1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS 7870-2:2011LV and MV polymericinsulated cables for use bydistribution and generationutilitiesPart 2: Methods of test(Implementation of HD 605 S2:2008)Publishing and copyright
2、informationThe BSI copyright notice displayed in this document indicates when the documentwas last issued. BSI 2011ISBN 978 0 580 70007 1ICS 29.060.20The following BSI references relate to the work on this standard:Committee reference GEL/20/16Draft for comment 11/30214057 DCPublication historyFirst
3、 published October 1996Second edition, June 1999Third (present) edition, December 2011Amendments issued since publicationDate Text affectedBS 7870-2:2011 BRITISH STANDARDContentsForeword iiiSection 1 General 11.1 Scope 11.2 Normative references 11.3 Applicable tests 11.4 Sampling 11.5 Test condition
4、s 21.6 Rounding of numbers 2Section 2 Non-electrical tests 32.1 Dimensional measurements 32.2 Mechanical tests on non-metallic components 82.3 Mechanical tests on metallic components 112.4 Non-electrical tests on samples of complete cable 112.5 Physical and chemical tests 18Section 3 Electrical test
5、s 203.1 Electrical resistance 203.2 Voltage tests 213.3 Insulation resistance tests 223.4 N/A 243.5 N/A 243.6 Spark tests 243.7 N/A 253.8 Heating cycle test 253.9 Measurement of the electrical resistivity of the semi-conductingscreens 253.10 Partial discharge test 283.11 Tan measurement 293.12 N/A 2
6、93.13 Adherence of screens at short circuit temperature 293.14 Resistivity test for water blocking tape 303.15 N/A 313.16 N/A 313.17 N/A 313.18 N/A 313.19 N/A 31Section 4 N/A 31Section 5 Long-term tests 315.1 N/A 315.2 N/A 315.3 N/A 315.4 Long-term voltage test 315.5 N/A 345.6 N/A 34AnnexesAnnex A (
7、normative) NA 35Annex B (normative) NA 35Bibliography 36List of figuresFigure 2.1.10.5 Dissociation, inclusions and penetration 7Figure 2.2.2.2 Test piece for tear resistance test method 2 9Figure 2.4.5 Abrasion test 13Figure 2.4.9.1 Schematic diagram of apparatus for water penetration test 15Figure
8、 2.5.9 Details of test apparatus to determine the tape swell height 19Figure 3.3.1 Height measurement of insulated sectoral shaped conductors 24BRITISH STANDARD BS 7870-2:2011 BSI 2011 iFigure 3.9.1a) Measurement of the volume resistivity of the conductorscreen 27Figure 3.9.1b) Measurement of the vo
9、lume resistivity of the insulationscreen 28List of tablesTable 1.5.2 Tolerances on temperature values 2Table 2.4.5 Vertical force on cable during abrasion test 14Table 3.11.3.1 Coefficients for correction of tan values to 20 C 29Summary of pagesThis document comprises a front cover, an inside front
10、cover, pages i to iv,pages 1 to 36, an inside back cover and a back cover.BRITISH STANDARDBS 7870-2:2011ii BSI 2011ForewordPublishing informationThis part of BS 7870 is published by BSI and came into effect on31 December 2011. It was prepared by Subcommittee GEL/20/16, Medium/Highvoltage cables, und
11、er the authority of Technical Committee GEL/20, Electriccables. A list of organizations represented on these committees can be obtainedon request to their secretary.SupersessionThis part of BS 7870 supersedes BS 7870-2:1999, which is withdrawn.Relationship with other publicationsBS 7870 implements t
12、he nationally applicable parts of Harmonization DocumentsHD 603, 605, 620, 626 and 627 published by the European Committee forElectrotechnical Standardization (CENELEC), in accordance with the decision ofthe CENELEC Technical Board.BS 7870 applies to cables for fixed installation having rated voltag
13、e U0/U up toand including 19/33 kV, and is published as a series of separate parts andsections, as listed in the table in the foreword of BS 7870-1.This part of BS 7870 implements the nationally applicable parts ofHD 605 S2:2008.BS 7870-2:2011 should be read in conjunction with BS 7870-1:2011 and th
14、eappropropriate parts and sections of BS 7870, a number of which have beenupdated to 2011 editions.Information about this documentThis is a full revision of the standard, which brings the standard up to date inaccordance with current practice in the industry.Clause numbering system. The clause numbe
15、ring system used in this part ofBS 7870 aligns with HD 605 S2:2008 to facilitate cross-referencing, except forSection 1 and the annexes. However, where a particular test is not specified inthe separate parts and sections of BS 7870, the relevant clauses and/orsubclauses are marked “N/A” (not applica
16、ble).Hazard warningsWARNING. This British Standard calls for the use of substances and/orprocedures that can be injurious to health if adequate precautions are nottaken. It refers only to technical suitability and does not absolve the userfrom legal obligations relating to health and safety at any s
17、tage.Use of this documentIt has been assumed in the preparation of this British Standard that theexecution of its provisions will be entrusted to appropriately qualified andexperienced people, for whose use it has been produced.Presentational conventionsThe provisions of this standard are presented
18、in roman (i.e. upright) type. Itsmethods are expressed as a set of instructions, a description, or in sentences inwhich the principal auxiliary verb is “shall”.Commentary, explanation and general informative material is presented insmaller italic type, and does not constitute a normative element.BRI
19、TISH STANDARD BS 7870-2:2011 BSI 2011 iiiContractual and legal considerationsThis publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legalobligations.BRITI
20、SH STANDARDBS 7870-2:2011iv BSI 2011Section 1 General1.1 ScopeBS 7870-2 collates and specifies the test methods to be used for testingpolymeric insulated and sheathed electric cables, of rated voltage up to andincluding 19/33 kV, intended for public distribution systems, and for use inpower generati
21、ng plants and sub-stations.The test methods in this part of BS 7870 are additional to those alreadyharmonized, e.g. in the BS EN 60332 series and the BS EN 60811 series, and arefor use for testing cable types specified in BS 7870-3, BS 7870-4 and BS 7870-5. Ineach case, these standards give compleme
22、ntary information needed for thepractical application of the test method to each specific type of cable. ThereforeBS 7870-2:2011, as such, is not sufficient for carrying out and evaluating thetests on electric cables.Full test conditions (e.g. temperatures, durations) and/or requirements to be metar
23、e not specified in this standard. Such data needed to carry out the tests isgiven in the particular sections of BS 7870.NOTE The words “particular section” refer throughout to the individual sections ofBS 7870 in which particular cable types are specified.1.2 Normative referencesThe following refere
24、nced documents are indispensable for the application ofthis document. For dated references, only the edition cited applies. For undatedreferences, the latest edition of the referenced document (including anyamendments) applies.BS 5099, Electric cables Voltage levels for spark testingBS EN 10244-2:20
25、09, Steel and wire products Non-ferrous metallic coatings onsteel wire Part 2: Zinc or zinc alloy coatingsBS EN 60228, Conductors of insulated cablesBS EN 60230, Impulse tests on cables and their accessoriesBS EN 60811-1-1, Insulating and sheathing materials of electric and opticalcables Common test
26、 methods Part 1-1: General application Measurement ofthickness and overall dimensions Tests for determining the mechanicalpropertiesBS EN 60811-1-2, Insulating and sheathing materials of electric cables Commontest methods Part 1-2: General application Thermal ageing methodsBS EN 60885-3, Electrical
27、test methods for electric cables Part 3: Test methodsfor partial discharge measurements on lengths of extruded power cablesBS EN 62230, Electric cables Spark test methodBS EN ISO 4892 (all parts), Plastics Methods of exposure to laboratory lightsources1.3 Applicable testsTests applicable to each typ
28、e of cable are given in the particular sections which,where applicable, also specify the test sequence, the frequency of testing, andthe possibility of repeating failed tests.1.4 SamplingThe size and number of samples are specified either in this standard or in theparticular section of BS 7870.BRITI
29、SH STANDARD BS 7870-2:2011 BSI 2011 1If a marking is indented in the insulation or sheath surface, the samples used forthe tests shall be taken so as to include such markings.For multicore cables, except for the test specified in 2.1.1, not more than threecores (of different colours, if available) s
30、hall be tested, unless otherwise specifiedfor a particular test.1.5 Test conditions1.5.1 Ambient temperatureUnless otherwise specified in the details for the particular test, tests shall becarried out at an ambient temperature of (20 15) C.1.5.2 Tolerance on temperature valuesUnless otherwise specif
31、ied in the particular section, the tolerances on thetemperature values quoted in the test methods shall be as given in Table 1.5.2.Table 1.5.2 Tolerances on temperature valuesSpecified temperature, tCToleranceK40 t 020 150 31.5.3 Frequency and waveform of power-frequency test voltagesUnless otherwis
32、e specified in the details for the particular test, the test voltageshall be in the range 49 Hz to 61 Hz, of approximately sine-wave form, the peakratio value/r.m.s. value being equal to2 with a tolerance of 7%. The valuesgiven are r.m.s.1.5.4 Pre-conditioningUnless otherwise specified in the detail
33、s for the particular test, the tests shall becarried out not less than 16 h after the extrusion or cross-linking, if any, of theinsulating or sheathing compounds.1.6 Rounding of numbersIt may be required that values are rounded to one or more decimal places. Thismay occur, for instance, in calculati
34、ng the average value of several measurementresults, or the minimum value by applying a percentage tolerance to a givennominal value. In these cases, rounding shall be carried out to the number ofdecimal places specified in the relevant clauses. The method of rounding shallthen be as follows:a) if th
35、e last figure to be retained is followed, before rounding, by 0, 1, 2, 3or 4, it shall remain unchanged (rounding down);b) if the last figure to be retained is followed, before rounding, by 9, 8, 7, 6or 5, it shall be increased by one (rounding up).EXAMPLES:2.449 2.45 rounded to two decimal places2.
36、449 2.4 rounded to one decimal place25.0478 25.048 rounded to three decimal places25.0478 25.05 rounded to two decimal places25.0478 25.0 rounded to one decimal placeBRITISH STANDARDBS 7870-2:20112 BSI 2011Section 2 Non-electrical tests2.1 Dimensional measurements2.1.1 Measurement of insulation thic
37、kness2.1.1.1 ProcedureThe thickness of the insulation shall be measured in accordance withBS EN 60811-1-1, 8.1. Unless otherwise specified, one sample of cable shall betaken and measurements made at three places.Conformity shall be checked on each core of cables having up to five cores, andon the nu
38、mber of cores stated in the particular section for cables with morethan five cores.If withdrawal of the conductor is difficult, it shall be stretched in a tensiletesting machine, or the piece of core shall be immersed in an appropriate liquiduntil the insulation becomes loose.2.1.1.2 Evaluation of r
39、esultsUnless otherwise specified, the mean of the 18 values (expressed in millimetres)obtained from the three pieces of insulation from each core shall be calculatedto two decimal places and rounded up or down as given below, and this shall betaken as the mean value of the thickness of the insulatio
40、n.If in the calculation the second decimal figure is 5 or more, the first decimalfigure shall be raised to the next number; thus, for example, 1.74 shall berounded to 1.7 and 1.75 to 1.8.The lowest of all the values obtained shall be taken as the minimum thickness ofthe insulation at any place.2.1.2
41、 Measurement of non-metallic sheath thickness2.1.2.1 ProcedureThe thickness of the sheath shall be measured in accordance withBS EN 60811-1-1, 8.2. Unless otherwise specified, one sample of cable shall betaken and measurements made at three places.2.1.2.2 Evaluation of resultsThe mean of all the val
42、ues (expressed in millimetres) obtained from the threepieces of sheath shall be calculated to two decimal places and rounded up ordown as given below, and this shall be taken as the mean value of the thicknessof the sheath.If in the calculation the second decimal figure is 5 or more, the first decim
43、alfigure shall be raised to the next number; thus, for example, 1.74 shall berounded to 1.7 and 1.75 to 1.8.The lowest of all the values obtained shall be taken as the minimum thickness ofthe sheath at any place.2.1.3 Measurement of cable dimensions2.1.3.1 Measurement of overall dimensionsUnless oth
44、erwise specified, the three samples taken in accordance with 2.1.1or 2.1.2 shall be used.The measurement of the overall diameter of any circular cable and of theoverall dimensions of flat cables with a major dimension not exceeding 15 mmshall be carried out in accordance with BS EN 60811-1-1, 8.3.BR
45、ITISH STANDARD BS 7870-2:2011 BSI 2011 3For the measurement of flat cables with a major dimension exceeding 15 mm, amicrometer, a profile projector or similar equipment shall be used.The mean of the values obtained shall be taken as the mean overall dimensions.2.1.3.2 Measurement of ovalityFor check
46、ing the ovality of circular sheathed cables, two measurements shall bemade at the same cross-section of the cable, covering the maximum andminimum values.2.1.4 Measurement of wires, strips and tapes2.1.4.1 N/A2.1.4.2 N/A2.1.4.3 Wires, strips and tapes from armourMeasurement of wires, strips and tape
47、s from armour shall be carried out asfollows.a) Round wiresTake at random 10 wires or 10% of the total number of wires, whichever is thelesser, from a sample of the completed cable.Determine the diameter of each wire in this sample of wires by taking twomeasurements at right angles to each other usi
48、ng a micrometer with flat nosesto an accuracy of 0.01 mm.Take the average value as the wire diameter.b) Flat wires or stripsTake at random 10 flat wires or strips or 10% of the total number of flat wiresor strips, whichever is the lesser, from a sample of the completed cable.Determine the thickness
49、and width of each flat wire or strip in this sample offlat wires or strips by using either a micrometer with flat noses to an accuracy of0.01 mm or a vernier calliper with flat noses to an accuracy of 0.02 mm.Take the average values as the wire or strip thickness and wire or strip width.c) Metallic tapes thicknessTake and straighten a sample of each armour tape, remove the non-metalliccoating, if any, and determine the tape thickness at six different places.The measurement shall be made with eithe
