trips SRRF
@80% most other devices (particularly magnet power supplies) not on local UPS systems
Power requirements
TR2 = 1160kW at 0.95 power factor
TR4 = 1000kW at 0.95 power factor
TR6 = 1020kW at 0.95 power factor
22kV switch board
Tr1
Tr3
UPS-T3 (Optional)
MSB-T1
(Booster and BTS)
Bus-tie
(New)
MSB-T3
(Linac and LTB)
Modifications to MSB-T1 and MSB-T3
(Auto bus-tie scheme)
Tr2
Tr5
Tr5
UPS-T2 (LCW / comp.
air)
MSB-LV-NT (T2)
(Building light / power
and LCW / compressed
air)
Bus-tie
(Existing)
MSB-LV-NT (T5)
(Building
mechanical plant)
Modifications to MSB-LV-NT
(PLC reprogramming)
Tr4
Tr6
UPS-T4 (SRRF)
UPS-T6 (SR MPS)
MSB-T4
(Storage ring RF)
MSB-T6
(Storage ring power
supplies and
equipment racks)
WAYS TO REDUCE IMPACT OF VOLTAGE SAGS
1. Make systems more resilient to voltage sags.
We have been investigating each system to identify how the disturbances causes
the device to fail. Use Power Quality meters and look for machine variables which
can mirror voltage transients. We have a project to replace the SRRF analog Low
Level Electronics with a digital solution to improve the transient response.
(we have found that our Storage Ring Dipole power supply has internal current
monitors which are a very sensitive measure of mains voltage variations)
2. Reduce cross talk between devices.
We have a major project to retrofit an earth grid and fix many of the earthing
anomalies
3. Link into the Power Grid at a stiffer point (66KV)
This would be an expensive option and provide limited improvement as many
faults propagate at this level.
4. Install UPS systems to reduce or eliminate voltage sags on critical (or all
equipment)
ANALYSIS OF AN EVENT (10% SAG for 700 ms)
•This event caused the SRRF and the SR
dipole magnet power supply to trip
•Voltage trace shows a Sag to 90% for 700ms
•Current shows AVR held up RF for 200ms
•2 SRRF cavities tripped at 200ms
•The other 2 cavities tripped when the
incoming power feed recovered
•The modulation anode drive currents and
•RF drive voltages give us information about
•the feedback loops on the RF systems
ANALYSIS OF SHORT SAG
Power Supply Feed [T6]
•Voltage Sag,
•Electrical storm,
•83% min, approx 200msecs
•Chillers faulted,
•no power supplies faulted,
•SRRF702 tripped.
•Standby chiller started without faulting.
ANALYSIS of SHORT SAG (cont)
Cooling Plant Power Feed [T2/5]
Brown out,
Electrical storm,
83% min,
approx 200msecs
Chillers faulted,
Standby chiller started
without faulting.
ANALYSIS of SHORT SAG (cont)
SRRF power feed [T4]
The current to the SRRF
System dropped from 1.4KA to
about 1.0KA immediately
following the first dip
indicating the RF systems
tripped early in the transient
Even though we are trying to make
The various systems more resilient
It is unlikely that we will be able to
Achieve adequate improvement to
eliminate most power related beam
trips
UPS OPTIONS
• Providing at 22KV or at 415V
• Using off-line or double conversion
• Using Phase Compensation
• Using Batteries or Capacitors
• Using Kinetic Energy, with either low or high speed flywheels.
• Most common solutions are designed to provide ride through
capabilities for computer systems such as Banks or booking
systems while standby generators start up. The voltage stability and
harmonic content requirements are much greater for the Australian
Synchrotron.
PROVIDING PROTECTION at 22KV or 415V
• To provide the UPS at 22KV would simplify installation as one
system could protect all the susceptible systems.
• Providing protection at 415V requires at least 3 separate UPS
systems with no chance to load share. ie Each system needs to be
sized large enough to handle its peak load.
• Most solutions rely on extensive semiconductor switching capability
which would require down and up conversion to provide at 22KV
• This would add to the cost and result in increased power losses and
reduced efficiency.
• Most suppliers recommended strongly against this option
USING OFFLINE ENERGY STORAGE
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Most computer backup systems can tolerate short (<100ms) sags to 90% or less of
the incoming mains voltage.
The UPS system is set up to store energy offline and be able to switch in to maintain
a continuous power feed in the event of a voltage sag.
In normal operation power passes straight through the UPS system and efficiencies
of 98% or greater are possible
When the incoming mains drops below the threshold (typically 90% but could be as
high as 95%) the energy storage system maintains the output voltage. 10%
transients and phase discontinuities are common.
With a large sag the incoming mains may be disconnected for a short time before
being restored.
These systems generally do not offer over voltage suppression
USING DOUBLE CONVERSION
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With double conversion all power passes through the UPS regulation
circuits. This can provide very high voltage stability (>95%) during both
voltage and current transient conditions.
These systems will often disconnect the incoming mains as soon as
transient conditions are detected and will resynchronize with the mains
voltage and phase before reconnecting. This ensures good voltage and
harmonic stability. The reconnection time can be 5 seconds or more.
These systems will suppress over voltage as well as undervoltage
conditions
They rarely achieve efficiencies greater than 95% which can
significantly increase running costs.
USING BATTERIES OR CAPACITORS
• Due to the very high maintenance and replacement cost we made
the decision to not consider battery based solutions
• The lowest cost solution is using capacitor banks to store the
charge.
• The systems typically provide up to 1 second ride through capability
• While they could provide ride through power for the duration of most
sags they cannot economically proved sufficient power for a
continuous conversion system.
• These systems are common for IT solutions.
USING KINETIC ENERGY
• The incoming mains runs a motor/generator.
• Power is stored using either large slow speed flywheels or smaller
high speed flywheels.
• Multiple flywheels can be connected in parallel to increase current or
hold up time
• All power passes through the regulation circuits
• Vibration and bearing degradation can be an issue
• Frequency resynchronization time can be many seconds
UPS and DOWNS of a UPS
• A UPS should provide protection from most incoming voltage
transients
• This should reduce the time lost by users and improve the science
quality and output
• This comes at a cost of increased power consumption due to the
95% (or less) efficiency of a double conversion UPS system and
extra cooling
• There is still a possibility of voltage transients tripping the beam from
noise from unprotected systems (the injection system)
• There is another system requiring maintenance
• There is potentially more vibration from the flywheels.
We have used the Diesel Generator (located adjacent to the new
UPS building) as a vibration test machine and see no detectable
increase in noise on the stored beam or close beamlines. Use of
heavy compacting machinery during recent construction has been
very visible on the beam (50um ,15-25Hz noise on beam)
PROGRESS WITH THE UPS
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A Contract for 3 flywheel based double conversion UPS systems has been
placed to protect the SRRF, SR magnets and cooling water plant.
The Switch Room Extension building is almost complete
Cable trays, cabling and interconnect boards will be installed over the next
month
The UPS systems will be installed between May and September
Commissioning should occur during the September maintenance shutdown
The UPS building last Friday