5.1.5 High Voltage Electrical Systems

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Electrical Shop Safe Work Procedure

5.1.5 High Voltage Electrical Systems

Original Approval Date: May, 2015
Date of Most Recent Review: February, 2020
Review Timeline: Three Years

Technical Reviewer: Manager, Electrical Shop:
Bruce McCurry

Management Endorsement: Director, Maintenance & Energy Services:
Steve Nyman

1. Purpose

All utility companies work under the same general guidelines with respect to substation isolation. The purpose of the procedure is for information only. These procedures are described under the Utility Work Protection Code. It is essential that when working under a utility protection permit that the supervisor and workers fully understand the rules and regulations that apply to the issue of utility protection permits.

2. Scope

When the need arises to de-energize any incoming power supply provided by Guelph Hydro to the site, the rules described in the Utility Work Protection Code must be followed.

3. Personal Protective Equipment Required

See 5.1.3 Personal Protective Equipment

4. Procedure

4.1 Protection Permits
The various levels of tagging described in the following text are for the use of Hydro Operating Authority and for the University staff for internal switching and tagging purposes. When tagging is required the rules and guidelines as described herein under Self Protection and/or Support Guarantee will apply only.

4,2 Self Protection Tag

4.2.1 The purpose of self-protection guidelines is to provide a procedure for a competent person to provide:

•  Work protection for self.

•  Work protection for one or more persons working as a team and supervised by the protection holder.

•   Work protection where there is only one point of isolation.

4.2.2 Self-protection may be employed in various situations:

•   For work or inspection on low voltage equipment and wiring in buildings, power plants  and substations.

•   For work by competent persons on any circuits, equipment or equipment in an emergency situation.

•   The person obtaining self-protection must be authorized by the Electrical Shop Manager or in his absence, the Manager, Electrical Design for the equipment to be taken out of      service and either direct or complete necessary switching operations.

•   The protection holder at all isolation points that could affect the circuit or apparatus equipment shall place secure locks and tags.

•    The self-protection tags shall be completed in detail prior to placement on isolation points

•    Where more than one work group is employing the same isolation points, each group should be responsible for placement and removal tags.

4.3. Supporting Guarantee

4.3.1. Work Permit

i)   The purpose of a Work Permit is to formalize protection for a work group or groups who require guaranteed isolation of a circuit or apparatus equipment that is controlled by Guelph Hydro.

ii)   In other than an unplanned or emergency situation, an Application for Work Protection form should be filled out in advance of requirement date and submitted to the controlling authority (Guelph Hydro).

iii)   Upon receipt the Guelph Hydro (operator) will prepare a switching operation for check, recheck and have the same checked by another senior operator, then initialed.

iv)   At the time the Work Permit is required, the operator at Guelph Hydro will complete the switching as indicated on the Order to Operate form and apply work permit tags to all isolating points as required and directed.

v)   Upon completion of same, the operator may issue a Work Permit, guaranteeing protection to a competent person at the specified work location.

vi)  This Work Permit guarantees isolation only and the person in charge at the work site would be required to cause the circuit or apparatus to be de-energized. (Check potential, apply grounds and lockout)

4.3.2. Responsibilities of the Permit Holder

i)    The protection of all staff working under their supervision.

ii)    Prior to work commencing, informing all staff under their supervision regarding isolation/de-energization of equipment and safeguards which have been applied to equipment involved and affected.

iii)   Authorizing work to be completed by staff under their supervision.

iv)   Ensuring lines and/or equipment have been isolated and de-energized.

v)    Informing each person under their supervision of the intention to surrender the Permit and advise them to stay clear of the equipment involved.

4.3.3.  Work and Test Permit

i)    The purpose of a work and test permit is to formalize protection for a work group that requires guaranteed isolation of a circuit or equipment. In addition, the work and test permit allows for authorized testing.

ii)    When test equipment is being used, the operator of the equipment is responsible for the protection of the other workers on the site. Before the “tester” makes any piece of the equipment live, he/she must inform all members of the work crew in the proximity of the equipment that it is “under test.”

iii)    The testing person must also establish the necessary barriers, signs and warning devices as required preventing access to the equipment under test.

iv)    Once the testing has been completed, it is the responsibility of the testing person to ensure the equipment is grounded and suitably discharged, verifying that contact will not result in shock or cause discharge of any electrical charge.

v)     Equipment not under test that is in close proximity to a piece of equipment under test must be grounded while the other piece of equipment is being tested. This will ensure no stray voltages are induced.

vi)    Note: It is of the utmost importance to observe the distinction between a “Work and Test Permit” and the “Work Permit”. With a Work Permit, under no circumstances may any of the apparatus be made alive. Conversely, with a Work and Test Permit, circuits or equipment may be energized (for test purposes only) by or at the request of the work and test permit holder or his/her agent, and these tests must be logged with the control authority and conducted with the approval of the system operator.

vii)    There are many situations that would indicate the need for a work and test permit.

Example:

i)    A work and test permit could be employed where a section of underground cable has faulted. The permit guaranteeing isolation from the system could be obtained from the Controlling Authority such as Guelph Hydro or the Electrical Department. Work and test permit tags will them be installed at all isolating points.

ii)   Test procedures (fault finding, high potential testing, etc.) could then be completed with the sanction of the control authority.

iii)   It is imperative that all persons in the work group understand that the work and test permit guarantees isolation from the system only and the circuit and equipment covered could become energized during specified prearranged test procedures.

5. Relevant Legislation

Occupational Health and Safety Act, 1990.

6. Related Policies, Procedures and Documents

N/A

Revision History