RACK POWER SUPPLY AND CONTROL
as proposed by ST-EL.
J. Pedersen,
ST-EL
Presentation,J.C.O.B., 05.06.2002
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SUMMARY
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Introduction
Power equipment
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ALICE and LHC-B.
ATLAS and CMS.
Control possibilities
Cost
Conclusion
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INTRODUCTION
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The aim:
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ST-EL provides a state of the art power supply with
adequate monitoring.
The experiments can control the power distribution
to their racks.
The experiments can define trip conditions for the
racks through an “External interlock”
The experiments can view the status of the power
distribution of the racks
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POWER DISTRIBUTION EQUIPMENT
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ALICE and LHC-B.
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Recuperate existing HAZEMEYER switchboards.
Relatively voluminous, cabling through false floor.
ATLAS and CMS.
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Use new “CANALIS” style distribution equipment.
An isolated bus-bar system. Very dense
construction, thus well suited for installation in areas
of limited space.
Routed in steel housing, thus very low field
emissions.
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POWER AVAILABILITY
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Basic assumption: The racks will be fed from
the normal supply, i.e. neither diesel nor UPS
back up.
If a short-break supply ( diesel back-up ) or a
no-break supply ( UPS with or without diesel
back-up is required, this will come with a price
tag attached to it.
The experiments should analyse their needs
for back-up carefully.
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RACK POWER EQUIPMENT
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Try to avoid single phase switch mode power
supplies with simple capacitive input stages.
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This type of equipment means heavy 3rd harmonic
pollution of the power network. It requires de-rating
of the power equipment and may require filtering:
Increased cost
If possible, use three phase or single phase
equipment with sinusoidal input current and a
power factor close to 1.
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CONTROL POSSIBILITIES
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The control interface equipment between
ST-EL and the experiments will be based on
a PLC solution.
The experiment will be able to command the
individual feeders ON/OFF. ST-EL will not
retain a command possibility.
The experiment will be able to monitor the
status of each feeder
The experiment will be able to use an
external interlock ( A 48 V, potential free
contact, normally closed, open on fault )
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COST
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Cost is incurred by:
Re-vamping of the HAZEMEYER equipment
Purchase of CANALIS-type equipment
Installation and cabling*) work
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HOW MUCH WILL IT COST?
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I DO NOT KNOW !
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ANYWAY, YOU WILL HAVE TO PAY FOR
IT
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*) ALICE and LHC B mainly
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POTENTIAL PROBLEMS
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Will the equipment work properly in high
magnetic fields?
Field emission by the power distribution;
This is seen as a possible problem by
certain people in ATLAS. ST-EL believes
that a bus-bar system as described here,
can alleviate these fears.
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CONCLUSION
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ST-EL can supply a powering system for the
experimental electronics racks that seem to fulfil
the requirements of the experiments.
ST-EL will have to:
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Establish an overview of existing HAZEMEYER
equipment and cost the re-vamping of it.
Launch a call for tenders for “CANALIS” like equipment
Estimate installation costs
To allow ST-EL to do this in a sensefull way the
experiments will have to define their needs,
including needs for safe power!
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