Contents V Montabonnet Safety during Hardware Commissioning 18

Contents V. Montabonnet - Safety during Hardware Commissioning 18 October 2007 Contents o o o o Electrical circuits in the LHC context Electrical Hazards Preventions Safety Training Habilitation Consignation Flowchart for LHC work 1

LHC Electrical Circuit o Power converters supply: V. Montabonnet - Safety during Hardware Commissioning 18 October 2007 o o Cold circuits: UA, RR, UJ [High Current] Warm Circuits: SR [High Voltage] 18 k. V QHPS 400 V [UPS] QHPS Water AC DC EE system Power Converter AC DFB DC 18 k. V / 400 V Power Converter EE system Cold Circuits 2

Electrical Hazards V. Montabonnet - Safety during Hardware Commissioning 18 October 2007 o Electrical shock due to contact with energized piece n AC side o o o n 18 k. V for the Main Dipole and Warm Magnet converters 400 V for all the other converter types 400 V UPS for the Electronics of the high current converters (> 2 k. A) DC side (Differential Voltage) o o o Up to 950 V for the warm magnets 180 V for the Main Dipole Converter during a ramp < 20 V for all the other converters AC DC Power Converter 3

Electrical Hazards V. Montabonnet - Safety during Hardware Commissioning 18 October 2007 o Electrical shock due to contact with energized piece n DC side (Common Mode Voltage) o o Common mode of 10 V in normal operation Voltage / Earth could be high during Energy Extraction with additional resistor 550 A AC 385 V DC Power Converter 10 V 385 V EE system 700 m. Ohms 395 V 4

Electrical Hazards V. Montabonnet - Safety during Hardware Commissioning 18 October 2007 o Burn due to short-circuit or opening of the load with current n n o Huge amount of energy stored in the superconducting magnets Main Dipole: 15. 7 Henrys – 11. 85 k. A = 1. 1 GJ BE CAREFUL !!! n n Zero Voltage doesn’t mean Zero Current Converter OFF but still current in the circuit Very long time constant: 4 hours for Main Dipole 11. 85 k. A AC -0. 2 V DC Power Converter Example: 1 Q converters after FASTPA, OFF 5

Preventions V. Montabonnet - Safety during Hardware Commissioning 18 October 2007 o Prevention against accidental contact n n n Signalization Grills added for the protection of the converter DC outputs Converter rack protection o Doors, panels added o Rack closed for the main dipole transformer 6

Voltage Range / UTE C 18 -510 Very Low Voltage V. Montabonnet - Safety during Hardware Commissioning 18 October 2007 TBTS, P, F BTA 0 50 V 500 V Most of converters DC side TBT 0 BTB Most of converters BTA AC side High Voltage Low Voltage 120 V BTA 750 V HTA HTB - Dipole - Warm Magnets HTA 1000 V 50 k. V - Dipole - Circuits with Extraction Energy Resistor - Warm Magnets 1500 V - Warm Magnets 75 k. V BTB TBTF: Très Basse Tension Fonctionnelle 7

Voltage Range / UTE C 18 -510 V. Montabonnet - Safety during Hardware Commissioning 18 October 2007 o Conclusion / UTE C 18 -510: n n BT domain even for DC output with low voltage (<10 V) Rules to apply o BT: Minimal distance from energized pieces >30 cm if not contain in IP 2 X envelope Envelope IP 2 X Definition Ø 12 mm Energized piece 8

LHC Safety Training o LHC Machine V. Montabonnet - Safety during Hardware Commissioning 18 October 2007 n n Not considered as a “Local Electrique” / UTE C 18 -510 Safety Training “Level 4” mandatory: http: //sir. cern. ch/ o BUT, not all the equipments are IP 2 X at the moment “ Keep away from electrical installations. Minimum distance is 50 cm. ” LHC machine safety training (level 4) RR Tunnel: DFB, Current Lead 9

Habilitation: for who ? V. Montabonnet - Safety during Hardware Commissioning 18 October 2007 No Electrical Work ? Yes Near energized electrical piece ? No • “Electrical Worker” for ümeasurement ümaintenance ü reparation ü modification BT <30 cm Yes Under the supervision of trained person ? No • “Chargé de Travaux” • “Chargé d’Intervention” • “Chargé de Consignation” Yes No Habilitation for Non Electrical Worker B 0 Habilitation for Electrical Worker B 1, B 2, BR, BC 10

Habilitation: Actors V. Montabonnet - Safety during Hardware Commissioning 18 October 2007 “Chargé de Travaux” “Chargé d’ Interventions” B 2 BR AC BC B 2 ü Supervise on the field - the work planned Ex: extension, modification - the “intervention” Ex: reparation, measurements BR “Chargé de Consignation” BC AT ü Ensure his own safety and the safety of people under his supervision ü Execute or get execute the consignation or part of it B 1 “Exécutant électricien” ü Execute electrical work ü Responsible for his own safety B 1 B 0 “Exécutant non électricien” B 0 ü Execute or supervise non electrical work ü Habilitation not mandatory if all electrical hazards have been removed 11

Consignation: Principle V. Montabonnet - Safety during Hardware Commissioning 18 October 2007 1ère étape de consignation 1) Separate the equipment from its electrical sources 2) Lock in open position the separation devices On the work area 2 nde étape de consignation 3) Identify the equipment 4) Check that the voltage is zero Earth and short-circuit (not mandatory in BT) 12

Consignation in 2 steps V. Montabonnet - Safety during Hardware Commissioning 18 October 2007 Request 1ère étape de consignation Consigne RPHE. UA 83. RQD. A 78 converter & Measure I=0 on DFBAO. 7 L 8 Chargé de Travaux Separate the converter from AC sources Chargé de Consignation C. C. [AB-PO for power converter] Lock in open position On the field AC 2 ième étape de consignation Identify the converter: To be sure that the work will be done on the correct equipment Chargé Travaux I=0 @ working point Chargé Travaux V=0, Earthing & Short-circuit Chargé Travaux Chargé Consignat. [AB-PO] Work can start under the responsability of the « Chargé de Travaux » under safe conditions n n Procedure: Première Etape de Consignation related to Power Converters http: //www. edms. cern. ch/853633 Procedure for any work of disconnection of warm parts of the superconductive circuits of LHC: Safety Aspects https: //edms. cern. ch/document/762293 13

Work Flowchart in LHC Context ChargéTravaux I HAVE A JOB TO ORGANIZE ON POTENTIALLY DANGEROUS INSTALLATION. I AM RESPONSIBLE FOR MY TEAM SAFETY V. Montabonnet - Safety during Hardware Commissioning 18 October 2007 01 ANALYSE HAZARDS: ELECTRICAL & OTHERS PLAN WITH POINT OWNER Mr Circuit E. I. C Pt Owner Where What ? C. T. REQUEST 1ère ETAPE DE CONSIGNATION AB/PO When ? ~~~~~~ ~~~~~ ~~~~~ ~~~…. 02 OK! C. T. © E. I. C Pt Owner C. T. IDs ©©© C. T. DELIVER ATTESTATION BACK TO C. T. © DO INTERVENTION IN SAFE CONDITIONS REMOVE MISE A LA TERRE AT/MEL GIVE BACK YELLOW FORM © AB/PO 05 ©©© AB/PO I=0 A 07 OK! Work! ©©© El. Ex. Non El. Ex. C. T. 08 AB/PO ©©© AB/PO V=0 V ©©© C. T. 04 CONSIGNE 1ère ETAPE VAT VAI MALT 03 © C. T. CONSIGNE 2ème ETAPE AT/MEL OK! AND / OR E. I. C ~~~~~~ ~~~~~ ~~~~~ ~~~…. 06 ©©© C. T. DECONSIGNE & INFORM EIC & P. OWNER 09 Job Done. ©©© ©© C. T. AB/PO 10 Done ! E. I. C ©©© ©© AB/PO Pt Owner JOB WAS DONE IN SAFE CONDITIONS. FOLLOW STEPS EASIER & SAFER 14 C. T.

Documents V. Montabonnet - Safety during Hardware Commissioning 18 October 2007 o Documents: n Attestation de 1ère Etape de Consignation n Autorisation de Travail AC AT 15

V. Montabonnet - Safety during Hardware Commissioning 18 October 2007 16