SUBSTATION DISTRIBUTION BOARDS OPSAF-12-007 AND NETWORK PILLARS … · 2018. 10. 26. · Issue 5 Geoff Ryan Section 8.7 – WL1.17 – additional precautions included for cable term

SUBSTATION DISTRIBUTION BOARDS

AND NETWORK PILLARS OPSAF-12-007

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© SP Power Systems Limited Page 1 of 25 LWM 3.1

1. SCOPE

This section of the Energy Networks Live Working Manual (LWM) details the procedures to be followed when Distribution Boards and Network Pillars are to be worked on Live. The procedure applies the principles established by the ScottishPower Safety Rules (Electrical and Mechanical) to achieve Safety from the System and in particular PSSI 12 - Low Voltage Apparatus.

2. ISSUE RECORD

This is a Reference document. The current version is held on the EN Document Library. It is your responsibility to ensure you work to the current version.

Issue Date Issue No Author Amendment Details

Feb 2004 Issue 4 W. Leggat Inclusion of New Procedures WL1.09. & WL 1.18 New format – paragraph numbers changed.

February 2007 (Available on Intranet with only limited circulation of Paper Copies)

Issue 5 Geoff Ryan Section 8.7 – WL1.17 – additional precautions included for cable term on shielded pattern LV board Addendum 1 added to provide procedure for recovery/erection of LV O/H Bars in indoor HV/LV substations.

September 2008 Issue 6 Geoff Ryan Addendum 1 from issue 5 now included within main document as new Section 11. Section 8.4 now provides for use of Approved temporary rigid screens. Section 8.6 updated Minor editorial changes.

July 2018 Issue 7 Kevin Rice Procedures WL1.04 and WL1.17 revised and combined into new procedure WL 1.41.

3. ISSUE AUTHORITY

Author Owner Issue Authority

Name: Kevin Rice Title: H&S Consultant

Name: Gary Evans Title: Operational Assurance Manager

Name: Ross Galbraith Title: Health and Safety Director

4. REVIEW

This is a Reference document which has a 5 year retention period after which a reminder will be issued to review and extend retention or archive.

DISTRIBUTION

This document is part of the Live Working Manual but does not have a maintained distribution list.



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5. CONTENTS

1. SCOPE ........................................................................................................................................... 1

2. ISSUE RECORD ............................................................................................................................ 1

3. ISSUE AUTHORITY ....................................................................................................................... 1

4. REVIEW ......................................................................................................................................... 1

DISTRIBUTION ....................................................................................................................................... 1

5. CONTENTS .................................................................................................................................... 2

6. DEFINITIONS ................................................................................................................................. 2

7. PROCEDURES AND PERSONAL PROTECTIVE EQUIPMENT FOR WORK ON OR NEAR LIVE APPARATUS ................................................................................................................................. 3

8. WORK WHICH MAY BE UNDERTAKEN ON APPARATUS CONTAINING LIVE EXPOSED LV CONDUCTORS, FOLLOWING ASSESSMENT BY AN AUTHORISED PERSON ............................... 3

8.1 PROCEDURE WL1.01 - CLEANING SUBSTATION DISTRIBUTION BOARDS AND NETWORK PILLARS . 3 8.2 PROCEDURE WL1.02 - DRESSING CONTACTS ON SUBSTATION BOARDS AND NETWORK PILLARS 3 8.3 PROCEDURE WL1.03 - REMOVING AND REPLACING CIRCUIT LABELS ......................................... 4 8.4 PROCEDURE WL1.41 - CHANGING BUSBAR AND FEEDER CONTACTS AND CHANGING OR

INSTALLING CABLE TERMINATIONS ON EITHER OPEN STYLE OR SHIELDED PATTERN LV BOARDS................. 5 8.5 PROCEDURE WL1.05 - TEMPORARY CONNECTION OF APPROVED TEST EQUIPMENT

/INSTRUMENTS .................................................................................................................................... 11 8.6 PROCEDURE WL1.09 - INSTALLATION OF LV MULTICORE CABLE TO CANNON VEAM STYLE

SNAPLOCK SYSTEM ............................................................................................................................. 12 8.7 PROCEDURE WL1.18 – MAINTENANCE OF LV AIR CIRCUIT BREAKERS ASSOCIATED WITH

SUBSTATION DISTRIBUTION BOARDS ..................................................................................................... 18 8.8 OTHER APPROVED TASKS ON LIVE APPARATUS ....................................................................... 19

9. WORK THAT MAY BE UNDERTAKEN ADJACENT TO APPARATUS CONTAINING LIVE EXPOSED LV CONDUCTORS FOLLOWING ASSESSMENT BY AN AUTHORISED PERSON. ..... 19

10. WORK WHICH MAY BE UNDERTAKEN ON OR ADJACENT TO APPARATUS CONTAINING LIVE EXPOSED LV CONDUCTORS FOLLOWING ASSESSMENT BY A SENIOR AUTHORISED PERSON ...................................................................................................................... 20

11. PROCEDURE WL1.07 - RECOVERY AND/OR ERECTION OF LV OVERHEAD BARS IN INDOOR HV/LV SUBSTATIONS. ........................................................................................................ 21

11.1 SCOPE .................................................................................................................................. 21 11.2 SAFETY DOCUMENTATION AND RISK ASSESSMENT. ................................................................. 21 11.3 PREFERRED METHOD OF WORK. ............................................................................................ 22 11.4 SHROUDING PROCEDURE FOR STANDARD OPEN TYPE FUSEBOARDS. ...................................... 23 11.5 AUTHORISATION ..................................................................................................................... 24

6. DEFINITIONS

Terms printed in bold type are as defined in the ScottishPower Safety Rules (Electrical and Mechanical) 4th Edition.



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7. PROCEDURES AND PERSONAL PROTECTIVE EQUIPMENT FOR WORK ON OR NEAR LIVE APPARATUS

All work on or so near Live exposed LV conductors that Danger may arise requires assessment before the commencement of work to ensure that Danger will not arise during the course of the work. This assessment shall be carried out by either the Authorised Person who is to undertake the work or, as specified in Section 10, by a Senior Authorised Person. In all cases, Apparatus shall be subjected to a routine inspection prior to the start of any work to ensure that Danger will not arise due to the condition of the Apparatus. Should this inspection reveal any significant deficiency in the Apparatus which could give rise to Danger, no attempt shall be made to work on the Apparatus whilst it is Live until a Senior Authorised Person has been consulted and assessed the situation. For any Live work/testing on substation LV distribution boards and pillars covered within this document, the following are the minimum Personal Protective Equipment requirements:

Approved FR coveralls shall be worn, fastened to the wrists, ankles and neck.

Approved light eye protection shall be worn.

These minimum PPE requirements may be increased, either by individual procedures within this document or as a result of the site specific risk assessment. In addition, Approved insulated tools shall be used and, where reasonably practicable work or testing shall be carried out whilst positioned on an Approved insulating mat.

8. WORK WHICH MAY BE UNDERTAKEN ON APPARATUS CONTAINING LIVE EXPOSED LV CONDUCTORS, FOLLOWING ASSESSMENT BY AN AUTHORISED PERSON

8.1 Procedure WL1.01 - Cleaning Substation Distribution Boards and Network Pillars

Cleaning may be carried out with the Apparatus Live subject to the following steps being taken:- Step 1 Check physical condition of the Apparatus:- all doors, covers, plates, conductors,

insulators and barriers to be secure and in good condition. Step 2 Check the Apparatus and its surrounding for any signs of distress/disturbance which

may have affected the insulation or security of the installation. Step 3 Use only Approved rubber gloves together with Approved insulation mats. Step 4 Use only Approved insulated tools and equipment (vacuum cleaner and sash brush). Step 5 Assess to ensure that during the course of the work Danger does not arise from a

flashover caused by loose dirt, dust, rust scale etc.

8.2 Procedure WL1.02 - Dressing Contacts on Substation Boards and Network Pillars

The use of metallic tools, e.g. files, for Live contact dressing is forbidden. Should the pitting be deep or extensive the dressing of contacts with the Apparatus Live is not appropriate and the work shall only be carried out following an assessment by a Senior Authorised Person. Lightly burnt or pitted contacts may be dressed with the Apparatus Live, subject to the following steps being taken: -



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Step 1 Check physical condition of the Apparatus: - all doors, covers, plates, conductors, insulators and barriers to be secure and in good condition.

Step 2 Check the Apparatus and it’s surrounding for any signs of distress/disturbance that

may have affected the insulation or security of the installation. Step 3 Check for the presence of foreign bodies, excessive dust or dirt, vermin, rust scale,

dampness or any other condition that may affect the insulation if disturbed. Step 4 Shroud adjacent Live or earthed metalwork to prevent inadvertent contact. Step 5 Use only Approved rubber gloves and insulation mats. Step 6 Use only Approved insulated tools (clean abrasive stones and insulated abrasive

tools), ensuring that no conducting track exists. Step 7 Assess to ensure that during the course of the work Danger does not arise from a

flashover caused by any debris (swarf, metal, dust etc). Step 8 Clean up any debris using the method described in 8.1 - Cleaning Substation

Distribution Boards and Network Pillars.

8.3 Procedure WL1.03 - Removing and Replacing Circuit Labels

In a few cases involving older Apparatus, circuit labels may have been fitted to Live conductors (busbars). No attempt shall be made to remove/replace such labels with the Apparatus Live. Circuit labels are fitted to Apparatus in many different positions using several different methods, e.g. screws, clips, adhesive, etc. They may be removed/replaced with the Apparatus Live subject to the following steps being taken: - Step 1 Check physical condition of the Apparatus: - all doors, covers, plates, conductors,

insulators and barriers to be secure and in good condition. Step 2 Check the Apparatus and it’s surrounding for any signs of distress/disturbance that


dampness or any other condition that may affect the insulation if disturbed. Step 4 Assess the position of the label and the method of fixing to ensure that

removal/replacement can be carried out without giving rise to Danger.

Pay particular attention to: - (i) the clearance from Live conductors. (ii) the length of any screws. (iii) the size and material of the label. (iv) the presence and nature of any backing plate which may be released. (v) the consequences of dropping or losing control of any of these items.

Step 5 Use only Approved rubber gloves and insulation mats. Step 6 Use only Approved insulated tools.



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8.4 Procedure WL1.41 - Changing Busbar and Feeder Contacts and changing or installing Cable Terminations on either open style or shielded pattern LV boards

8.4.1 Open style LV boards - general

An open style LV board is the type of board in which the bus bars, the bus bar contacts and feeder contacts are largely exposed at all times, with minimal shrouding or barriers in place to prevent contact with Live conductors. Typical open style LV boards

8.4.2 Shielded pattern LV boards - general

A shielded pattern LV board is one in which, under normal operating conditions, all Live parts are shrouded to a standard that prevents contact with Live conductors by the inadvertent insertion of a



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finger, but the shrouding may not prevent inadvertent insertion of a tool such as a screwdriver blade or an earth conductor strand; individual circuits are segregated by solid barriers. On some shielded pattern boards, the top of the board is completely open – before the start of work the board shall be examined to establish whether this is the case and where appropriate this shall be recorded on the risk assessment; care shall be taken to ensure that no attempt is made to place tools or other work equipment on top of the board. When dealing with a shielded pattern LV board, it is critical to take account of the fact that when work commences and any cover is removed from any part of the board, Live conductors may be exposed. When any cover is removed, close examination shall be carried out to determine whether Live conductors have been exposed; where this is the case, work shall not proceed until the exposed conductors have been Isolated. Typical shielded pattern LV boards

8.4.3 Preparatory work prior to the commencement of Live work

Before any work is carried out under this procedure on either an open style or a shielded pattern LV board, the Apparatus shall be examined to ensure that it is in good condition and not displaying any signs of deterioration or distress. All doors, covers, plates, conductors, insulators and barriers shall be examined. In the event that deterioration or distress is identified, Live work shall not proceed. At all stages of the work, an Approved insulated rubber mat shall be positioned in front of the LV board. Throughout the procedure, the minimum PPE to be worn is FR coveralls, safety footwear and light eye protection. Only cables that are not Live shall be terminated using this procedure.

8.4.4 Isolation requirements on open style LV boards

Wearing a full face visor and Approved rubber gloves, the following Switching shall be carried out to isolate the busbars of the LV board before any work is carried out under this procedure.

i. The LV transformer links and/or, the appropriate bus section isolating device.



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ii. The circuit being worked on, where there is a network cable already terminated; this isolation

shall not be achieved at the fuse position, but by creating a Point of Isolation at a position

away from the board.

iii. The circuit(s), including where necessary the transformer circuit, immediately adjacent to the

contact or cable termination to be worked on (see Note below); this isolation shall not be

achieved at the fuse or link position, but by creating Points of Isolation at positions away

from the board.

iv. The remaining circuits shall be Isolated at either the fuse position or at a position away from

the LV board.

The LV busbars to which the cable is to be connected, and adjacent circuits shall be proved not Live before the start of work.

Note: If the contact or cable termination to be worked on is bounded by a physical barrier (e.g. as on a Skeltag unit or by an Approved temporary or permanent rigid screening device) then, subject to the site-specific risk assessment, remote isolation of the circuit(s) on either side of the contact or cable termination may not be required. Before Approved temporary rigid screens are fitted, it shall be confirmed that they are the appropriate units for the type of board to be worked on and they shall be confirmed to be in a suitable condition.

Typical Skeltag LV board

8.4.5 Work on an open style LV board

Step 1 Check the Apparatus and its surroundings for any signs of distress/disturbance,

missing phase barriers, etc., that may have affected the insulation or security of the

installation.

Step 2 Check for the presence of foreign bodies, excessive dust or dirt, vermin, rust scale,

dampness or any other condition (e.g. noise) that may affect the insulation if

disturbed.



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Step 3 Determine the work zone, i.e. the zone into which personnel, tools and equipment are

likely to encroach during the course of the work. Remember that at times work may

be required from the front and rear of the Apparatus.

Step 4 Assess in a methodical manner the sequence of work involved to change the

contact(s) or cable termination or connect a new cable termination. Ensure that

during the course of the work Danger will not arise from: -

(i) the unexpected release of backing plates, screws or bolts;

(ii) the consequence of dropping or losing control of tools, backing plate, screws

or bolts, e.g. damage to cables in trenches under the point of work;

(iii) the use of parts that are not in accordance with the manufacturer's original

specification or not an Approved alternative;

(iv) the use of a modification that is not Approved.

Approved rubber gloves and full face visor shall be worn and Approved insulated tools shall be

used throughout the remainder of this procedure.

Step 5 Carry out the isolation described in section 8.4.4 above.

Step 6 Shroud all cable circuits on either side of the work zone, even if Approved temporary

rigid screens are being used. If appropriate shroud the front and/or rear of the

Apparatus. See diagram SP2022199 for typical application.

Step 7 Affix Danger Notices on fuseways/links on either side of the work zone and if

applicable at front and rear of the Apparatus.

Step 8 Carry out the work on the bus bar or feeder contacts or cable termination.

At completion of work:

Step 9 Check that the clearances between Live and/or Earthed metalwork have not been

compromised.

Step 10 Where applicable, check the cable connected under this procedure to ensure that the

insulation is sound by completing a visual inspection and insulation resistance and/or

continuity tests as per OPSAF-12-061 (LWM 2.6) section 8.2

Step 11 Remove the Danger Notices and shrouding applied in steps 7 and 6.

Step 12 With the exception of the circuit being worked on, remove all Points of Isolation

established in step 5 above.

Step 13 If a new cable has been connected and the cable is to be made Live then the

procedures in section 2.1 of the Live Working Manual (OPSAF-12-003 – Operation of

the LV System) of this manual shall be followed.



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Diagram based on SP2022199



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8.4.6 Isolation requirements on shielded pattern LV boards prior to Live work

On a shielded pattern board, the busbars shall be Isolated as in steps (i) and (iv) in section 8.4.4.

The LV busbars to which the cable is to be connected shall be proved not Live before the start of work.

Subject to a thorough site specific risk assessment, work may be carried out with the adjacent

circuit(s) Live. Where there is a network cable already terminated on the way to be worked on,

this circuit shall be Isolated at a position away from the board.

8.4.7 Work on shielded pattern LV boards

Due to the restricted working space it will only be possible to terminate 95mm2 and 185mm

2

cables with the adjacent ways Live and the adjacent covers in place. It may be possible to

terminate larger cables if one of the adjacent ways is Isolated (at a position away from the LV

board) so that the covers on one side can be removed to provide more working space.

A potential risk has been identified when preparing a new cable for termination. While

stripping/handling the neutral/earth wires it is possible for wires to make contact with Live

conductors if they are allowed to approach the open area at the bottom of the board or the slots

on the covers over adjacent Live fuseways. To minimise this risk the front of the board (excluding

the way on which work is to take place), down to the floor, shall be shrouded while

stripping/trimming the neutral/earth wires. The neutral/earth wires shall be cut approximately to

length and bunched before the cable is offered up to the LV board to determine exact trimming

length.

Step 1 Check the Apparatus and its surroundings for any signs of distress/disturbance that

may have affected the insulation or security of the installation.

Step 2 Check for the presence of foreign bodies, excessive dust or dirt, vermin, rust scale,

dampness or any other condition that may affect the insulation if disturbed.

Step 3 Determine the work zone, i.e. the zone into which personnel, tools and equipment are

likely to come during the course of the work. Remember that at times work may be

required from front and rear of the Apparatus.

Step 4 Assess in a methodical manner the sequence of work involved to change the

contact(s) or cable termination or connect a new cable termination. Ensure that

during the course of the work Danger will not arise from: -

(i) the unexpected release of backing plates, screws or bolts;

(ii) the consequence of dropping or losing control of tools, backing plate, screws

or bolts, e.g. damage to cables in trenches under the point of work;

(iii) the use of parts that are not in accordance with the manufacturer's original

specification or not an Approved alternative;

(iv) the use of a modification that is not Approved.

Step 5 Assess which phase covers etc. require to be removed in order that the jointing work may be carried out.



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Approved rubber gloves and full face visor shall be worn and Approved insulated tools shall be used throughout the remainder of this procedure. Step 6 Carry out the isolation detailed in section 8.4.6 above. Step 7 Remove the necessary cover(s), ensuring that no Live conductors have been

exposed. If Live conductors are exposed then these shall be Isolated before the work continues.

Step 8 Where a cable is being terminated, shroud the front of the LV board (excluding the

way on which work is to take place), down to the floor, before stripping/trimming the neutral earth wires. Bunch the neutral/earth wires and cut to approximate length before offering the cable up to the board for exact measurement.

Step 9 Carry out the work on the bus bar or feeder contacts or cable termination. At completion of work:

Step 10 Remove the shrouding applied in Step 8. Step 11 Check that the clearances between Live and/or Earthed metalwork have not been

compromised. Step 12 Where applicable, check the cable connected under this procedure is sound by

carrying out a visual inspection. Step 13 Refit any covers that were removed in step 7. Step 14 Carry out insulation resistance and continuity tests on any cable connected under this

procedure as per OPSAF-12-061 LWM 2.6 section 8.2 Step 15 Check the LV board to ensure that none of the covers etc. have been damaged

during the work and that all covers have been correctly replaced. Step 16 With the exception of the circuit being worked on, remove all Points of Isolation

established in step 6 above. Step 17 If a new cable has been connected and it is to be made Live then the procedures in

section LWM 2.1 (OPSAF-12-003 Operation of the LV System) of this manual shall be followed.

8.5 Procedure WL1.05 - Temporary Connection Of Approved Test Equipment /Instruments

Approved test equipment/instruments are those listed in LWM Section 8.1 or separately Approved for connection to the Live LV System. Approved test equipment/instruments may be connected to Live Apparatus subject to the following steps being taken: - Step 1 Check physical condition of the Apparatus: - all doors, covers, plates, conductors,

insulators and barriers to be secure and in good condition. Step 2 Check the Apparatus and it’s surrounding for any signs of distress/disturbance that

may have affected the insulation or security of the installation.



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Step 3 Check for the presence of foreign bodies, excessive dust or dirt, vermin, rust scale, dampness or any other condition that may affect the insulation if disturbed.

Step 4 Use only Approved insulated tools, rubber gloves and insulation mats, as

appropriate. Note: All OP and WL-1 authorisations allow Persons to use Approved test equipment appropriate to the activity e.g. test lamp, earth loop impedance instrument, phase rotation instrument, multimeter, “Fusemate”, fault location equipment, etc. WL1.05 is only required when the Person does not hold an appropriate OP or other WL-1 authorisation or if tools are required to fit the test equipment.

8.6 Procedure WL1.09 - Installation of LV multicore cable to Cannon Veam style Snaplock System

The Cannon Veam style Snaplock System is used to provide voltage sensing to automation systems installed in ground-mounted substations, and some instances also provides the auxiliary supply for the RTU. The Snaplock System utilises modified 82mm (JP) and 92mm (JS) fuse carriers to accommodate a shrouded outlet (see Drawing 2058644 at the end of this section). The current supplier, Ten47, also supply a 10m length of 4 mm2 3-core cable, suitably modified to facilitate ease of connection into the shrouded outlet point of the fuse-carrier. This cable is protected by a 32mm Type T 10A HBC in-line fuse (RS Code: 414-061) Only this fuse type shall be used. The proposed fuseway location of the modified fuse carrier should take into account the necessary cabling arrangements of the Snaplock System, giving due consideration to future fuse carrier withdrawal/insertion operations. For this reason, the modified fuse carrier should be located in the bottom (blue phase) right hand side fuseway. The manufacturer has also developed a G-clamp that may be used to facilitate connection to an open LV board (see Drawing 2058915 at the end of this section). All work on or so near Live exposed LV conductors that Danger may arise requires a Risk Assessment to be completed prior to commencement of the work to ensure that all hazards are reduced to an acceptable level during the course of the work. This Risk Assessment shall be carried out by the Authorised Person in control of the Working Party undertaking the work. Removal of a modified fuse carrier or a G-clamp may cause operation of the associated automation scheme, or loss of auxiliary supply to the RTU. The relevant Control Person must be advised prior to any such operation and the automation scheme switched off prior to the removal. Cabling to the Cannon Veam style Snaplock System may be carried out Live subject to the following steps being taken: - Step 1 Check physical condition of the Apparatus:- all doors, covers, plates, conductors,

insulators and barriers to be secure and in good condition. Step 2 Check the Apparatus and its surroundings for any signs of distress/disturbance that


dampness or any other condition that may affect the insulation if disturbed. Step 4 Identify the work zone, giving consideration to the preferred connection points for the

neutral and earth cores. No existing substation neutral and earth connection shall be broken to accommodate the connection of the neutral and earth cores.



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Consideration shall be given to the method of connection employed. Assessment shall be carried out giving particular attention to the neutral bar connection point given its likely close proximity to the blue phase conductors. The position of the LV neutral/earth link needs to be identified.

If the LV neutral/earth link is closed, then the neutral and earth cores shall be terminated on the respective sides of the link.

If the LV neutral/earth link is open, this installation shall also require an Isolation Transformer to be fitted to prevent a rise in HV earth potential being reflected into the LV network.

Step 5 Work shall be carried out in a methodical manner ensuring that during the course of

the work Danger will not arise from:

i The unexpected release of screws, washers, nuts or bolts. ii The consequence of dropping or losing control of tools, screws, washers, nuts

and bolts. Step 6 Assess to ensure that during the course of the work Danger does not arise from a

flashover caused by any debris (swarf, metal, dust etc). Step 7 Assess how the 3-core cable will be brought into the LV cabinet or pillar.

Consideration shall be given to how the 3-core cable shall be supported once installed.

Step 8 Use only Approved tools, rubber gloves and insulation mats. Step 9 Approved insulated tools should be inspected prior to use. Step 10 Examine Approved shrouding to ensure that there are no defects or damage that

could reduce its effectiveness. Step 11 Shroud adjacent Live or Earthed metalwork to prevent inadvertent contact.

Approved rubber gloves shall be used during the application and the removal of shrouding.

Step 12 Prior to drilling any entry hole, ensure that suitable clearance from any cable or

exposed Live or neutral conductor exists to allow the hole to be drilled safely. All drilling works shall be carried out below the height of the neutral bar.

Step 13 The 3-core cable shall be carefully passed from the inside of the pillar outwards.

Given that the pillar end of the 3-core cable is supplied pre-formed, the cable will not be able to be glanded in the conventional manner and, a suitable stuffing gland may be required. Care shall be taken to ensure that the neutral and earth cores of the cable do not come into contact with any Live Apparatus.

Step 14 Insulation resistance and continuity checks of the 3-core cable shall now be carried

out. Step 15 The earth and neutral cores of the 3-core cable shall now be connected. (In

accordance with Step 4). Step 16 The remote end of the cable shall now be terminated in the fused spur supplying the

Automation Remote Terminal Unit (RTU). Step 17 Remove the protective dustcap from the fuse carrier.



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Step 18 The phase conductor of the 3-core cable is supplied pre-terminated with a Snaplock

female connector and a Type T 10A in-line HBC fuse. This can now be inserted into the fuse carrier. (The phase conductor of the 3-core cable shall be positioned such that any future fuse carrier withdrawal/insertion operations will not be impeded). This action will energise the 3-core cable.

Should the 10A in-line fuse require to be replaced then the Snaplock female connector should first be removed from the modified fuse carrier.

When the insulated G-clamp is used, the phase conductor of the 3-core cable shall be connected to the G-clamp prior to the G-clamp being applied to the busbar. The G-clamp shall only be applied / removed from the busbar using the insulated spanner provided with the G-clamp. Should the 10A in-line fuse require to be replaced, the bayonet Snap Lock connector shall first be removed from the G-clamp.



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8.7 Procedure WL1.18 – Maintenance of LV Air Circuit Breakers associated with substation distribution boards

This procedure covers the maintenance of LV air circuit breakers in either substations containing a single LV board or two interconnected LV boards with the ACBs at opposite ends of the LV busbars. The procedure does not cover substations containing two interconnected LV boards with the ACBs adjacent to each other in the centre of the interconnected LV boards. Assessment All work on or so near Live exposed LV conductors that Danger may arise requires a Risk Assessment to be completed before the commencement of the work to ensure that all risks are reduced to an acceptable level during the course of the work. This Risk Assessment shall be carried out by the Authorised Person in control of the Working Party undertaking the work. In all cases, as part of the Risk Assessment, Apparatus shall be subjected to a routine inspection prior to the start of any work to ensure that Danger will not arise due to the condition of the Apparatus. Should this inspection reveal any significant defect in the condition of the Apparatus which could give rise to Danger, no attempt shall be made to work on the Apparatus whilst it is Live until a Senior Authorised Person (S-1) has been consulted and has completed an on-site Risk Assessment. Work may then proceed in accordance with Section 10 of this document. Where no significant defect has been identified, the Senior Authorised Person (SI-3 or above) in control of the work shall ensure that the work is carried out to the principles established by the ScottishPower Electrical and Mechanical Safety Rules to achieve Safety from the System, and in particular Power Systems Safety Instruction -12 Low Voltage Apparatus. In addition to the above, the following procedure shall apply:- 1. The Senior Authorised Person (SI-3 or above) shall determine a work zone around the LV

ACB i.e. the zone into which personnel, tools and equipment are likely to encroach during the course of the work.

2. The Senior Authorised Person (SI-3 or above) shall isolate all Live exposed LV conductors

within the work zone.

3. All work shall be carried out in accordance with Section 10 of this document.

4. The Authorised Person in control of the Working Party shall, immediately after the Isolation in (2), securely screen all adjacent exposed Live LV conductors (i.e. LV Board), using Approved screening (as described in OPSAF-12-024). Particular attention shall be paid to the side of the LV link and stalk adjacent to the work zone. The Senior Authorised Person (SI-3 or above) shall provide Personal Supervision to the Authorised Person whilst the Approved screening is being applied.

5. The Senior Authorised Person (SI-3 or above) shall ensure that, under his Personal

Supervision, any further exposed LV conductors outside, but in close proximity to, the work zone together with the screened conductors shall be identified and marked with Approved Danger Notices.

6. The Senior Authorised Person (SI-3 or above) shall ensure that all work is carried out under

the Permit for Work under OPSAF-11-021, or if the work is not taking place in conjunction with OPSAF-11-021 (PSMSP 2.10) a Limited Work Certificate shall be issued.



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7. The Authorised Person in control of the Working Party shall ensure that the work is carried out in accordance with section D5 of the Plant Maintenance Manual.

8. When the maintenance has been completed, prior to the re-energisation of the ACB, the

Senior Authorised Person (SI-3 or above) shall ensure that all tools, instruments and equipment have been removed from the work area. The Approved shrouding shall not be removed from the LV board until all work has been completed.

8.8 Other Approved Tasks on Live Apparatus

No work shall be undertaken Live unless temporary Approved written instructions detailing the safe method of work have been issued. The Authorised Person in charge of the work shall be fully conversant with the temporary Approved written instruction.

9. WORK THAT MAY BE UNDERTAKEN ADJACENT TO APPARATUS CONTAINING LIVE EXPOSED LV CONDUCTORS FOLLOWING ASSESSMENT BY AN AUTHORISED PERSON.

Any work in a substation with Live exposed LV conductors can give rise to Danger; even work not directly involving the Live LV Apparatus. Accordingly, when any work is carried out in such a substation an assessment shall be made by the Authorised Person in charge of the work to ensure that Danger will not arise during the course of the work due to accidental contact with Live exposed LV conductors. Unless the Authorised Person making the assessment is satisfied that no Danger can arise, work shall not commence until a Senior Authorised Person has been consulted and the procedures detailed in Section 10 below have been followed. Where necessary to prevent accidental contact, screening providing suitable mechanical protection shall be fitted under the supervision of the Authorised Person in charge of the work. Particular attention shall be paid to the following points: - The need to approach Live conductors. The size and nature of any material/tools being handled. The Danger of a fall from or collapse of any scaffold, ladder or access equipment.



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10. WORK WHICH MAY BE UNDERTAKEN ON OR ADJACENT TO APPARATUS CONTAINING LIVE EXPOSED LV CONDUCTORS FOLLOWING ASSESSMENT BY A SENIOR AUTHORISED PERSON

All work so near Live exposed LV conductors that Danger may arise other than that described in Sections 8 and 9 above, shall be assessed by a Senior Authorised Person prior to the commencement of the work and the following procedures shall apply: - The Senior Authorised Person (S-1 authorisation category) shall determine the work zone, i.e. the zone into which personnel, tools and equipment are likely to encroach during the course of the work. The Senior Authorised Person shall Isolate all Live exposed LV conductors within the work zone and unless the work zone is bounded by a fixed or Approved temporary physical barrier, e.g. as on a Skeltag unit, for a further 150 mm beyond the boundary of the work zone in all directions. All exposed Live LV conductors at any distance directly below the work zone shall be Isolated or adequately shrouded/screened. The Senior Authorised Person shall ensure that, under his Personal Supervision all exposed Live LV conductors within 1 metre of the boundary of the work zone are identified and marked with Danger Notices. If required, the Live LV conductors may be shrouded/screened using Approved materials as described in LWM 8.1 (OPSAF-12-024). All work carried out on the Apparatus shall be completed using Approved rubber gloves and/or insulation mats, and insulated tools. When working on Isolated conductors, Live working techniques shall be adopted to prevent Danger from the conductors becoming Live from inadvertent backfeed from private generation. The Senior Authorised Person shall issue a Limited Work Certificate, where necessary.



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11. PROCEDURE WL1.07 - RECOVERY AND/OR ERECTION OF LV OVERHEAD BARS IN INDOOR HV/LV SUBSTATIONS.

11.1 Scope

This section details the safe method of work for recovery and/or erection of LV overhead bars in indoor HV/LV substations.

11.2 Safety Documentation and Risk Assessment.

If the transformer or the LV fuseboard are connected to the System a Limited Work Certificate will be issued (unless a Permit for Work is to be issued for additional associated work). In all cases the transformer shall be Isolated at HV and the transformer LV Links shall be Isolated even when all the network fuses are removed. A Key Safe Key shall be issued with the Safety Document. The Senior Authorised Person issuing the Safety Document shall carry out a Risk Assessment of each situation and detail, on the Safety Document, the “precautions taken” and the “further precautions to be taken during the course of the work” to avoid System derived hazards. The Risk Assessment shall consider the following:

i. The physical condition of the Apparatus: - all conductors, insulators, and phase barriers to be secure and in good condition. Check for any signs of distress/disturbance that may have affected the integrity of insulation or security of the installation. Check also for the presence of foreign bodies, excessive dust or dirt, vermin, rust scale, dampness or any other condition that may affect the insulation if disturbed.

ii. The number of Persons required to handle the LV overhead bars during recovery or erection. While a minimum of two Persons will always be required, there may be situations where a third Person can assist by supporting each bar while the other two remove/replace the fixing bolts.

iii. Working at height and the need for stepladders. (Specification for stepladders can be found in Procurement Specification TSE-06-002).

iv. A safe place for storage of bars after recovery or when awaiting erection. In substations with more than one means of access, the route to be followed, while transporting the bars shall be agreed between the Senior Authorised Person and the Safety Document holder.

v. The availability of an adequate supply of Approved shrouding and insulated attaching clamps.

vi. The need for mobile generation and the route of generator cables through the work area. vii. Choice of appropriately experienced and suitably Authorised Persons. viii. The company policy for Live Work on the System (LWM 1.1, OPSAF-01-001) shall be

considered and an appropriate method of work as set out in Section 11.3 of this procedure shall be determined.



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11.3 Preferred Method of Work.

11.3.1 Enclosed Type LV Fuseboard.

On a modern enclosed type fuseboard the busbars and the incoming cables may be Live. If any fuses are not in position (e.g. normal open points) the exposed busbar and feeder stems must be fitted with Approved moulded-plastic stem shields (e.g. as supplied by the board manufacturer) or covered with Approved shrouding. The only other shrouding required will be to cover the open top with a suitable non-conductive board. Note: A suitable cover can be fabricated from two pieces of polycarbonate sheet or similar Approved material, one piece slightly smaller than the opening and the other slightly larger than the opening. When fixed together using plastic nuts and bolts the lid formed will sit securely in the opening with no risk of it being easily dislodged. Ensure the cover is clean and dry before each use.

11.3.2 Standard Open Type Fuseboards.

The Senior Authorised Person’s Risk Assessment shall consider the appropriate method of work in the following order: i LV Busbars and All cables not Live The preferred method of work is with the LV Board Busbars and all the incoming LV cables not Live. In this case all LV fuses will be removed and the incoming cables shrouded to guard against accidental re-energisation during work. ii LV Busbars and end cable not Live If method (i) is not reasonably practicable the LV Board Busbars and the incoming cable adjacent to the Transformer LV Links will be made not Live. In this case all LV fuses will be removed and the entire LV Board will be shrouded in accordance with the method set out in section 11.4 of this document. iii LV board only not Live If methods (i) or (ii) are not reasonably practicable the LV Board Busbars will be made not Live by removal of all the fuses and the entire LV Board will be shrouded in accordance with the method set out in section 11.4 of this document. iv All Live If methods (i), (ii), or (iii) are not reasonably practicable the LV Board Busbars may, subject to Risk Assessment, remain Live and the entire LV Board will be shrouded in accordance with the method set out in section 11.4 of this document.



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11.4 Shrouding Procedure for Standard Open Type Fuseboards.

The principle is to shroud all Live components with a minimum of 2 layers, and all Isolated components with a minimum of 1 layer, of Approved shrouding, each layer to be individually secured with Approved clamps. Whilst applying shrouding and replacing/removing the overhead bars, Approved Insulated gloves and a minimum of light eye protection shall be worn. 1. Cut “fingers” into two pieces of shrouding so that they can be interlocked through the gaps

between the base of the LV bars on the top of the LV Board and secure them together. See diagram 1 and photographs 1&2.

2. As appropriate wrap strips of rubber shrouding around the LV links or any busbar ends and

secure (Alternatively fit Approved moulded plastic cover caps when available). See Photograph 3.

3. Shroud over each fuseway and secure. See Photograph 4. 4. Place a strip of shrouding across the top of the LV board and secure. 5. Place a final sheet of shrouding over the entire LV board and secure. See Photograph 5. 6. Confirm that there is a minimum of 2 layers of shrouding over all Live components and a

minimum of one layer over any Isolated components. 7. Confirm that all shrouding is firmly secured and there are no gaps through which the end of

an overhead bar could accidentally fall. 8. Clear the work area of any tools, equipment, or materials that are not essential to the work in

hand. 9. When removing bars start with the bar furthest away from the Live Board and use insulated

tools to loosen the fixing bolts on one section of bar at a time. Replace bars in the opposite order.



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11.5 Authorisation

All Persons involved in work using this procedure shall hold at least one of the following authorisations: WL1.02 Dressing Contacts on Substation Boards and Network Pillars WL1.03 Removing and Replacing Circuit Labels WL1.04 Changing Busbar and Feeder Contacts and/or Cable Terminations. WL1.07 Recovery and or erection of LV overhead busbars in HV/LV substations WL1.18 Maintenance of LV Air Circuit Breakers associated with substation distribution boards WL1.41 Changing Busbar/Feeder Contacts and/or Installing or Removing a Cable Termination on Open or Shielded-Pattern LV Boards Generic Risk Assessment for Recovery or Erection of LV Overhead Bars on Live LV Boards.

Significant Hazards

Assessment of Risk

Severity Likelihood Outcome with no controls

Controls Outcome with controls

1 Contact by personnel with Live Conductors

Extremely Harmful

Likely Substantial Risk

SAPs Risk Assessment and Safety Document. Working Party’s On-Site Risk Assessment. Shrouding Procedure. Use of PPE – FR Coveralls, Eye protection, Insulated Gloves. Insulated tools. Briefing, supervision, and control of the Working Party by the Person in charge (Safety Document Recipient).

Acceptable Risk

2 Contact by conductive components with Live Conductors

Very Harmful

Likely Substantial Risk

Acceptable Risk

3 Falling From Height (only if step ladder used).

Harmful Unlikely Tolerable Risk

Choice of appropriate step ladder. Safety footwear

Acceptable Risk

4 Manual Handling Harmful Likely Tolerable Risk

Handling of only one bar at a time by a minimum of two Persons. Safety Footwear. Gloves.

Acceptable Risk

5 Slips, Trips, and Falls

Harmful Likely Moderate Risk

Clear Work Area. Agreed route and storage area.

Acceptable Risk



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Diagram 1 & Photographs 1 & 2: Cut “fingers” in two pieces of shrouding material to allow them to be interlocked through the gaps in the bars under the position where they are bolted to the LV Board. The loose “fingers” can either be cut off or just bent back out of the way. The width and number of the “fingers” will vary between different makes of board.

Diagram 1 Photograph 1 Photograph 2

Photograph 3. Ends of bars shrouded.

Photograph 4. Each fuseway shrouded.

Photograph 5. Second, overall,

layer of shrouding.

Documents

SUBSTATION DISTRIBUTION BOARDS OPSAF-12-007 AND NETWORK PILLARS … · 2018. 10. 26. · Issue 5 Geoff Ryan Section 8.7 – WL1.17 – additional precautions included for cable term