High Voltage Safety High Voltage Access W. Maes Department of - - PowerPoint PPT Presentation

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High Voltage Safety High Voltage Access W. Maes Department of - - PowerPoint PPT Presentation

High Voltage Safety High Voltage Access W. Maes Department of Marine Engineering Antwerp Maritime Academy HV, 2016 Willem Maes High Voltage Safety Outline Willem Maes High Voltage Safety The Use of the High Voltage Access procedure is


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High Voltage Safety

High Voltage Access

  • W. Maes

Department of Marine Engineering Antwerp Maritime Academy

HV, 2016

Willem Maes High Voltage Safety

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Outline

Willem Maes High Voltage Safety

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The Use of the High Voltage Access procedure is required in the following cases:

Any type of maintenance on high voltage equipment. Any type of repair to high voltage equipment. Any form of measurement on high voltage equipment.

Willem Maes High Voltage Safety

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Terminology

High Voltage DC > 1200V AC > 1000V

Willem Maes High Voltage Safety

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Terminology

LOTO Lock-out and Tag-out

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Terminology

LIVE Any electrical apparatus which is charged at a potential different from that of the mass.

Willem Maes High Voltage Safety

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Terminology

Safe Approach Distance The minimum safe approach distance that shall be maintained by an unauthorized person or any object from bare electrical apparatus and to day set at 3000mm

Willem Maes High Voltage Safety

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Terminology

Safe Working Distance The minimum approach distance for authorized personnel, for 6,6KV this is 1120mm.

Willem Maes High Voltage Safety

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Terminology

Competent Person (CP) A first electrician who has been found competent by the Chief engineer to have sufficient system knowledge of a particular system within the site/vessel/workshop.

Willem Maes High Voltage Safety

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Terminology

Permit to Work A formal written system used to control certain types of work that are potentially hazardous.

Willem Maes High Voltage Safety

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Terminology

Isolation Device A device used to remove and or physically isolate the energy of a source of energy from equipment, machinery, systems, plants to make them safe to work on.

Willem Maes High Voltage Safety

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Terminology

Isolated Device A device locked out and tagged of where appropriate with a personal danger lock and a personal danger tag by a person under supervision of a Competent Person according to the correct LOTO procedure.

Willem Maes High Voltage Safety

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Terminology

JHA Job Hazard Analysis.

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Terminology

Switching Program A document prepared by the appointed competent person which identifies the required steps for isolation.

Willem Maes High Voltage Safety

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Terminology

Installation Machinery Includes any equipment (mobile or fixed), appliance, apparatus, implement of tool and any component, fitting or accessory thereof, including all associated circuit breakers, valves, levers, isolators, etc

Willem Maes High Voltage Safety

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Terminology

Personal Danger Lock (PDL) Lock used to indicate that a person is working on the plant/

  • machinery. Each person involved in the job attaches a

personal danger lock and personal danger tag to each isolation device.

Willem Maes High Voltage Safety

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Terminology

(Red) Personal Danger Tag (PDT) Tag used to indicate that a person is working on the plant

  • r machinery. Each person involved in the job attaches a

personal danger tag to each of his personal danger locks. PDT not to be used for anything else.

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Terminology

RES Rapid earth switch: This switch is used to earth and short circuit a part of a switchboard.

Willem Maes High Voltage Safety

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Terminology

PPE Personal protective equipment.

Willem Maes High Voltage Safety

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STEP 1

Complete a JHA This can also be called a risk analysis.

Willem Maes High Voltage Safety

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STEP 2

Prepare a written switching sequence. Which breakers are to be separated from the switchboard? How and where measuring will take place? How and where additional earth will be placed? switching sequence is to be made up by the competent person in cooperation with an engineer deemed competent chief engineer. Is to be attached to this procedure. use up to date circuit diagrams.

Willem Maes High Voltage Safety

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STEP 3

Switch-off/ de-energize the respective part of the installation This can also be called a risk analysis.

Willem Maes High Voltage Safety

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STEP 4

Separate the respective part of the system from the live system. Also called Isolate. There must be a physical separation of the parts. A possibility is racking out a breaker. refer to the manufacturers instructions.

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STEP5

Measures against starting up. As described in the LOTO procedure.

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STEP 6

Earth the respective part of the switchboard. Use the RES

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STEP7

Verify if dead Stick voltage measuring device. 6.6kv =1120mm minimum. Test before measuring and after measuring. Until an installation is earthed it is considered live.

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STEP 8

Place additional earth if appropriate verify if dead use PPE

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STEP 9

Mark and shield live components. Neighboring parts can be live Ideally they are isolated also, but this is not always possible. Place barriers, isolating covers and clearly mark live parts. Take care with tools ladders etc. Remember 1120mm for 6.6KV

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STEP 10

Perform the job

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STEP 11

Remove the additional earth. First remove the phase connections. Remove the earth connection last. Ass soon as the additional earth is removed the installation is considered live.

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STEP 12

Remove the earth from the switchboard. Open the RES

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STEP 13

Remove measures against starting up. See LOTO

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STEP 14

Raise the separation, isolation. Meaning in most cases racking in the breaker.

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STEP 15

Re-energize the installation. Once the procedure is completed, the installation is declared operational and can be re-energized at any time it is deemed necessary.

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Non competent persons and persons not involved in the job

Warning sings must be placed in the vicinity of the work area, pointing out the dangers to non competent persons and persons not involved in the job. Remember safe approach distance for non competent persons = 3000mm.

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The workplace

Access routes around switching and distribution devices shall be free from obstacles and flammable materials. Sufficient access Enough room to work Adequate lighting Adequate escape routes falling, tripping etc. can also cause severe accidents near an electric installation.

Willem Maes High Voltage Safety