PEE STANDARD NUMBER: 110 · The nominal system voltage is either 66 kV or 132 kV as stated in the...

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REV – DRAFT 1 4 JANUARY 2001PEE STANDARD NO: 110

132 kV and 66 kV OVERHEAD POWER LINES FILED-F:\DATA\STANDARDS\PEE_STD\STD 110 – OVERHEAD LINES (132 kV and 66 kV)\Std 110.doc

NELSON MANDELA METROPOLITAN MUNICIPALITY

ELECTRICITY AND ENERGY BUSINESS UNIT

PEE STANDARD NUMBER: 110

________________

132 kV and 66 kV OVERHEAD POWER LINES

____________________________

REV – DRAFT 1 4 JANUARY 2001

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BLANK PAGE

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INDEX TO PEE STANDARD NUMBER 110


TABLE OF CONTENTS

PAGE 1. SCOPE 6

2. REFERENCES 6 2.1 Standards 2.2 NMMM Standards and Codes of Practice 2.3 Statutory Requirements

3. SERVICE CONDITIONS 7

4. CONTRACTOR’S CODE OF CONDUCT IN RESPECT OF THE ENVIRONMENT 7

5. QUALITY 8 5.1 General 5.2 Quality Assurance Provisions

6. TECHNICAL REQUIREMENTS 8 6.1 General 6.2 Tower Foundations 6.3 Tower Earthing 6.3.1 Tests to be carried out prior to Excavation for Foundations 6.3.2 Earthing Materials 6.3.3 Tower Ground Resistance

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PAGE 6.3.4 Galvanic Corrosion 6.3.4.1 Shielding Wire Insulation 6.3.4.2 Substation Terminal Tower 6.3.5 Earthing Method 6.3.6 Earth Conductor Connections 6.3.7 Tests to be performed at Completion of Each Tower 6.4 Steel Structures 6.5 Hillside Extension Leg Requirements 6.6 Galvanising 6.7 Painting 6.8 Standardisation and Marking of Structural Components 6.9 Bolts and Nuts 6.10 Conductor 6.10.1 All Aluminium Alloy Conductor 6.10.2 Greasing 6.11 Shield Wire / OPGW Protection Angle 6.12 Line and Earth Conductor Fittings 6.13 Insulators 6.14 Anti-Climbing Devices, Tower Leg Steps

7. INTERFERENCE WITH PROPERTY 13

8. COMPLETION OF WORK 14

9. CONTRACT PRICING 14 9.1 Tender Prices

10. DRAWINGS 14 10.1 General

11. MARKING, LABELLING AND SIGNS 15 11.1 Labels 11.2 Signs

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PAGE 11.3 Tower Numbering 11.3.1 CFP Numbering 11.3.2 Serial Numbers

12. DATA SHEETS 16

13. TEST CERTIFICATES 16

14. LITERATURE / DOCUMENTATION 16

15. SPARES AND SPECIAL TOOLS 16

16. TECHNICAL BACK-UP 16

17. INSTALLED USER BASE 16

AMENDMENTS An Amendment Sheet, giving a record of changes / updates to this Standard, is included as the last numbered page(s).

ANNEX 1 Painting of New Galvanised Steel Transmission Towers

ANNEX 2 Sealing of Bare Galvanised Steel Transmission Tower Structural Joints with Bitumen

during Erection

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PEE STANDARD NUMBER 110


1. SCOPE This Standard provides for the design, manufacture, erection and commissioning of 132 kV and 66 kV overhead power lines. 2. REFERENCES 2.1 Standards The overhead line and all components shall, unless otherwise specified, conform with the relevant Standards / Codes of Practice listed hereunder: - SABS 0160: 1989 : Code of Practice for General Procedures and Loadings to be adopted in

the design of buildings

SABS 044 : Welding

SABS 0100: 1992 : Structural Use of Concrete

SABS 0111 : Engineering Drawing – General Principles

SABS 0199: 1985 : The Design and Installation of an Earth Electrode

SABS 763: 1988 : Hot-Dip (galvanised) Zinc-Coatings (other than on continuously zinc-coated sheet and wire)

SABS CKS592: 1984 : Barbed Tape; Concertina

SABS 135 : Bolts and Nuts

SABS 0280 (NRS 041)

:

Code of Practice for Overhead Lines for Conditions Prevailing in South Africa (First Revision 1966)

IEC 493/1974 : Guide for Statistical Analysis of Ageing Tests Data

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BS 3242: 1970 : Aluminium Alloy Stranded Conductors for Overhead Power Transmission 2.2 NMMM Standards and Codes of Practice COP 10.1 : Common Rules

STD 134 : Composite String Insulators – 22 to 132 kV

STD 111 : Composite Overhead Ground Wire with Protective Optical Fibres

(OPGW) 2.3 Statutory Requirements All equipment, materials, methods of working and completed work offered against this Standard shall conform to the relevant requirements of the Occupational Health and Safety Act (Act 85 of 1993) as amended, and / or the Regulations framed under this Act. 3. SERVICE CONDITIONS The nominal system voltage is either 66 kV or 132 kV as stated in the Project Specification. The climatic, power system, insulation co-ordination and earthing detail shall be as outlined in PEE Code of Practice 10.1. 4. CONTRACTOR’S CODE OF CONDUCT IN RESPECT OF THE ENVIRONMENT Great care shall be taken during site and access preparation to ensure absolute minimum disturbance and damage to the vegetation. The following minimum steps shall be taken: -

The size of the work area shall be restricted to the minimum required for efficient and effective work;

A firm route shall be identified for access and clearly marked to avoid deviation there from.

Where vegetation is too big, it shall be chipped, but the soil, grass and smaller vegetation in the same area shall not be disturbed;

The work shall be properly planned in order to avoid unnecessary access to the place of

work;

No vegetation shall be removed other than the bare minimum required where foundation holes will be excavated;

Removed plant material shall be retained for later use in the re-vegetation and landscaping

of the areas;

All construction equipment shall be in good working order, especially with respect to oil, fuel, hydraulic and similar leaks;

No treatment of contaminated soils (e.g. bio-remediation) shall be allowed prior to obtaining

approval from the regional conservation authority;

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Excavated material shall be placed such as to have minimum impact on vegetation. Plan for worst case, i.e. heavy rainfall and run-off events or high winds;

Use separate storage for top and subsoil horizons, replacing them in the same order after

planting the tower feet where practically possible;

Spoil shall be removed from the site as soon as it is practically possible and disposed of at a registered waste disposal site;

All disturbed sites shall be re-vegetated and rehabilitated immediately after construction to

limit the exposure of the disturbed areas to wind and water erosion;

Protect exposed soils with coarse granular materials, mulches or straw where the above is not possible;

All litter shall be removed from the site at completion.

5. QUALITY 5.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout. 5.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract. 6. TECHNICAL REQUIREMENTS 6.1 General SABS 0160, SABS 0280, the Occupational Health and Safety Act (OHS Act) and PEE Code of Practice 10.1 (Clauses 1 and 8), all contain design parameters, which are in conflict with each other. For the purpose of this contract the most severe of the parameters referred to by these three documents shall apply. The Project Manager will not seek exemption from OHS Act in terms of SABS 0280 and the design shall meet all requirements of the Act. 6.2 Tower Foundations For quotation purposes, tower foundations shall be designed assuming the soil bearing pressure listed in the Project Specification.

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The successful tenderer must satisfy himself/herself regarding ground conditions at each tower position before finalising the design. He might require the service of a Geo-technical Engineer to carry out a soils investigation. Additional payment shall be allowed for soil conditions varying from the conditions stated in the Project Specification, providing that details of the tender design and the new design be made available to the Project Manager. Tenderers must submit all foundation and reinforcement details and concrete mix as part of the tender submission. All concrete, materials and workmanship shall be in accordance with SABS 0100-2: 1992 – Structural Use of Concrete. If part of the are where the line should be constructed is subject to periodic tidal flooding and / or has a high water table, the salinity of the water must be established to determine the concrete class and if protection of the reinforcement is required (refer to Clause 4.3.2). The portion of the tower legs to a height of not less than 300mm above finished ground level must be embedded in concrete. The top of the concrete shall have a slight taper (foundations shall be capped) for draining purposes. A UV resistant bitumen base sealer to be approved by the Employer shall seal off the tower leg entries into the concrete. Bond between the galvanised stub anchors and the concrete shall not solely be relied upon to transmit loads to the foundations. In addition, a mechanical bond shall be employed, viz. welding on a cleat or bar to the embedded end of the stub anchor. 6.3 Tower Earthing 6.3.1 Tests to be carried out prior to Excavation for Foundations A soil resistivity survey shall be carried out at each tower position before excavation for the foundations start. 6.3.2 Earthing Materials The earthing conductor shall be a 50mm x 6mm galvanised steel strip. Where earth rods will be used, these shall be designed and installed to SABS 0199. Stranded 70mm2 Cu conductor shall be used to connect earth rods together and to the tower. 6.3.3 Tower Ground Resistance The ground resistance of any tower shall be less than 10. 6.3.4 Galvanic Corrosion 6.3.4.1 Shielding Wire Insulation To prevent galvanic corrosion, the shield wires shall be insulated from the towers in the following scenarios: -

The last five towers on the substation end of the line including the termination tower;

Where the transmission line runs parallel to underground ferrous pipelines and / or railway tracks, inclusive of a distance of 800m from the point of deviation from the parallel run;

For 800m on either side of a railway track or a ferrous pipeline crossing.

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6.3.4.2 Substation Terminal Tower The two legs of the termination tower nearest to the substation shall be connected to the main substation earth mat using 70mm2 stranded copper conductor. Each tower leg shall have its own earth conductor. 6.3.5 Earthing Method 6.3.5.1 After foundations have been cast, a 50 x 6mm galvanised steel strap shall be taken down

each tower leg along the outside corner of each foundation. At the bottom of the foundation, the strap shall be wrapped around the foundation once and brought up the same route to the starting point.

6.3.5.2 Should the earth resistance obtained by 6.3.5.1 be higher than required, trench earths shall

be run out from two of the tower’s legs, which are diagonally across from each other. The depths and lengths shall depend on the soil resistivity survey to be done prior to excavating for the foundations.

6.3.5.3 Quotations (provisional) for 6.3.5.2 shall be based on a trench depth of 800mm and a length

of 15m each. 6.3.5.4 Further trench earths should be run from the remaining two legs, should the ground

resistance be too high following implementation of 6.3.5.3. 6.3.5.5 Should the soil resistivity survey display conditions more suitable for earth rods, suitable

earth rods could replace the trench earths in 6.3.5.2 and 6.3.5.4. Quotations should allow for 3 x 1,8m rods coupled to each other and driven to 500mm below natural ground level at two of the tower’s legs.

6.3.5.6 The tender price shall only allow for earthing in terms of 6.3.5.1. Should further earthing be

required, additional payment in accordance with the provisional amounts shall be allowed. 6.3.6 Earth Conductor Connections The earthing conductors shall be bolted to the tower legs. Where stranded copper is used, it shall be crimped in suitable bi-metal lugs and bolted to the tower legs. The copper conductor shall be CADWELDED to earth rods and to main substation earth mats where applicable. 6.3.7 Tests to be performed at Completion of Each Tower The following tests shall be done by contractors/sub-contractors with sufficient previous experience of similar tests: -

A ground resistance test in accordance with SABS 0199;

The step and touch voltages in accordance with IEEE 81.2: 1991. Tenderers shall quote in their tender submissions: -

The name of the sub-contractor who will carry out after-installation earthing tests;

The IEEE 81.2 method / instrumentation proposed to use for the step and touch voltage measurements.

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6.4 Steel Structures All steel used in the manufacture of the towers and tee-off arrangements shall conform to SABS 0162 Structural Use of Steel (all three sections). The grade of steel used shall be clearly indicated on the tender drawings. Rolled steel sections must have a minimum thickness of 5mm unless otherwise specified in the Project Specification. All steel used shall be free of blisters, scales, lamination and other defects. Tenderers’ attention is drawn to Clause 5.12.3, which would require a tower design capable of carrying suspended shielding conductor and OPGW. Overlapping steel sections shall be sealed off at bolt down positions by a UV resistant bitumen base sealer to be approved by the Employer. 6.5 Hillside Extension Leg Requirements Where towers on slopes need hillside extension legs, tenderers shall include prices for these with the tender. 6.6 Galvanising All the mild steel tower and line components including nuts, bolts and washers shall be hot-dip galvanised (heavy-duty requirements) in accordance with SABS 763. Galvanising shall be carried out in a professional way and sharp points where wrap-around wire has been used or as a result of dripping are unacceptable. The cost of re-galvanising any component, which does not comply with the requirements of the above Code of Practice shall be for the contractor’s account. 6.7 Painting Steel structures shall not be painted. 6.8 Standardisation and Marking of Structural Components All nominally identical structural members shall be interchangeable. All parts shall be carefully cut and holes accurately located so that when the members are in position, the holes will be truly opposite each other before being bolted up. Drifting of holes will not be allowed. No bolt hole shall be more than 2,0mm larger than the corresponding bolt diameter. Before leaving the manufacturer’s works, all members shall be stamped or marked in approved positions with distinguishing numbers and / or letters on approved drawings or material lists to be submitted by the successful tenderer. The erection marks shall be stamped before galvanising and shall be clearly legible after galvanising. 6.9 Bolts and Nuts Bolts and nuts shall be manufactured and supplied to SABS 135. All bolts must be supplied complete with washers, nuts and lock nuts.

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Bolts such as those for attaching the plates and brackets that support insulator strain sets shall have either self-locking nuts or lock nuts. In order to prevent theft of individual structural members, all nuts must be tack-welded to the bolt threads up to the height of the lowest cross-arm. Stainless steel welding rods must be used for this purpose. Welding positions shall be treated generously with cold galvanising. Final tightening of the nuts shall be done by torque wrench. 6.10 Conductor Unless otherwise specified in the Project Specification, phase conductors and earth wires shall be of all aluminium alloy conductor. Where OPGW is specified in the Project Specification, it will be supplied and installed to PEE Standard No 111. Tenderers must note that the conductor is to be used in a harsh coastal environment close to the sea. It is imperative that every effort be made to reduce corrosion in service to a minimum. 6.10.1 All Aluminium Alloy Conductor The conductor shall be in accordance with BS 3242. The conductor strands shall be drawn from solution treated (high temperature heat-soaked and quenched) redraw wire. The drawn conductor shall be artificially aged by annealing for several hours at a suitable low temperature to improve the corrosion resistance and increase conductivity as recommended by the suppliers of the redraw wire. 6.10.2 Greasing The conductors shall be greased using a process, which ensures that all layers are greased and all interstices filled. The grease shall have suitable properties of pseudoplasticity, thixotropy and syneresis. The grease shall be CABLE GUARD or approved equal. 6.11 Shield Wire / OPGW Protection Angle The earth wire / OPGW protection angle shall comply with SABS 003. 6.12 Line and Earth Conductor Fittings The tension and suspension insulator long rod units for the line conductors are to be secured to the cross-arms by means of galvanised tower shackles. All phase conductor insulator suspension attachment clamping arrangements shall be of the neoprene insert “Armour-Grip” suspension unit type with preformed aluminium alloy armour rods with “parrot bill” ends suitable for the line size as made by Preformed Line Products SA (Pty) Ltd or approved equal. The shielding wire(s) shall be suspended by means of suspension attachment units. Insulators shall be used where called for by Clause 5.3.4. All phase conductors and shielding wires (excluding OPGW) shall be made off at strainer and terminal towers by means of compression dead-end make-off assemblies as offered by ABB Feralin or CCL Bi-Metal Connector Manufacturers or approved equal.

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Composite long rod insulators shall not be fitted with arcing horns, except where called for by Clause 5.11.9. A sag adjuster shall be fitted between the insulator string and tower on all phase conductors at all strain and termination points. This shall be one of the Quadrant Plate Type as made by ABB Feralin or approved equal. Any shackles, pins or other line fittings, etc, not specifically mentioned shall be allowed for in the tender. Vibration dampers shall be of the solid polyvinyl chloride preformed spiral type and there shall be one fitted at both ends of each phase conductor span and earth wire span. The vibration dampers shall be as made by Preformed Line Products SA (Pty) Ltd or approved equal. To comply with the Electrical Machinery Regulations of OHS Act, Clause 20(e), the combination of Armour-Grip Suspension units and galvanised mild steel arcing horns shall be used. The arcing horns shall be double-point at suspension locations and single-point at strainer locations. Notwithstanding what is called for in PEE Standard No. 133, tongue-tongue end will be acceptable where arcing horns are installed. 6.13 Insulators 6.13.1 Phase Insulators Insulators shall be supplied in accordance with PEE Standard No. 133. 6.13.2 Earth Wire OPGW Insulators The purpose of the insulators is to prevent galvanic corrosion. The insulators shall be fitted with arcing horns. Tenderers shall submit information on both suspension and strain insulators including detail on insulation voltage, arcing horn gaps, fittings, material, etc. The successful tenderer shall submit samples for approval. 6.14 Anti-Climbing Devices, Tower Leg Steps All structures shall be fitted with barbed-tape anti-climbing devices at a height of not less than 3m from ground level. The barbed-tape shall be manufactured in accordance with SABS CKS592 of 1984. The barbed-tape shall be of the “concertina” coil form as offered by Cape Gate or approved equal. The coil diameter on the inside of the tower shall be 730mm while the outside coil shall be 980mm diameter. The barbed-tape and dovetail clips shall be heavy-duty galvanised to SABS 763. Tower leg steps shall be fitted up two opposite sides of the tower. The lowest steps shall be 3m above ground level. 7. INTERFERENCE WITH PROPERTY The tenderer shall conduct his work such that it will minimise interference with traffic and essential services and shall provide for and comply with any relevant ordinance. He shall liase with all relevant authorities before interfering with any traffic or other services.

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The contractor shall indemnify the Council against all actions and damage or proceedings, which may be brought or taken against the Council in respect of damage caused to any highway, road or street, or any person or property thereon, due to the conveyance, whether by ordinary or extraordinary traffic, by the contractor of any plant, materials, tools or tackle required for the works to, or from, the site during the period of contract. The contractor or his sub-contractor, representative, servants or workmen shall not in any way encroach on or interfere with private property, or property of the Council, or with any existing transmission lines, except with written approval. Where the power line servitude traverses private property, the contractor shall cause minimum possible disturbance to property and shall use his best endeavours to avoid friction with the property owners. Access routes will be pointed out to the contractor’s local agent and the contractor shall obtain access to the line route by means of these routes only. Funds required for the construction of additional access roads should be included in the tendered price. As each of the contract works is completed, the contractor shall, at his own expense, remove all rubbish, surplus excavated materials and debris, unused materials, temporary erections and plant. The contractor shall execute such works so as to ensure that the site of the contract works and the adjoining ground shall be left clear, all subject to approval. All litter and debris produced by the tenderer shall be collected and taken back to the construction camp for disposal at the end of each day’s work. 8. COMPLETION OF WORK As each part of the contract work is carried out, the City Electrical Engineer or his representative shall approve it and all work will be carried out to his satisfaction. 9. CONTRACT PRICING 9.1 Tender Prices In order that tenderers will all quote on the same basis if the price is not firm, tender prices are to be based on the applicable SEIFSA contract price adjustment formula and base prices for the month prior to tender closing date. All base prices for materials and labour shall be stated, together with the adjustment formula. The price quoted is to include all delivery charges and other costs or dues that may become payable whilst the equipment is in transit from the place of manufacture to its position at the site as defined. 10. DRAWINGS 10.1 General Drawings shall be done in AutoCAD Version 14 or later and shall be supplied in both software and hardware format. All drawings shall be to scale and fully detailed. All important dimensions shall be given. Drawings submitted for approval shall be in triplicate and the contractor shall supply any further copies upon request. The original drawings shall be prepared in such a manner that they comply fully with the requirements of SABS 0111 Part 1: Engineering Drawing – General Principles, in order that acceptable microfilm versions can be made from them.

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11. MARKING, LABELLING AND SIGNS 11.1 Labels All apparatus, where necessary / required, is to be clearly and indelibly labelled to ensure correct operation and safety both to the plant and to the operators. Labels not exposed to the weather shall be of engraved laminated Traffolyte or equal approved black material having white lettering or, in the case of danger notices, it shall have red lettering on a white background. Labels and diagram plates exposed to the weather shall be of stainless steel or equivalent with all information permanently applied by etching, engraving or stamping. All lettering shall be of ample size and clearly legible and all labels shall be attached by means of either screws, bolts and nuts or pop rivets. Labels and diagram plates should be offset from the apparatus to which they are fixed so that water may not collect between the two surfaces. 11.2 Signs Durable, heavy-duty, corrosion-resistant danger signs in English, Afrikaans and Xhosa are to be provided on each tower and gantry. These signs are to comply with the requirements of the Occupational Health and Safety Act, No 85 of 1993, as amended, and / or the Regulations framed there under. 11.3 Tower Numbering All towers and gantries are to be numbered by the contractor. Two types of numbers shall number towers, i.e. tower serial numbers and circuit fixing point (CFP) numbers. 11.3.1 CFP Numbering CFP numbering must be applied to all four legs, at approximately 2 metres above ground level, below the anti-climbing guard. Each circuit of the double line will have its own numbering systems. Each tower will therefore have two groups of 2 numbers, the numbers in each group being identical. Letters and numerals must be 80mm in height. After thorough de-greasing of the number positions, a background colour of Canary Yellow shall be painted using approved enamel paint to SABS Specification 630. The paint thickness shall be to the paint manufacturer’s specification. Letters and numerals shall be done in black enamel paint complying with SABS Specification 630. Characters shall be straight and evenly spaced. The paint thickness shall be to the paint manufacturer’s specification. Each number could consist of a maximum of 25 characters. The average number of characters per CFP number shall be 16. 11.3.2 Serial Numbers Serial numbers shall be supplied complete to the contractor who shall install the same at a height of approximately 1.8 metres above ground level.

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12. DATA SHEETS The contractor will be required to complete data sheets identical to the one included in Annex F in respect of each tower. Blank data sheets will be provided to the contractor. 13. TEST CERTIFICATES Two certified copies of test certificates must be submitted with the tender to show that the towers offered have passed tower tests in accordance with the relevant South African, IEC and British Standards specified and to verify that the design is satisfactory for the specified duty. A “Letter of Compliance” shall be obtained from the galvanising firm(s) stating that all hot-dip zinc coatings comply with the requirements of SABS 763 (Heavy-Duty). Two certified copies of test certificates shall be submitted to the City Electrical Engineer for each length of conductor, as manufactured. Any tests proving that the conductor parameters fall outside the specified limits shall result in rejection of the whole manufactured length. A “Letter of Compliance” shall be obtained from the AAAC conductor manufacturer(s) stating that all conductors supplied has been greased in accordance with Clause 4.10.2 of this Standard. The costs of all tests, certificates and “Letters of Compliance” required must be included in the tendered price and detailed in the tenderer’s covering letter. 14. LITERATURE / DOCUMENTATION The tender offer must be accompanied by descriptive literature and drawings showing dimensions. 15. SPARES AND SPECIAL TOOLS Tenderers are to quote for any spares and special tools, which are considered necessary for maintaining the equipment in service. If bolts or nuts are so placed as to be inaccessible with ordinary spanners, suitable special spanners shall be supplied. 16. TECHNICAL BACK-UP Details of the technical back-up / repair facilities available in South Africa are to be provided. 17. INSTALLED USER BASE Tenderers must state how long each type of tower offered has been in service, along with the names and addresses of at least two South African users who can be contacted for comment on the performance.

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PEE STANDARD: NUMBER 110


AMENDMENT SHEET [LAST NUMBERED PAGE(S) OF STANDARD]

REV NO.

DETAILS

AUTHOR

DATE OF REVISION / ISSUE

Page 1 of 1 (Annex A)

REV – DRAFT 1 24 JANUARY 2001 PEE STANDARD NO: 111 OPTICAL GROUND WIRE

FILED-F:\DATA\STANDARDS\PEE_STD\STD 111 – OPTICAL GROUND WIRE (OPGW)\Std 111 – Annex A.doc

ANNEX A

REQUIRED FORMAT FOR PRESENTATION OF TEST RESULTS (EXAMPLE – REFER CLAUSE 3.6.5)

Site : Athene Substation Cable Number : Hillside F/0 1 End 1 : Athene Substation Carrier Room End 2 : Hillside Substation Carrier Room

Tested From

Total

Length

Joint 1

Distance

Joint 2

Distance

Joint 3

Distance

Joint 4

Distance

Joint 5

Distance

Joint 6

Distance

Joint 7

Distance

End 1

7662 2 145 2711

3940 5971 7579 7659

End 2

7662 7660 7517 4951

4172 1691 83 3

Fibre

Number

Tested From

Total Loss

Joint 1 Loss

Joint 2 Loss

Joint 3 Loss

Joint 4 Loss

Joint 5 Loss

Joint 6 Loss

Joint 7 Loss

Mean Loss

Worst

Average 1 End 1 13,64 0,06 0,12 0,08 0,12 0,09 0,10 0,07

0,09

0,13 1 End 2 13,66 0,07 0,13 0,09 0,12 0,08 0,12 0,05 1 Average 13,65 0,07 0,13 0,09 0,12 0,09 0,11 0,06 2 End 1 13,67 0,05 0,11 0,10 0,12 0,07 0,15 0,07

0,10

0,14 2 End 2 13,68 0,09 0,13 0,09 0,12 0,08 0,12 0,05 2 Average 13,68 0,07 0,12 0,10 0,12 0,08 0,14 0,06 3 End 1 13,72 0,05 0,14 0,10 0,12 0,09 0,15 0,07

0,10

0,14 3 End 2 13,63 0,04 0,13 0,09 0,12 0,08 0,12 0,05 3 Average 13,68 0,05 0,14 0,10 0,12 0,09 0,14 0,06 4 End 1 13,75 0,08 0,14 0,10 0,12 0,09 0,15 0,07

0,10

0,14 4 End 2 13,68 0,07 0,13 0,09 0,12 0,08 0,12 0,05 4 Average 13,71 0,08 0,14 0,10 0,12 0,09 0,14 0,06

Page 1 of 13

REV – DRAFT 1 24 JANUARY 2001PEE STANDARD NO: 111 OPTICAL GROUND WIRE

FILED-F:\DATA\STANDARDS\PEE_STD\STD 111 – OPTICAL GROUND WIRE (OPGW)\Std 111.doc




________________

COMPOSITE OVERHEAD GROUND WIRE

(OPGW)

____________________________


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BLANK PAGE

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COMPOSITE OVERHEAD GROUND WIRE (OPGW)

TABLE OF CONTENTS

PAGE 1. SCOPE 5 1.1 Manufacture 1.2 Erection and Commissioning

2. REFERENCES 5 2.1 Standards 2.2 NMMM Standards and Codes of Practice 2.3 Statutory Requirements

3. TECHNICAL REQUIREMENTS 6 3.1 General 3.2 Optical Fibre Properties 3.3 Optical Fibre Carrier (Central Protection Unit / Tube) 3.4 Armour (Outing Earthing Conductor Stranding) 3.5 Information to be supplied by the Manufacturer 3.6 Installation and Commissioning 3.6.1 Jointing

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PAGE 3.6.2 Terminations 3.6.2.1 General 3.6.2.2 Underground Optical Fibre Cable 3.6.3 Joints, Clamps and Distribution / Joint Boxes 3.6.4 Stringing 3.6.5 Fibre Optic Testing Procedure

4. TRAINING 10


6. DRAWINGS 11 6.1 General

7. INSTRUCTION / MAINTENANCE MANUALS 11

8. MARKING AND LABELLING 11

9. TESTS 12 9.1 Type Test Certificates 9.2 Routine Test Certificates

10. TENDER LITERATRE / DOCUMENTATION 12

11. TECHNICAL BACK-UP 12

12. SPARES AND SPECIAL TOOLS 12

13. INSTALLED USER BASE 12


ANNEX A Presentation of Optical Fibre Test Results

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1. SCOPE This Standard provides for the following: - 1.1 Manufacture The essential optical, electrical and mechanical design characteristics, acceptance criteria and test requirements of all aluminium alloy armoured optical fibre core overhead ground wire (OPGW) for use with Overhead Power Transmission Lines. 1.2 Erection and Commissioning The supply, delivery, off-loading, installation, commissioning and final testing of the OPGW. 2. REFERENCES 2.1 Standards The optical protective ground wire (OPGW) shall, unless otherwise specified, be designed, manufactured, works tested, erected, commissioned and tested on site in accordance with the relevant requirements of the Standards / Codes of Practice listed hereunder: - IEC 793-1 : Optical Fibre

Part 1: Generic Specifications

IEC 793-2 : Optical Fibre Part 2: Product Specifications

IEC 794-1 :

Optical Fibre Part 1: Generic Specifications

IEC 794-2 : Optical Fibre Part 2: Product Specifications

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IEC 889 : Hard-Drawn Aluminium Wire for Overhead Line Conductors

IEC 1232 : Aluminium Clad Steel Wire for Electrical Purposes

ISO 9000 : Quality Systems

BS 3242: 1970 : Aluminium Alloy Stranded Conductors for Overhead Power Transmission

ITU-T Recommendation G.652

: “Characteristics of a Single Mode Optical Fibre Cable”

2.2 NMMM Standards and Codes of Practice This Standard is to be read in conjunction with and as part of the following: - NMMM Std No: 110 : 132 kV and 66 kV Overhead Power Lines 2.3 Statutory Requirements All equipment, materials, methods of working and completed word offered against this Standard shall conform to the relevant requirements of the Occupational Health and Safety Act (Act 85 of 1993) as amended, and / or the Regulations framed there under. 3. TECHNICAL REQUIREMENTS 3.1 General 3.1.1 The Optical Fibre Ground Wire (OPGW) shall contain the optical fibres and the necessary

protective outer layer to prevent damage to the fibres due to mechanical elongation, bending, twisting and crushing forces. The protective outer layer shall also protect the optical fibres against environmental degrading factors such as Aeolian vibrations, moisture and large temperature variations.

3.1.2 The stranded bare conductor shall consist of one or more layers of all aluminium alloy wires,

to provide the same electrical and mechanical characteristics as a conventional overhead ground wire.

3.1.3 Designs where, should bird-caging of the outer layer of the conductor occur, because any

synthetic material containing the fibres could be exposed to pollutants in the atmosphere or ultra-violet radiation from the sun, will not be accepted.

3.2 Optical Fibre Properties 3.2.1 The optical fibre shall be single mode. 3.2.2 The fibre shall be manufactured by the Modified Chemical Vapour Deposition method or

similar. 3.2.3 The fibres shall have a diameter of 9,3 m 5%.

Page 7 of 13



3.2.4 The cladding of the fibres shall have a diameter of 125 m 5%, and shall comply with ITU-T recommendation G.652. The fibres shall be capable of operating in both the 1300nm and 1500nm wave-lengths, depending on specific link requirements.

3.2.5 There shall be no measurable long term optical attenuation change due to the temperature

rise associated with fault current flowing in the earthwire, or a lightning strike on the earthwire. Short term optical attenuation change due to these phenomena shall be less than 0,05 dB/km.

3.2.6 No fibre splices are permitted in any continuous length of OPGW. 3.2.7 Attenuation uniformity shall be tested at both 1300nm and 1550nm with a pulse width not

exceeding 1 m. Fibres with points or steps of discontinuity greater than 0,2 dB shall not be accepted. For fibre length in excess of 1 000m the attenuation coefficient over the length of the fibre shall not vary by more than 0,2 dB/km measured on consecutive 1 000m pieces.

3.2.8 The fibres shall be proof tested to an equivalent of more than 8 N for 1 second, corresponding

to 0,7 GN/m2 or 1% strain. 3.2.9 Micro bend resistance shall be tested by a method specified in the relevant specification (for

example: 100 turns around a 60mm mandrel at 1550nm). During testing the attenuation increase shall be less than the value specified in the relevant Standard.

3.3 Optical Fibre Carrier (Central Protection Unit / Tube) 3.3.1 The central optical fibre protection unit / tube shall house the optical fibres, and protect them

from damage caused by large temperature variations produced by lightning or fault currents, moisture ingress and mechanical forces such as crushing, bending, twisting, tensile stress and Aeolian vibrations.

3.3.2 The optical fibre protection unit / tube may include a stainless steel or aluminium / aluminium

alloy tube or channelled rod. However, other designs may be considered. 3.3.3 The optical fibre unit design shall be such that no moisture shall be able to penetrate and

come in contact with the fibres. 3.3.4 No fibre shall be under any strain in an installed cable, when such cable is subjected to

normal operating conditions. 3.3.5 The optical fibre unit shall be so designed as to minimise hydrogen absorption by the fibres. 3.4 Armour (Outer Earthing Conductor Stranding) 3.4.1 Tenderers must note that the conductor is to be used in a harsh coastal environment close to

the sea. It is imperative that every effort be made to reduce corrosion in service to a minimum.

3.4.2 The OPGW Stranded AAAC must be so designed as to provide the equivalent weight,

breaking strength, lightning (fusing) and anti-corrosion characteristics, as well as satisfying the short circuit requirements, as conventional overhead ground wire.

Where the weight (W) and breaking strength (T) vary from the standard earth wire, the W/T ratio must be as close as possible to the existing earth wire.

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3.4.3 The ground wire shall consist of all aluminium alloy and shall comply in all respects with the requirements of BS 3242.

The conductor strands shall be drawn from solution treated (high temperature heat soaked and quenched) redraw wire. The drawn conductor shall be artificially aged by annealing for several hours at a suitable low temperature to improve the corrosion resistance and increase conductivity as recommended by the suppliers of the redraw wire.

3.4.4 The stranding of each layer of the conductor shall be as close and even as possible. The

direction of lay shall be reversed in successive layers. The outer most layer shall be right handed.

3.4.5 The wires shall be so stranded that, when the complete OPGW is cut, the individual layers

can easily be regrouped. 3.4.6 The finished wires shall contain no joints or splices. 3.4.7 The conductors shall be greased using a process, which ensures that all layers are greased

and all interstices filled. The grease shall have suitable properties of pseudoplasticity, thixotropy and syneresis. (The grease shall be “cable guard” or an approved equal).

3.4.8 The fibre carrier (buffer) shall be of the appropriate diameter and shall be the centre strand. 3.4.9 Where the material of the buffer differs from the material of the strands, an aluminium alloy

coating similar in material to the rest of the strands shall be applied to the buffer to prevent galvanic corrosion.

3.4.10 Where used as one of two ground wires the optical fibre ground wire shall have mechanical

characteristics that will permit it to be sagged compatibly with its companion AAAC ground wire. The still air 15oC tension shall not exceed 20% of the ultimate tensile strength of the optical fibre ground wire. This is essential in order to maintain clearance above the top phase conductor and is desirable from an aesthetic point of view.

3.5 Information to be supplied by the Manufacturer Provide the following: - 3.5.1 Full details of the cable construction are to be provided, including details of the measures

taken to minimise hydrogen absorption by the fibres. 3.5.2 Full details of primary and secondary coatings are to be supplied. If chemical stripping is

recommended, then the chemical composition of the coatings and recommended solvents are to be provided.

3.5.3 If mechanical stripping is recommended, then a suitable stripping device must be specified. 3.5.4 Details are to be provided of the colour coding system utilised for fibre identification. 3.5.5 Details are to be provided of the measures taken to prevent water ingress into the fibre units. 3.5.6 The joint boxes to be used shall be to the Engineer’s approval. All necessary particulars shall

be provided as to construction details, degree of protection offered, etc., of the units proposed for installation.

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3.6 Installation and Commissioning 3.6.1 Jointing 3.6.1.1 The optical fibre cable supplier will be responsible for the jointing and must therefore be

equipped with all the necessary specialised tools and test equipment and have staff capable of performing such a function.

3.6.1.2 Jointing of the fibres shall be done at ground level; where after the joint box shall be pulled

up and mounted above the anti-climbing guard. 3.6.1.3 All joints shall be of the fusion type, and the average loss per joint for the whole route shall

be less than or equal to 0,1 dB. No single joint shall have a loss greater than 0,15 dB. The connector losses at the two terminal stations are excluded.

3.6.2 Terminations 3.6.2.1 General The optical protective ground wire must be terminated at the terminal gantry / tower in a tower-mounted joint box, at each end of the overhead line. 3.6.2.2 Underground Optical Fibre Cable

a) An underground optical fibre cable for connection between the terminal gantries / towers and the substation buildings will be required and shall be steel wire armoured with individually identified optical fibre cores with a strength member and a black coloured outer PVC sheath.

b) The underground cable shall be laid from the tower-mounted joint box, through ducts provided

by Council, to the indoor termination equipment.

c) The underground optical fibre cable must be terminated in the substation building in a wall-mounted indoor termination box. Each optical fibre in the indoor termination box must be spliced into a 5m length of connectorised wire pigtail. (Others will supply the indoor termination boxes).

d) The optical characteristics of the underground cable shall be the same as for the overhead

fibre optic cable.

e) The cable shall be supplied, installed and made-off by the contractor. 3.6.3 Joints, Clamps and Distribution / Joint Boxes The OPGW joint boxes shall be weather proof and vandal proof. The OPGW conductor suspension clamps and end make-off arrangements shall be as specified by the manufacturer. A drawing for suspension and tension clamps and distribution / joint boxes must be submitted with the tender for approval.

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3.6.4 Stringing Stringing of the optical fibre cable will be done by the main contractor under the supervision of the fibre optic supplier at the same time as the line erection. The maximum permissible pulling tension for the optical fibre cable offered and the bending diameter for stringing must be specified in the tender. 3.6.5 Fibre Optic Testing Procedure 3.6.5.1 The aim of these tests is to prove to the Engineer that the fibre optic installation is acceptable. 3.6.5.2 The supplier shall satisfy himself that the cable and fibres on each cable reel supplied to site

are intact, prior to giving permission for stringing / installation to commence. Details of such tests are to be provided to the Engineer, together with the results obtained.

3.6.5.3 After installation, the complete system shall be tested from end to end. The Engineer shall be

given the opportunity to carry out final acceptance testing in conjunction with the supplier’s staff. The Engineer’s attendance shall not relieve the supplier of his responsibility for the satisfactory performance of the equipment during site testing, and there after through to the end of the warranty period.

3.6.5.4 Each fibre in the installation is to be tested, from both ends. 3.6.5.5 Optical Time Domain Reflecto-meter (OTDR) Traces are to be provided for the entire length

of the fibre, indicating the distance to joints, the total length of the fibre, and the loss at each joint.

3.6.5.6 For testing purposes, each OTDR Trace must be labelled with the following information: -

Date;

Fibre optic cable description;

Fibre number; and

The end from which the test is being performed. 3.6.5.7 The total end-to-end loss must be measured, using a light source and an optical power meter.

An average of the measurements from both ends shall be deemed to quantify the system loss. Losses shall be measured at both 1300nm and 1550nm wavelengths.

3.6.5.8 All the information must be summarised in table form as shown in the example in Annex A of

this document. 3.6.5.9 Commissioning shall be done in close co-operation with, and to the full satisfaction of the

Engineer’s Communication’s Division. 3.6.5.10The Engineer reserves the right to have several Technicians actively participating in the fibre

section link tests, with the object of them gaining intimate knowledge of the testing procedures.

4. TRAINING Tenderers must advise the following details regarding training of Electricity Department staff including a price breakdown: - 4.1 Fibre optic repairs;

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4.2 Fibre optic testing; 4.3 Fibre optic installation; 4.4 The successful tenderer must supply three copies of all maintenance manuals. 5. QUALITY 5.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout. 5.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract. 6. DRAWINGS 6.1 General All drawings shall be to scale and fully detailed. All important dimensions shall be given. Drawings submitted for approval shall be in triplicate and the contractor shall supply any further copies upon request. The original drawings shall be prepared in such a manner that they comply fully with the requirements of SABS 0111 Part 1: Engineering Drawing – General Principles, in order that acceptable microfilm versions can be made from them. Where the supplier uses a CAD drawing system, he shall provide copies of the drawings on an AutoCAD compatible file. 7. INSTRUCTION / MAINTENANCE MANUALS Triplicate copies of installation, operation and maintenance manuals for the equipment are to be submitted before delivery. 8. MARKING AND LABELLING 8.1 Labels All apparatus, where required / necessary, is to be clearly and indelibly labelled to ensure correct operation and safety both to the plant and to the operators. Labels not exposed to the weather shall be of engraved laminated Traffolyte or equal approved black material having white lettering or, in the case of danger notices, it shall have red lettering on a white background.

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Labels and diagram plates exposed to the weather, shall be of stainless steel or equivalent with all information permanently applied by etching, engraving or stamping. 9. TESTS 9.1 Type Test Certificates Certified copies of type and special test certificates, showing the results of type tests (design tests) performed on equipment similar to that being offered are to be included in the tender. 9.2 Routine Test Certificates Certified copies of test certificates, showing the results of routine tests performed, are to be supplied prior to delivery of the equipment. 10. TENDER LITERATURE / DOCUMENTATION Descriptive literature and drawings showing dimensions must accompany the tender offer. 11. TECHNICAL BACK-UP Details of technical back-up / repair facilities available in South Africa are to be provided. 12. SPARES AND SPECIAL TOOLS Tenderers must advise the following details regarding spares and services with a price breakdown: - 12.1 Recommended length of spare optical fibre cable; 12.2 Recommended optical cable testing and splicing equipment; 12.3 The extent and capability of the optical fibre supplier’s service facility. Details shall include the

response time to a request for jointing and testing of the optical fibre cable, should this be necessary once the line is in service.

13. INSTALLED USER BASE Tenderers must state how long the OPGW offered has been in production, along with the names and addresses of at least two South African users who can be contacted for comment on the equipment.

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REV NO.

DETAILS

AUTHOR


Page 1 of 12

REV – DRAFT 1 13 DECEMBER 2001PEE STANDARD NO: 126

TRENCHING AND FOUNDATIONS (OUTDOOR EQUIPMENT) FILED-F:\DATA\STANDARDS\PEE_STD\STD 126 – TRENCHING AND FOUNDATIONS (OUTDOOR EQUIPMENT)\Std 126.doc




________________

TRENCHING, BACKFILLING & FOUNDATIONS FOR OUTDOOR ELECTRICAL EQUIPMENT IN

MAIN SUBSTATIONS

____________________________

REV – DRAFT 1 13 DECEMBER 2001

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BLANK PAGE

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TRENCHING, BACKFILLING AND FOUNDATIONS FOR OUTDOOR

ELECTRICAL EQUIPMENT IN MAIN SUBSTATIONS

TABLE OF CONTENTS

PAGE 1. SCOPE 5

2. REFERENCES 5

3. DESIGN 6

4. EARTH WORKS 6 4.1 Site Preparation 4.2 Marking Out 4.3 Excavations (Foundations / Footings / Plinths) 4.4 Excavations (Cable Trenches) 4.5 Deep Excavations 4.6 Classes of Excavations 4.7 Dealing with Water 4.8 Backfilling (Cable Trenches) 4.8.1 The as-built data for the exact positions of buried services shall be

taken before backfilling starts

4.8.2 Bedding

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PAGE 4.8.3 Bedding Material 4.8.4 Bricks over MV Cable 4.8.5 Backfilling Material 4.8.6 Shortfall of Bedding and Backfill Material 4.8.7 Compaction

5. CONCRETE WORKS FOR FOOTINGS / FOUNDATIONS / PLINTHS FOR THE ERECTION OF OUTDOOR ELECTRICAL EQUIPMENT

8

5.1 Height above Ground Level 5.2 Strength Concrete 5.3 Reinforcing 5.4 Placing and Finishing

6. MEASUREMENT FOR PAYMENT 10



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1. SCOPE This Standard provides for the following substations: -

The excavation of cable trenches for the earthing grid, transformer MV power cables and auxiliary cables and backfilling and compaction of the same;

The design, excavation for and casting of footings / foundations / plinths for the erection of

outdoor electrical equipment. 2. REFERENCES The following standards are referred to in the text below and shall apply where quoted: - SABS 471 : Portland Cement (ordinary, rapid-hardening and

sulphate-resisting)

SABS 718 : Aggregates for Concrete

SABS 920 : Steel Bars for Concrete Reinforcement

SABS ENV 196 (Parts 2, 4, 6, 7, 21) : Methods of Testing Cement

SABS ENV 197 (Parts 1 and 2) : Composition, Specification and Conformity Criteria for Cements

SABS ENV 413 (Parts 1 and 2) : Masonry Cement

COP 10.1 (Section 2) : Climatic, Atmospheric and Environmental Conditions

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COP 10.1 (Section 9) : Safety Factors and other principles applicable to the Mechanical Strength Calculations of Outdoor Electrical Equipment, their Support Structures and Foundations

Act 85 of 1993 : Occupational Health and Safety Act 3. DESIGN The contractor shall be responsible for the design of the footings / foundations / plinths covered by the Project Specification and shall take cognisance of the following in the design thereof: -

The climatic, atmospheric and environmental conditions outlined in the Code of Practice Number 10.1 – Section 2 shall be considered.

The Safety and other principles outlined in the Code of Practice Number 10.1 – Section 9

shall apply.

Foundations shall be designed and the associated drawings signed by an ECSA registered Professional Engineer with at least 2 year’s relevant experience after registration as a Professional Engineer.

Drawings of footings / foundations / plinths shall clearly indicate the maximum forces and

turning over moments (in all directions) for which they have been designed, together with the safety factors used and other assumptions made, e.g. bearing pressure of the ground.

Footings / foundations / plinths for outdoor electrical equipment, whether mounted directly

(e.g. power transformers) or onto support structures, shall be cast with a minimum concrete strength of 20 Mpa.

Foundations shall be case in situ.

4. EARTH WORKS 4.1 Site Preparation The site where the foundations are to be cast is to be cleared of all shrubs and vegetation and disposed of to designated sites by the contractor. 4.2 Marking Out The foundations are to be clearly marked out on the ground to the dimensions shown on the drawings. Should the contractor excavate to dimensions in excess of those stipulated or permitted, he shall fill in the excess at his own expense in the manner specified or approved by the Employer. 4.3 Excavations (Footings / Foundations / Plinths) The excavations shall be dug to the neat lines marked out to the depths indicated on the drawing or to such greater depths as may be ordered or approved to ensure satisfactory founding. Except where otherwise specified or ordered, the excavation shall be carried out and trimmed to the outline of the concrete work shown on the drawings. The excavated surfaces will act as forms for the concrete work. Prior to the casting of any concrete, the bottom of the excavation shall be cleared of all loose material or soft material.

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4.4 Excavations (Cable Trenches) Trenches shall be marked out and dug in line and at right angles to the geographic layout of the outdoor switch bays and / or control room. Diagonal trenches are not acceptable. Trenches shall be sufficiently deep to allow the following minimum coverings from the top of cables: -

Medium Voltage Cable : 600mm

Low Voltage and Auxiliary Cables : 600mm Refer to PEE Standard Number 125 for detail on earthing conductor. 4.5 Deep Excavations The contractor’s attention is drawn to the relevant clauses in OHS – Act relating to excavation deeper than 1,5m. Where excavations are not adequately shored and supported and the sides collapse, no extra payment will be considered and the contractor shall remove the collapsed soil and replace and compact the soil after the foundations have been cast. The same applies where excavations have been damaged by storm water. 4.6 Classes of Excavations Excavations shall be classified and paid for as follows: -

Soft Excavations Material that can be loosened and removed by using hand tools and / or the bucket only of a back-acting excavator.

Intermediate Excavations

Material that, in the opinion of the Engineer, cannot be economically loosened without the assistance of pneumatic tools other than the bucket of a back-acting excavator.

Rock

Material that, in the opinion of the Engineer cannot be economically fragmented and loosened, except by drilling and blasting or the use of rock-breaking equipment other than what can be operated by hand.

4.7 Dealing with Water Excavations must be kept dry and free of water as far as possible. No cables are to be laid in water. Payment for dealing with water shall be based on dayworks rates. 4.8 Backfilling (Cable Trenches) 4.8.1 The as-built data for the exact positions of buried services shall be taken before back-

filling starts 4.8.2 Bedding Cables shall be bedded below and above as follows: -

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Medium voltage cable : 100mm

Low voltage and auxiliary cables: 50mm 4.8.3 Bedding Material Material for bedding electricity supply and auxiliary cables shall be a selected soil of granular (sandy) nature, free of clay, vegetation, foreign matter, lumps and stones exceeding 15mm in size. Bedding material shall preferably be selected from the excavations on site and shall be sifted. Where insufficient quantities of suitable bedding material exist on site, it shall be imported. 4.8.4 Bricks over MV Cable One layer of clinker brinks (to be supplied by the contractor) shall be placed directly on top of the bedding in respect of MV cables to indicate the position thereof. Approximately 4.5 bricks shall be placed per meter of cable. 4.8.5 Backfilling Material Backfilling other than bedding, shall contain little or no vegetable matter. It shall also exclude stone of average dimension exceeding 150mm. It shall not contain rubble or debris in order that it can be placed without significant voids and so compacted as to avoid significant settlement. 4.8.6 Shortfall of Bedding and Backfill Material Where there is a shortfall of suitable bedding or backfill material, material shall be imported from a recognised source. 4.8.7 Compaction The backfill material shall be at optimum moisture content. Each layer of backfill shall be placed to a thickness (after compaction) of 150mm. The bedding blanket shall only be lightly compacted to avoid damage to the cables. Backfill material other than bedding shall be compacted to 98% of Proctor density using hand stampers. 5. CONCRETE WORKS FOR FOOTINGS / FOUNDATIONS / PLINTHS FOR THE ERECTION OF

OUTDOOR ELECTRICAL EQUIPMENT 5.1 Height above Ground Level The finished cast level of all footings / foundations / plinths shall be at least 150mm above final ground level. The finished height of the power transformer plinths shall be determined in co-operation with the manufacturer of the transformers, but shall in any event be not less than 150mm above final ground level. The tops of all foundations shall be horizontal and level.

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5.2 Concrete Strength The concrete used in the footings / foundations / plinths shall be of a strength of at least 25 MPa. Either concrete mixed on site or ready-mixed concrete is acceptable as long as it meets the required specifications. The contractor could be called upon to take sample cubes and have them tested to ensure that the required concrete strength is achieved. The concrete shall be mixed without excessive water. The materials used in the strength concrete shall meet the following criteria: -

Cement Cement used shall be ordinary Portland Cement or when required, rapid-hardening cement in accordance with SABS 471.

Cement that is stored on site shall be kept under cover that provides proper protection against

moisture and other factors that may promote deterioration. Contaminated or spoiled cement may not be used and must be removed from site.

Aggregates

All aggregates for concrete shall comply with the requirements of SABS 1083.

Water Water shall be clean and free from injurious amounts of acids, alkalis, organic matter and other substances that may impair the strength or durability of concrete.

5.3 Reinforcing

Design Where reinforcing is required in terms of the design, the concrete shall be suitably reinforced with steel to withstand the maximum loadings to which it could be subjected.

Material

The reinforcing of bars shall comply with the relevant requirements of SABS 920. Welded steel fabric shall comply with the relevant requirements of SABS 1024.

Storage

Steel shall be stacked off the ground as to prevent distortion, and shall be prohibited from aggressive environments of contamination. The steel must be clean from oil, paint or loose rust.

Lapping and Tying

All joints are to be lapped by at least 25 times the bar diameter and tied with 1.6mm annealed steel wire.

Bending and Working

All bending of steel must be done cold.

Cover Reinforcing is to be held securely in place during casting and is to have a minimum cover of at least 75mm.

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5.4 Placing and Finishing The Engineer shall be given at least 2 (two) days’ written notice of the contractor’s intention to cast footings / foundations / plinths. The Engineer may want to inspect excavations before placing of the concrete. The bottom of excavations shall be damp to optimum moisture content and compacted to 98% of Proctor density before any concrete is cast. Shuttering must be sturdy, square and level. Properly supported joints in shuttering shall be sealed to prevent seepage of cement from the concrete. Concrete shall be cast without interruption. In cases where it is not practical to do so, the written approval of the Engineer shall be obtained in which case approved jointing methods shall be employed. Vacuum system shall be applied during and after placing to ensure removal of trapped air / air voids in the concrete. Concrete shall not be cast when the temperature is below 4oC. Concrete shall be protected against frost or any other weather conditions, which may influence the setting and curing of the concrete. No loads may be applied to any concrete before it has been properly cured. Foundations shall have no sharp corners or edges. Corners and edges shall be levelled at 45o with a width of 50mm. Immediately after the structures have been installed and finally aligned, all the base plates shall be grouted-in, using a non-shrink type of grouting, strictly in accordance with the supplier’s instructions. The grouting shall be finished off where it protrudes beyond the base plates such that a run-off for water is provided. 6. MEASUREMENT FOR PAYMENT Tenders shall be submitted with detail regarding the expected quantities for the following items. Payment shall be based on actual quantities encountered on site up to a maximum of the tendered quantities. The tendered quantities should therefore constitute maximum quantities. 6.1 Excavation for footings / foundations / plinths and trenches m3

6.2 Backfilling of trenches m3

6.3 Laying of earth conductor and auxiliary cables m3

6.4 Concrete for footings / foundations / plinths m3

6.5 Importing bedding and backfill material (the price includes transport within a radius of

15km) m3

6.6 Disposal of soil (the price includes transport within a radius of 15km) m3

6.7 Steel for reinforcing m3

6.8 Transport beyond a radius of 15km (only applicable to 6.5 and 6.6) m3

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7. QUALITY 7.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout. 7.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract.

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REV NO.

DETAILS

AUTHOR


0

New Draft

PG

5 November 1999

1

PG

13 December 2001

Page 1 of 7


COMPOSITE STRING INSULATORS FILED-F:\DATA\STANDARDS\PEE_STD\STD 134 – COMPOSITE STRING INSULATORS (66 – 132 kV)\Std 134.doc




________________

COMPOSITE STRING INSULATORS

22 – 132 kV

____________________________


Page 2 of 7



BLANK PAGE

Page 3 of 7






COMPOSITE STRING INSULATORS 22 – 132 kV

TABLE OF CONTENTS

PAGE 1. SCOPE 4

2. REFERENCES 4

3. SAFETY FACTORS 4


5. HOUSING 5

6. END FITTINGS 5

7. CONNECTING LENGTH 5

8. INSULATION CO-ORDINATION 6

9. STRENGTH CLASS 6

10. ACCESSORIES 6

11. CORROSION 6

12. ACCESSORIES 6


Page 4 of 7







1. SCOPE This specification provides for the design, manufacture, testing, supply and delivery of string insulators of the composite type. 2. REFERENCES The insulators shall, where applicable, be manufactured and tested in accordance with the relevant requirements of the standards listed below: - SANS IEC 61109 : Composite Insulators for AC Overhead Lines with a Nominal Voltage

greater than 1 000 V – Definitions, Test Methods and Acceptance Criteria

SANS IEC 61466-1 : Composite String Insulators for Overhead Lines with a Nominal Voltage greater than 1 000 V – Standard Strength Classes and Fittings

SANS IEC 61466-2 : Composite String Insulator Units for Overhead Lines with a Voltage greater than 1 000 V. Dimensional and Electrical Characteristics

The following standards are referred to in the text below and are only applicable where specifically referred to in the specification: - SABS 178 – 1970 : Non-current carrying line fittings for Overhead Power Lines

SABS 763 : Galvanising

PEE COP 10.1 : Common Rules 3. SAFETY FACTORS The safety factors applicable to the insulators and accessories shall be in accordance with the latest version of OHS Act (i.e. 2.5 in 1999).

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4. QUALITY 4.1 General All materials and equipment supplied and / or installed in terms of this Standard shall be new and in fully merchantable condition. Workmanship shall be of a professional standard carried out by qualified and skilled tradesmen / women to the satisfaction of the Engineer. Normal accepted industry expertise is expected throughout. 4.2 Quality Assurance Provisions The Tenderer will be required to submit documentary proof of his quality control process or whether his firm is listed by the South African Bureau of Standards as a firm whose quality management system complies with SABS ISO 9000, Quality Systems, in respect of products covered by this contract. 5. HOUSING Only housings manufactured from elastomers shall be considered. Housings manufactured from resins and fluorocarbons shall NOT be considered. 6. END FITTINGS The line end fittings shall be as follows: - Voltage (kV)

Support End Fitting

Line End Fitting

Alignment

Hole Size

22

Clevis

Tongue

In Line

18mm

66

Clevis

Tongue

In Line

18mm

132

Tongue

In Line

18mm

7. CONNECTING LENGTH The connecting length (centre to centre) shall be as follows: - Voltage

Connecting Length

22 kV 372mm 66 kV 895mm 132 kV 1 500mm

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8. INSULATION CO-ORDINATION The design and test values for the Standard Lightning Impulse Withstand Voltage, the Power Frequency Withstand Voltage and the Minimum Creeping Distance shall be in accordance with PEE Code of Practice Number 10.1. 9. STRENGTH CLASS The insulators shall be capable of withstanding the following working tensile strengths after the safety factors in Clause 3 have been taken into account: - Voltage (kV)

Tensile Strength (kN)

22

70

66

70

132

70

10. ACCESSORIES All clevis ends are to be supplied with a clevis cotter pin fitted with a flat washer and stainless steel hump-back retainer pin. 11. CORROSION All ferrous parts shall be hot-dip galvanised to SABS 763. 12. ACCESSORIES All accessories, including strain clamps, suspension clamps, arcing horns, turnbuckles, yoke plates, etc. shall be manufactured to SABS 179 – 1970.

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