1. ESRF PSG safety for equipment and personal related to power converters 2 nd POCPA 15th of June 2010 Jean-François Bouteille

2. Jean-François Bouteille 2nd POCPA June 15th 20102 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

3. Jean-François Bouteille 2nd POCPA June 15th 20103 ESRF PSG talk summary Power supply equipment safety Electrical Mechanical Environmental Personal safety linked to power converters Status of procedure for accelerator personal

4. Jean-François Bouteille 2nd POCPA June 15th 20104 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)

5. Jean-François Bouteille 2nd POCPA June 15th 20105 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. Intrinsic Protection 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.

6. Jean-François Bouteille 2nd POCPA June 15th 20106 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)

7. Jean-François Bouteille 2nd POCPA June 15th 20107 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.

8. Jean-François Bouteille 2nd POCPA June 15th 20108 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.

9. Jean-François Bouteille 2nd POCPA June 15th 20109 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

10. Jean-François Bouteille 2nd POCPA June 15th 201010 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.

11. Jean-François Bouteille 2nd POCPA June 15th 201011 Classification of voltage levels These values are between any wires, including earth conductor

12. Jean-François Bouteille 2nd POCPA June 15th 201012 Next year, (2011) these zones will be understood also outside and not only in specific rooms reserved to electricians

13. Jean-François Bouteille 2nd POCPA June 15th 201013 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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16. Jean-François Bouteille 2nd POCPA June 15th 201016 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

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