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1、BRITISH STANDARD BS 7888-2:1998 Incorporating Amendment No. 1 LV and MV accessories for power cables with rated voltage from 0.6/1 kV (Um = 1.2 kV) up to and including 20.8/36 kV (Um= 42 kV) Part 2: Methods of test (Implementation of parts of HD 623 and 628) ICS 29.060.20; 29.120.20 ? Licensed Copy:
2、 London South Bank University, London South Bank University, Fri Dec 08 12:11:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7888-2:1998 This British Standard, having been prepared under the direction of the Electrotechnical Sector Board, was published under the authority of the Standards Board an
3、d comes into effect on 15 March 1998 BSI 2 May 2003 The following BSI references relate to the work on this standard: Committee reference GEL/20/11 Draft for comment 92/26317 DC ISBN 0 580 29501 X Committees responsible for this British Standard The preparation of this British Standard was entrusted
4、 by Technical Committee GEL/20, Electric cables, to Technical Subcommittee GEL/20/11 (formerly GEL/20/7), Cable accessories, upon which the following bodies were represented: Association of Consulting Engineers BEAMA Electrical Cable and Conductor Accessory Manufacturers Association British Approval
5、s Service for Cables British Cables Association Electrical Installation Equipment Manufacturers Association (BEAMA Ltd.) Electricity Association ERA Technology Ltd. Institution of Lighting Engineers London Underground Ltd. Railway Industries Association Amendments issued since publication Amd. No.Da
6、teComments 138972 May 2003Revision of 12.3 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:11:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7888-2:1998 BSI 2 May 2003 i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2Normative re
7、ferences1 3Terms and definitions2 4Test installations and conditions2 5A.C. voltage withstand test2 6D.C. voltage withstand test3 7Impulse voltage withstand test3 8Partial discharge test3 9Thermal cycling test4 10Thermal short-circuit test (metallic screen)5 11Thermal short-circuit test (conductor)6
8、 12Dynamic short-circuit test6 13Humidity and salt fog tests7 14Impact test at ambient temperature8 15Insulation resistance test10 16Immersion test10 17Examination10 Annex A (normative) Tests at elevated temperature12 Annex B (informative) Determination of cable conductor temperature15 Annex C (info
9、rmative) Details of test chamber and spray equipment for humidity and salt fog tests19 Bibliography21 Figure 1 Thermal cycle5 Figure 2 General arrangement for the impact tests (at ambient temperature)9 Figure A.1 Terminations tested in air12 Figure A.2 Joints tested in air13 Figure A.3 Joints tested
10、 under water13 Figure A.4 Outdoor terminations tested under water (LV terminations: BS 7888-3)14 Figure A.5 Outdoor terminations tested under water (MV terminations: BS 7888-4.1 and BS 7888-4.2)14 Figure B.1 Reference cable16 Figure B.2 Arrangement of the thermocouples16 Figure B.3 Current/temperatu
11、re curves18 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:11:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7888-2:1998 ii BSI 2 May 2003 Foreword BS 7888 was prepared by Technical Subcommittee GEL/20/11. It implements the nationally applicable parts of H
12、armonization Documents HD 623, 628, 629.1 and 629.2, published by the European Committee for Electrotechnical Standardization (CENELEC) in accordance with the decision of the CENELEC Technical Board. BS 7888 applies to accessories for power cables with rated voltage U0/U from 0.6/1 kV (Um= 1.2 kV) u
13、p to and including 20.8/36 kV (Um= 42 kV) and is published as a series of separate parts and sections, as listed in the table in the Foreword of BS 7888-1. BS 7888-2 implements the relevant tests of HD 623 and HD 628 and is to be read in conjunction with BS 7888-1. It has been assumed in the prepara
14、tion of this British Standard that the execution of its provisions will be entrusted to appropriately qualified and experienced people, for whose use it has been produced. WARNING. The methods of test described in this British Standard do not detail all precautions necessary to meet the requirements
15、 of the Health and Safety at Work etc. Act 1974. Attention should be paid to any appropriate safety precautions and the tests should only be performed by authorized personnel. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its corre
16、ct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 21 and a back cover. The BSI copyright notice displayed in this document indicates w
17、hen the document was last issued. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:11:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7888-2:1998 BSI 2 May 2003 1 1 Scope BS 7888-2 collates and specifies the test methods to be used for type testing accessorie
18、s for power cables with rated voltage from 0.6/1 (1.2) kV up to and including 20.8/36 (42) kV. Test methods are specified for accessories for polymeric cables in accordance with BS 7870-3 and BS 7870-4, and paper cables in accordance with BS 7894. Full test conditions (e.g. temperatures, durations)
19、and/or test requirements are not specified in this part of BS 7888. Such data needed to perform the tests is given in BS 7888-3 LV 0.6/1 (1.2) kV and BS 7888-4 MV 3.6/6 (7.2) kV to 20.8/36 (42) kV. Tests applicable to each type of accessory are given in the particular part or section, which state al
20、so the sequence of testing and the details for conformity. 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 document (in
21、cluding any amendments) applies. BS 923-1:1990, Guide on high-voltage testing techniques Part 1: General. BS 4828:1985, Guide for partial discharge measurements. BS 7454:1991, Method for calculation of thermally permissible short-circuit currents, taking into account non-adiabatic heating effects. B
22、S 7870-3:2001 (all sections), LV and MV polymeric insulated cables for use by distribution and generation utilities Part 3: Specification for distribution cables of rated voltage 0.6/1 kV. BS 7870-4:1999 (all sections), LV and MV polymeric insulated cables for use by distribution and generation util
23、ities Part 4: Specification for distribution cables with extruded insulation for rated voltages from 11 kV and 3 kV. BS 7888-1:1998, LV and MV accessories for power cables with rated voltage from 0.6/1 kV (Um= 1.2 kV) up to and including 20.8/36 kV (Um= 42 kV) Part 1: General. BS 7888-3:1998, LV and
24、 MV accessories for power cables with rated voltage from 0.6/1 kV (Um= 1.2 kV) up to and including 20.8/36 kV (Um= 42 kV) Part 3: Test requirements for LV accessories. BS 7888-4.1:1998, Test requirements for MV accessories Part 4.1: Accessories for cable with extruded insulation. BS 7888-4.2:1998, T
25、est requirements for MV accessories Part 4.2: Accessories for cable with impregnated paper insulation. HD 48, Impulse tests on cables and their accessories (Implements IEC 60230). HD 621, Medium voltage impregnated paper insulated distribution cables . HD 6231), Specification for joints, stop ends a
26、nd outdoor terminations for distribution cables of rated voltage 0.6/1 kV. HD 6281), Test methods for accessories for power cables with rated voltage from 3.6/6 kV (Um= 7.2 kV) up to and including 20.8/36 kV (Um= 42 kV) HD 629-11), Test requirements and accessories for use on power cables of rated v
27、oltage from 3.6/6 (7.2) kV up to 20.8/36 (42) kV Part 1: Cables with extruded insulation. HD 629-21), Test requirements and accessories for use on power cables of rated voltage from 3.6/6 (7.2) kV up to 20.8/36 (42) kV Part 2: Cables with impregnated paper insulation. IEC 60885-2, Electrical test me
28、thods for electric cables Part 2: Partial discharge tests. IEC 60986, Short-circuit temperature limits of electric cables with rated voltages from 6 kV (Um= 7.2 kV) up to 30 kV (Um= 36 kV). 1)Referred to in the foreword only. Licensed Copy: London South Bank University, London South Bank University,
29、 Fri Dec 08 12:11:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7888-2:1998 2 BSI 2 May 2003 3 Terms and definitions For the purposes of this part of BS 7888, the definitions given in Clause 3 of BS 7888-1:1998 apply. 4 Test installations and conditions 4.1 The test methods described in this stan
30、dard are intended to be used for type tests. 4.2 The arrangement and number of test samples are given in the relevant standard. 4.3 The test conditions are specified in Clauses 5 to 17 of this standard. When not, they shall be as specified in the relevant standards. 4.4 Unless otherwise stated, the
31、testing parameters and the requirements are specified in the relevant standard. 4.5 For transition joints (either polymeric to polymeric or polymeric to paper), the testing parameters (voltage and conductor temperature) are those of the lower rated cable. 4.6 The tests shall be started not less than
32、 24 h after installation of the accessories on the cable test loops, unless otherwise specified by the manufacturer. The time interval shall be recorded in the test report. 4.7 Cable screens and armour, if any, shall be bonded and earthed at one end only to prevent circulating currents. 4.8 All part
33、s of an accessory which are normally earthed shall be connected to the cable screen. Any supporting metalwork shall also be earthed. 4.9 The ambient temperature shall be (20 15) C. 5 A.C. voltage withstand test 5.1 Installation The test shall be performed on joints and stop ends while immersed in th
34、e water tank (or pressure vessel) with a height of water of () m or equivalent pressure up to a maximum of 0.5 bar2), or air. The test shall be performed on terminations in a vertical position, unless they are to be specifically installed in another orientation, with the relative spacing as under se
35、rvice conditions, in accordance with the manufacturers instructions. 5.2 Method The procedure for voltage application, including for LV, shall be as specified in 17.1 of BS 923-1:1990, at ambient temperature. 5.3 Single-phase test Apply the voltage between the bunched phase cores and all other metal
36、lic parts and the water (if appropriate). Apply the voltage to each phase core in turn with all other phase cores, metallic parts and water earthed. NOTEWhere the neutral is insulated from the water, the neutral shall be treated as another phase core for the purposes of this test. 5.4 Three-phase te
37、st Three-phase testing applies only to non-radial field MV accessories, and a three-phase or three single-phase transformers shall be used to energize the accessories under test. Single-phase transformers shall be star connected with the neutral point earthed. 5.5 Dry test The set(s) of accessories
38、shall be erected with all associated metalwork and fittings. The accessories shall be clean and dry before applying the test voltage. 2)1 bar = 105 N/m2= 100 kPa. 1.00 0 +0.02 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:11:30 GMT+00:00 2006, Uncontrolled
39、Copy, (c) BSI BS 7888-2:1998 BSI 2 May 2003 3 5.6 Wet test: spray The wet test method, including for LV, shall be as specified in 9.1 of BS 923-1:1990, at ambient temperature. 6 D.C. voltage withstand test 6.1 Installation The set(s) of accessories shall be erected with all associated metalwork and
40、fittings. The accessories shall be clean and dry before applying the test voltage. 6.2 Method A voltage of negative polarity shall be applied to the cable conductor. The test shall be made at ambient temperature, and the procedure for voltage application shall be as specified in 14.1 of BS 923-1:199
41、0. 7 Impulse voltage withstand test 7.1 Installation For preparation of the test installation, involving metal enclosures and terminal boxes, reference shall be made to the relevant standard. In the case of three-core accessories (or three single-core terminations in an enclosure), one phase shall b
42、e tested at a time with the other two phases earthed. 7.2 Method The test shall be conducted in accordance with HD 48. 7.3 Test at elevated temperature Installation and the measurement of temperature are given in Annex A and Annex B respectively. Before and during the impulse test, the cable conduct
43、or shall be heated and stabilized for at least 2 h at a temperature of either: for extruded insulation cables, 5 K to 10 K above the maximum cable conductor temperature in normal operation given in BS 7870-4; or for paper insulated cables, 0 K to 5 K above the maximum cable conductor temperature in
44、normal operation given in HD 621. 8 Partial discharge test 8.1 Applicability This test is only required for accessories for extruded insulation single-core cables and three-core cables with individually semiconducting screened cores. It is not required for accessories incorporating paper insulated c
45、ables. 8.2 Method The test shall be conducted in accordance with BS 4828 and IEC 60885-2. The partial discharge shall be measured at the test voltage given in BS 7888-4.1. 8.3 Test at elevated temperature Installation and the measurement of temperature are given in Annex A and Annex B respectively.
46、Before and during the partial discharge test the cable conductor shall be heated and stabilized for at least 2 h at a temperature of 5 K to 10 K above the maximum cable conductor temperature in normal operation given in BS 7870-4. Licensed Copy: London South Bank University, London South Bank Univer
47、sity, Fri Dec 08 12:11:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7888-2:1998 4 BSI 2 May 2003 9 Thermal cycling test 9.1 Installation The arrangements for tests in air or water shall be as given in Annex A. For thermal cycling in water, the accessory shall be installed in a water tank (or pre
48、ssure vessel) with a height of water of () m (or equivalent pressure up to a maximum of 0.5 bar). 9.2 Method In respect of the number of cycles and applied voltage, accessories shall be subjected to thermal cycling in accordance with the requirements given in BS 7888-3 or BS 78884 of BS 7888, as app
49、ropriate. The method of measuring temperatures is given in Annex B. The thermal cycle in air or water shall be of 8 h duration with at least 2 h at a steady temperature of either: for extruded insulation cables, 5 K to 10 K above the maximum cable conductor temperature in normal operation given in BS 7870-3 or BS 7870-4 as appropriate; or for paper insulated cables, 0 K to 5 K above the maximum cable cond-uctor temperature in normal operation given in
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