SANS 10198-11-2010 The selection handling and installation of electric power cables of rating not exceeding 33 kV Part 11 Jointing and termination of screened polymeric-insulated c.pdf

1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA

2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any

3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-23287-0 SANS 10198-11:2010Edition 2 SOUTH AFRICAN NATIONAL STANDARD The selection, handling and installation of electric power cables of r

4、ating not exceeding 33 kV Part 11: Jointing and termination of screened polymeric-insulated cables Published by SABS Standards Division 1 Dr Lategan Road Groenkloof Private Bag X191 Pretoria 0001Tel: +27 12 428 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS SANS 10198-11:2010 Edition 2 Table of chang

5、es Change No. Date Scope Foreword This South African standard was approved by National Committee SABS TC 66, Electric cables, in accordance with procedures of the SABS Standards Division, in compliance with annex 3 of the WTO/TBT agreement. This document was published in January 2010. This document

6、supersedes SABS 0198-11:1988 (edition 1 as modified by amdt 1:1990). SANS 10198 consists of the following parts, under the general title The selection, handling and installation of electric power cables of rating not exceeding 33 kV: Part 1: Definitions and statutory requirements. Part 2: Selection

7、of cable type and methods of installation. Part 3: Earthing systems General provisions. Part 4: Current ratings. Part 5: Determination of thermal and electrical resistivity of soil. Part 6: Transportation and storage. Part 7: Safety precautions. Part 8: Cable laying and installation. Part 9: Jointin

8、g and termination of extruded solid dielectric-insulated cables up to 3,3 kV. Part 10: Jointing and termination of paper-insulated cables. Part 11: Jointing and termination of screened polymeric-insulated cables. Part 12: Installation of earthing system. Part 13: Testing, commissioning and fault loc

9、ation. Part 14: Installation of aerial bundled conductor (ABC) cables. NOTE The first five parts deal with factors to be taken into account when an electrical distribution system is being designed. The last nine parts deal with the practical aspects of handling and installing cables. Annexes A to C

10、are for information only. SANS 10198-11:2010 Edition 2 1 Introduction This part of SANS 10198 incorporates the techniques used for the jointing and termination of screened polymeric insulated cables using dry-type accessories including heat-shrink, cold-shrink and other cold-applied technologies. Th

11、e methods described in this part of SANS 10198 cover medium voltage multi-core cables but the same principles apply to single-core cables. The construction of screened polymeric insulated cables referred to in this standard is based upon the requirements of SANS 1339. SANS 10198-11:2010 Edition 2 2

12、This page is intentionally left blank SANS 10198-11:2010 Edition 2 3 Contents Page Foreword Introduction 1 Scope . 5 2 Normative references 5 3 Definitions and abbreviations 6 4 Common procedures for cable jointers. 7 4.1 Preliminaries . 7 4.2 Safety 7 4.3 Moisture test (crackle test) on the impregn

13、ated paper-insulated cable side of transition joints. 8 4.4 Common jointing practices . 8 4.5 Stress control in joints and terminations to prevent partial discharge 9 4.6 Voids . 11 4.7 Moisture 11 5 Jointing 11 5.1 Preparation . 12 5.2 Cable preparation . 13 5.3 Connecting of conductors. 16 5.4 Fer

14、rule stress control 17 5.5 Dry-type joints: heat-shrink. 17 5.6 Dry-type joints: cold-shrink . 19 5.7 Transition jointing systems . 20 6 Termination . 206.1 General . 20 6.2 Preparation . 21 6.3 Cable preparation . 22 6.4 Fitting of lugs. 26 6.5 Termination tail outer tubes and the sealing of the in

15、terface between the outer tube and the lug barrel 27 6.6 Types of terminations used in air-filled enclosures. 28 6.7 Outdoor terminations 31 SANS 10198-11:2010 Edition 2 4 Contents (concluded) Page Annex A (Informative) Jointers tool kit. 32 Annex B (Informative) Earth-fault path in single-core cabl

16、e systems 33 Annex C (Informative) Types of terminations in air-filled enclosures. 34 Bibliography. 36 SANS 10198-11:2010 Edition 2 5 The selection, handling and installation of electric power cables of rating not exceeding 33 kV Part 11: Jointing and termination of screened polymeric-insulated cabl

17、es 1 Scope 1.1 This part of SANS 10198 covers: a) the jointing and termination of medium-voltage screened polymeric cables; and b) the transition jointing of impregnated paper-insulated to screened polymeric (e.g. XLPE) insulated cables. This part of SANS 10198 excludes installation in hazardous are

18、as and undergroud mines. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced documents (including any amendments) applies.

19、Information on currently valid national and international standards can be obtained from the SABS Standards Division. SANS 876, Cable terminations and live conductors within air-filled enclosures (insulation co-ordination) for rated a.c. voltages from 7,2 kV up to and including 36 kV. SANS 6281-4, T

20、est methods for impregnated paper-insulated electric cables Part 4: Tests after installation. SANS 10198-1, The selection, handling and installation of electric power cables of rating not exceeding 33 kV Part 1: Definitions and statutory requirements. SANS 10198-7, The selection, handling and instal

21、lation of electric power cables of rating not exceeding 33 kV Part 7: Safety precautions. SANS 10198-10, The selection, handling and installation of electric power cables of rating not exceeding 33 kV Part 10: Jointing and termination of paper-insulated cables. SANS 10198-11:2010 Edition 2 6 3 Defin

22、itions and abbreviations 3.1 For the purposes of this document, the definitions in SANS 10198-1, and the following apply: 3.1.1 air-filled enclosure metallic enclosure designed to protect the ends of cables, bushings, current transformers or live conductors 3.1.2 air-insulated termination (type 1 te

23、rmination) air-filled enclosure within which the cable cores are electrically terminated by stress control appropriate to the cable design and voltage with air being the sole insulation for the terminal connections 3.1.3 cable jointer person skilled in the craft of jointing and terminating electric

24、cables 3.1.4 constant force spring CFS roll spring used to ensure continuous electrical and mechanical contact between an earthing conductor and the underlying metallic screen, metallic sheath or armour 3.1.5 jointing technique of applying a joint or termination on a cable 3.1.6 reference point refe

25、rence line used for measurement purposes when jointing or terminating 3.1.7 screened separable connector termination (type 4 termination) air-filled enclosure within which the cable cores are terminated with screened separable connectors 3.1.8 shrouded insulation termination (type 2 termination) air

26、-insulated termination that has additional, unscreened, local insulation enhancement typically consisting of bushing protection or taping along with a heat shrink, cold shrink or slip-on cover at the terminal connections 3.1.9 support bush circular metallic support that is inserted beneath the wire

27、armouring. For single core cables, the support bush is required to be non-magnetic. 3.1.10 transition joint any joint between dissimilar cables 3.1.11 unscreened separable connector termination (type 3 termination) air-insulated termination that is fitted with unscreened separable connectors SANS 10

28、198-11:2010 Edition 2 7 3.2 The following abbreviations are used in this part of SANS 10198: CFS Constant Force Spring MWFT Metallic woven fabric tape XLPE Cross-linked polyethylene PPE Personal protective equipment 4 Common procedures for cable jointers NOTE A jointers basic tool kit is described i

29、n annex A. 4.1 Preliminaries 4.1.1 Set up all necessary safety barricading (for example warning signs) around the work site. 4.1.2 Check the accessory to be used in order to ensure that it is suitable for the type and size of cable to be jointed or terminated. 4.1.3 Before starting to make a joint o

30、r termination, ensure that all materials listed in the installation instructions bill of materials have been provided. Verify the specified lengths of component materials (e.g. tubes, braids and tapes). Where relevant, check that the expiry dates of components with a limited shelf life have not been

31、 exceeded. 4.1.4 Read the installation instructions carefully and follow the steps in the correct sequence. 4.1.5 Do not bend the cable tighter than the minimum recommended bending radius. 4.1.6 Place a protective cover over loose dirt or sand especially under the working area. 4.1.7 If there is any

32、 risk of adverse weather during jointing operations, set up a jointing tent and ensure that it is well-ventilated. 4.1.8 Use the recommended tool set (see annex A) and lay out the tools on a tool tray so that they are kept clean and easy to reach. 4.1.9 Where applicable, ensure that all tools (e.g.

33、torque wrench, crimping tools, verniers and tape measures) are correctly calibrated (i.e. that they are within their calibration validity period). 4.1.10 If work is to be performed in an existing permanent manhole, cable tunnel or joint bay below ground, ensure that all toxic gases have been removed

34、 before anyone enters the enclosure. Check for the presence of gases by using a gas detector or by detecting any characteristic odours (e.g. petrol, hydrogen sulfide). DO NOT use a naked flame to test for the presence of gas. Take the necessary precautions to prevent flooding. 4.1.11 Seal the ends o

35、f all cables that are not immediately jointed or terminated using an approved method (e.g. heat-shrink cable end seal with interior deposits of moisture-proof adhesive that is activated by the shrinking operation). 4.1.12 Ensure that both hands are kept clean and dry. 4.2 Safety 4.2.1 Apply all the

36、safety measures recommended in SANS 10198-1 and SANS 10198-7. SANS 10198-11:2010 Edition 2 8 4.2.2 If the jointing bay is wet, a) arrange for the effective drainage of water from the trench and joint bay by the construction of sumps and the installation of water pumps; b) use waterproof sheets under

37、 the jointing area; c) use rubber mats and dry timber battens to provide secure flooring; and d) wear appropriate personal protective equipment (PPE). 4.2.3 Check the relevant “Permit to Work“ (see annex A in SANS 10198-7:2004). Follow the applicable procedures (e.g. witness the earthing and spiking

38、 of cables) and sign the workmans declaration before attempting to start any joint operations 4.2.4 Treat all other cables within the cable trench and jointing bay as live. Take care to prevent any damage to other cables or services within the trench or jointing bay. Do not interfere with other cabl

39、es or services (e.g. do not disturb, stand, sit or lean upon them). 4.2.5 Keep the test site area clear of flammable material. When using exposed flames (e.g. for heat-shrink accessories), keep the flammable gas cylinder out of the jointing bay of the cable trench at all times. 4.3 Moisture test (cr

40、ackle test) on the impregnated paper-insulated cable side of transition joints Carry out the moisture test in accordance with SANS 6281-4 on the outermost and innermost belt papers (or MWFT, if the cable is screened) and the outermost and innermost papers on each core. If any test shows signs of moi

41、sture in the cable, cut it back to where the paper is dry. It is important that the temperature of the oil is verified before submerging the papers. NOTE Should only a small number of bubbles appear on the surface of the test medium, this provides an indication of air bubbles on the impregnated pape

42、r and not necessarily of moisture. The presence of moisture will result in a series of bubbles rising to the surface of the test medium for a number of seconds (accompanied by a distinctive crackling sound and foaming), until all moisture has been removed. 4.4 Common jointing practices 4.4.1 Clean a

43、ll surfaces before the application of heat-shrink, cold-shrink or slip-on components. Position components away from dirt, grease and foreign substances. NOTE The bags in which the outer components (tubes) are supplied are suitable for use as protective coverings over the cable outer sheath. This pre

44、vents the parked tubes from becoming soiled. 4.4.2 Abrade and clean surfaces onto which moisture block adhesives are applied (e.g. mastics or heat-shrink sleeves that have interior deposits of moisture-proof adhesive that is activated by the shrinking operation), in order to ensure good contact. NOT

45、E The cable outer sheath can be abraded by using aluminium oxide paper, a file or a hacksaw blade. 4.4.3 For shrinking of heat-shrinkable components, use a propane gas torch. Adjust the torch to obtain a soft blue flame with a yellow tip. Avoid a pencil-like blue flame. Keep the torch aimed in the d

46、irection of shrinking and follow the shrinking sequence given in the installation instructions. Keep the flame moving circumferentially around the tubing in order to ensure even wall thickness and keep moving continuously to prevent scorching. Take special care underneath the tube or in areas SANS 1

47、0198-11:2010 Edition 2 9 where the heat can not be applied evenly. After shrinking, the tubing and moulded parts shall be smooth and free of wrinkles or “cold-spots“. Always take care so as to avoid entrapping air. 4.4.4 If heat shrunk tubes bell outwards (towards the end of the tubing) during the s

48、hrinking process, briefly apply heat to the inside of the tube to prevent it from turning inside out. 4.4.5 In the case of collapsing cold-shrinkable components that use a helical support core ribbon, carefully unfurl the ribbon turn by turn to avoid interference with the underlying core. Withdraw t

49、he ribbon from within the tubing so that the far end collapses first. 4.4.6 For transition joints to paper-insulated cables, when unwrapping the metallic paper screen from a core, apply one band of adhesive tape around the end of the core (ferrule end) to prevent the paper layers from unwinding later. The adhesive tape will be removed when the conductor is exposed before connecting. 4.4.7 After the application of constant force springs (CFSs) or worm drive clamps, apply tape in order to prevent sharp edges from damaging subsequen