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ESRF PSG safety for equipment and
personal related to power converters
2nd POCPA 15th of June 2010
Jean-François Bouteille
ESRF Power Supply Group equipment
• 15 main families power supplies from 100kW up to 1MW.
• About 500 corrector channels from 5W up to 200W
• 3+2 oscillating families for the 10 Hz booster ( 3 White
circuits )
• About 50 intermediate power supplies for the transfer
lines from 20W up to 2kW
• One big conditioning building (HQPS) for 50Hz 20kV
mains 9.3MW,11.6MVA
Jean-François Bouteille 2nd POCPA June 15th 2010
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ESRF PSG talk summary
•Power supply equipment safety
• Electrical
• Mechanical
• Environmental
•Personal safety linked to power
converters
• Status of procedure for accelerator personal
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Power supply equipment safety
• 2 main aspects:
• Intrinsic equipment protection
• General indirect equipment protection
• Intrinsic protection.
• Based on internal damages induced by component faults
• Energy damping
• Water flooding damages
• Based on direct surrounding conditions
• Mains disturbances
• Temperature, humidity
• General indirect equipment protection
• Based on the accelerator protection (machine safety),
• Dipole converter as safety device for personal radiation safety
• Fast mechanical shutter ( beam dump)
Jean-François Bouteille 2nd POCPA June 15th 2010
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Intrinsic Protection
• Specificity to accelerators:
• We are responsible to procure a set of converters with long running
capacity, without maintenance or repair. One hour of beam dump is rated
17k€ in 2009.
• The lifetime of equipment for large accelerators, is intended to be far
above the one for public device found on the world market.
• As a consequence the design rules impose to envisage the energy
damping mechanism to be fully safe. This means that each energy
storage component needs to be carefully designed. Complex
environment with multiple energy sources pushes to be cautious.
• Most of the converters are water cooled. The main advantage is the
electrical efficiency but: electricity and water are not compatible. This
point needs to be specially treated.
Jean-François Bouteille 2nd POCPA June 15th 2010
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Example of design guide
• Water
• Flow controller needs to be at the exit of the water cooled device.
• The sensitivity of flow controller needs to be better than smallest
flow in parallel circuits!
• Electricity
• Capacitors are destroyed by over charging ( to much current
discharge as well as to much absorbed current ) follow-up of the
serial impedance is regularly performed.
• Inductors force current to flow at tremendous voltage levels. (ex: DC relays
contacts)
• Input and output circuits need to be carefully watched !
• Public mains characteristic is subject to large excursion. This is, in most
accelerators, the main source of converter unavailability. (ESRF uses HQPS to clean
the public mains)
• Evacuating the stored energy from the load is to be considered with a
thorough analysis of the conditions and configurations. (10Hz booster power supplies)
Jean-François Bouteille 2nd POCPA June 15th 2010
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Particular case of AC or pulsed power supplies
When 2 circuits independent AC powered (10Hz ) use the
same cable trays inside long distance in tunnel, the
coupling coefficient of the air transformer cannot be
discarded, safety wise.
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Power supply Personal safety
• 2 main aspects:
• Intrinsic local worker protection
• General indirect worker protection
• Intrinsic worker electrical protection.
• Electrical maintenance of converters ( preventive or curative)
• Based on direct surrounding conditions
• Voltage levels ( VLV, LV, HV) defining the procedure to operate
• Additional safety conditions, mechanical, thermal, etc…
• General indirect personal protection
• Work of any kind inside the tunnels on or in the vicinity of the loads
• The vicinity understood according to the French electrical regulation
• Lock-in , lock-out, tag-in tag-out procedures.
Jean-François Bouteille 2nd POCPA June 15th 2010
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Intrinsic worker electrical protection
• Electrical maintenance of converters ( preventive or
curative)
• At ESRF, like at CERN, we have chosen to avoid and forbid all
work under voltage.
• As a consequence the full sequence of Lock-Out , Tag-Out
(LOTO) is applied by trained people dully authorized by the
company.
• The reminding risk is the tuning work. This means debugging or
adjusting is necessary when the material is alive.
• Special training is necessary to avoid people electrical shock, and
arc burn effects.
• Most of the time isolating tools or no contact measurement reduce
the risk linked to live contacts
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General indirect personal protection
• Work of any type inside the tunnels on or in the vicinity of the
loads.
• The use of the lock-out tag-out “consignation” has to be strictly
followed. This means that the actions intervention and lockout, have
to be temporary married. Intervention without lockout is risky,
together lockout without intervention is also risky.
• The vicinity understood according to the French electrical
regulation (see graph)
• Definition of the zone according to the voltage level.
• Lock-in , lock-out, tag-in tag-out procedures. These procedures
are one element inside the general authorization to work inside
the tunnels.
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Classification of voltage levels
• These values are between any wires, including earth conductor
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• Next year, (2011) these zones will be understood also outside
and not only in specific rooms reserved to electricians
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Mechanical protection
• The electrodynamic forces are often
not correctly anticipated.
• Video
• HQPS case with 65kA short circuit
between 2 x 800kVA alternators and a
1600kVA transformer
• Nobody was present in the room but
the consequences could have been
dramatic!
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Conclusion
• These 4 aspects of the safety
related issues make our job on
one hand very interesting and in
other hand push us to realize
our large responsibility.
• Thank you for your attention
Jean-François Bouteille 2nd POCPA June 15th 2010
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