【BS英国标准】BS EN 61395-1998 多股导线的蠕变试验程序.doc

licensed copy: institute of technology tallaght, institute of technology, fri mar 23 04:17:31 gmt+00:00 2007, uncontrolled copy, (c) bsibritish standard bs en61395:1998iec 61395:1998overhead electrical conductors creep test procedures for stranded conductorsthe european standard en 61395:1998 has the status of abritish standardics 29.240.20bs en 61395:1998national forewordthis british standard is the english language version of en 61395:1998. it is identical with iec 61395:1998.the uk participation in its preparation was entrusted to technical committee gel/7, wrought aluminium for electrical purposes, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/european committee any enquiries on the interpretation, or proposals for change, and keep the uk interests informed; monitor related international and european developments and promulgate them in the uk.a list of organizations represented on this committee can be obtained on request to its secretary.from 1 january 1997, all iec publications have the number 60000 added to the old number. for instance, iec 27-1 has been renumbered as iec 60027-1. for a period of time during the change over from one numbering system to the other, publications may contain identifiers from both systems.cross-referencesattention is drawn to the fact that cen and cenelec standards normally include an annex which lists normative references to international publications with their corresponding european publications. the british standards which implement international or european publications referred to in this document may be found in the bsi standards catalogue under the section entitled “international standards correspondence index”, or by using the “find” facility of the bsi standards electronic catalogue.a british standard does not purport to include all the necessary provisions of a contract. users of british standards are responsible for their correct application.compliance with a british standard does not of itself confer immunity from legal obligations.summary of pagesthis document comprises a front cover, an inside front cover, pages i and ii, the en title page, pages 2 to 8, an inside back cover and a back cover.this standard has been updated (see copyright date) and may have had amendments incorporated. this will be indicated in the amendment table on the inside front cover.licensed copy: institute of technology tallaght, institute of technology, fri mar 23 04:17:31 gmt+00:00 2007, uncontrolled copy, (c) bsiamd. no.datecommentsthis british standard, having been prepared under the direction of the electrotechnical sector board, was published under the authority of the standards board and comesinto effect on15 september 1998 bsi 04-1999isbn 0 580 30140 0amendments issued since publicationlicensed copy: institute of technology tallaght, institute of technology, fri mar 23 04:17:31 gmt+00:00 2007, uncontrolled copy, (c) bsibs en 61395:1998contentspage national forewordinside front cover foreword2text of en 613953 bsi 04-1999iiiblanklicensed copy: institute of technology tallaght, institute of technology, fri mar 23 04:17:31 gmt+00:00 2007, uncontrolled copy, (c) bsieuropean standard norme europenneeuropische normen 61395april 1998ics 29.240.20descriptors: overhead electrical line, electrical conductor, aluminium, aluminium alloy, definition, sample, preparation, selection, creep test, measurement, creep temperatureenglish versionoverhead electrical conductorscreep test procedures for stranded conductors(iec 61395:1998)conducteurs pour lignes lectriquesariennes procdures dessai de fluage pour conducteurs cbls(cei 61395:1998)leiter fr elektrische freileitungen kriechprfungen fr verseilte leiter (iec 61395:1998)licensed copy: institute of technology tallaght, institute of technology, fri mar 23 04:17:31 gmt+00:00 2007, uncontrolled copy, (c) bsithis european standard was approved by cenelec on 1998-04-01. cenelec members are bound to comply with the cen/cenelec internal regulations which stipulate the conditions for giving this european standard the status of a national standard without any alteration.up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the central secretariat or to any cenelec member.this european standard exists in three official versions (english, french, german). a version in any other language made by translation under the responsibility of a cenelec member into its own language and notified to the central secretariat has the same status as the official versions.cenelec members are the national electrotechnical committees of austria, belgium, czech republic, denmark, finland, france, germany, greece, iceland, ireland, italy, luxembourg, netherlands, norway, portugal, spain, sweden, switzerland and united kingdom.ceneleceuropean committee for electrotechnical standardization comit europen de normalisation electrotechnique europisches komitee fr elektrotechnische normungcentral secretariat: rue de stassart 35, b-1050 brussels 1998 cenelec all rights of exploitation in any form and by any means reserved worldwide forcenelec members.ref. no. en 61395:1998 een 61395:19987 bsi 04-1999licensed copy: institute of technology tallaght, institute of technology, fri mar 23 04:17:31 gmt+00:00 2007, uncontrolled copy, (c) bsiforewordthe text of document 7/515/fdis, future edition 1 of iec 61395, prepared by iec tc 7, overhead electrical conductors, was submitted to theiec-cenelec parallel vote and was approved bycenelec as en 61395 on 1998-04-01.the following dates were fixed: latest date by which the en has to be implemented at national level by publication of an identical national standard or byendorsement(dop) 1999-01-01 latest date by which the national standards conflicting with the enhave to be withdrawn(dow) 2001-01-01annexes designated “normative” are part of the body of the standard.annexes designated “informative” are given for information only.in this standard, annex za is normative andannex a is informative.annex za has been added by cenelec.endorsement noticethe text of the international standardiec 61395:1998 was approved by cenelec as aeuropean standard without any modification.contentspage1scope32normative reference33definitions34units, instrumentation and calibration35sample selection and preparation35.1sample selection35.2sample preparation46temperature and temperature variations46.1temperature variations46.2accuracy of temperature measuring devices46.3temperature compensation57load57.1test load57.2strain measurement58test procedure59data acquisition510data interpretation6foreword2annex a (informative) practice7annex za (normative) normative references to international publications with their corresponding europeanpublicationsinside back coverfigure 1 typical creep testarrangement4licensed copy: institute of technology tallaght, institute of technology, fri mar 23 04:17:31 gmt+00:00 2007, uncontrolled copy, (c) bsi1 scopethis international standard is primarily applicable to non-interrupted creep-testing of stranded conductors for overhead lines such as those specified by iec 61089. procedures for interpreting the results are also included.the object of the test is principally to calculate creep for any purpose and to compare creep of different conductors.the requirement of this standard aims at an accuracy of 1 %. however, it should be recognized that due to variations occurring in the manufacturing process, the creep obtained in the test is not a precise value for all conductors of the type tested.2 normative referencethe following normative document contains provisions which, through reference in this text, constitute provisions of this international standard. at the time of publication, the edition indicated was valid. all normative documents are subject to revision, and parties to agreements made on this international standard are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below. members of iec and iso maintain registers of currently valid international standards.iec 61089:1991, round wire concentric lay overhead electrical stranded conductors.3 definitionsfor the purpose of this international standard, the following definitions apply.3.1sample lengthtotal length of the conductor between the end fittings3.2gauge lengthdistance of the conductor over which the creep is measured3.3test temperaturemean temperature taken at the three pre-specified positions along the gauge length or, when more than three measuring positions are used, the mean temperature taken at equal distances along the gauge length3.4test loadconstant load acting on the conductor during the testnote this causes the permanent time dependent elongation known as creep.3.5loading timetime required either from preload when preload is applied to test load or from no load to test load3.6duration of testtime span between reaching test load and the end of the test3.7creep test machinecomplete equipment by means of which the conductor sample is tensioned during the test3.8end fittinghardware that maintains the electrical and/or the mechanical continuity of the conductor4 units, instrumentation and calibrationunits of the international system of units(si-units) shall be used.to ensure traceable accuracy of the test, calibration records of all instruments used in the test shall be kept. the equipment shall be calibrated in accordance with nationally recognized standards. where no such standards exist, the basis used for calibration shall be documented.5 sample selection and preparation5.1 sample selectionthe sample shall be taken at least 20 m from the end of the conductor on the drum. it shall be undamaged during removal and preparation. at least three strong hoseclips shall be placed on both ends of the sample to prevent interlayer movement, before it is cut from the drum.the minimum sample length between the end fittings shall be:100 d + 2 awhere100 d is the minimum gauge length;dis the conductor diameter;ais the distance between the end fitting and the gauge length.aa these minimum specifications are only correct when the ends are placed in resin.figure 1 typical creep test arrangementlicensed copy: institute of technology tallaght, institute of technology, fri mar 23 04:17:31 gmt+00:00 2007, uncontrolled copy, (c) bsithe distance, a, shall be at least 25 % of the gauge length or 2 m whichever is the smaller. the total length cut from the conductor shall include the necessary length to provide for the grips at the two ends of the sample. figure 1 shows a typical set-up.the sample and the gauge lengths have been chosen with due weight being given to the greater accuracy with which creep tests are conducted in comparison with tensile tests.once the sample has been taken from the drum, it shall be kept as straight as possible. if this is impractical the following procedure shall be adopted.a) twice the sample length shall be removed from the drum, and the central part shall be used as the sample length.b) when recoiling for transportation, a coil diameter of 1,5 m minimum shall be used.5.2 sample preparationend fittings, such as low melting point metals and resin bonding etc., attached to test samples shall not allow slippage or interlayer movement.these end fittings shall be installed when the strands of the conductor are concentric. where grease is applied to the conductor, the part of the conductor which is held in the grips shall be degreased prior to the installation of the end fittings.6 temperature and temperature variationsthe conductor temperature shall be measured in the middle and at both ends of the gauge length, during the test. the measuring devices shall be in good contact with the conductor sample and be insulated against the effects of air movements outside the conductor. if not otherwise specified, the temperature of the test shall be 20 c.6.1 temperature variationsconductor temperature variation along the gauge length shall be less than 2,0 c. conductor temperature variation during the test shall be less than 2,0 c. it is important to ensure that greater deviations than those stated above do not take place. a means of continuously monitoring the air or conductor temperature is recommended.6.2 accuracy of temperature measuring devicesthe accuracy of the equipment used for temperature measurements shall be within 0,5 c. the accuracy of the temperature measuring device used on the gauge length shall be clearly stated in the test report. the method used for temperature control and measurement shall also be fully documented.6.3 temperature compensationtemperature variations shall be compensated, either by using a thermal reference with the same coefficient of thermal expansion as the sample, called reference bars in figure 1, or by using a thermocouple reference. in the latter case, the strain variation is calculated and subtracted from the elongation measurements. three temperature measuring devices are used, the accuracy of which shall be within 0,5 c. it shall be clearly understood that the temperature compensation is to reduce the scatter in the measurement arising from the length change of the conductor sample due to thermal elongation only. the effect of temperature change on the creep rate cannot be compensated.7 load7.1 test loadthe accuracy of the test load shall be within 1 % or 120 n whichever is the greater. load cells shall be used during the test.7.2 strain measurementthe accuracy and the set up of the strain measuring device shall be sufficient to determine the conductor sample strain to the nearest 5 106. themeasuring devices may be of any suitable type such as micrometer dial gauges, low voltage displacement transducers or optical systems. uncontrolled rotation during the test, especially of long samples may take place and shall be avoided or compensated for.8 test procedurethe sample prepared in accordance with the procedure described in clause 5 shall be placed in the creep test machine. some machines may require a preload in order to attach the strain measuring devices. in such cases a preload of up to 2 % of the rated tensile strength of the conductor may be allowed. prolonged period at preload shall be avoided in order not to influence the shape of the creep curve. usually not more than 5 min at preload can be accepted.the loading time shall be 5 min 10 s. the loading should be applied evenly up to the test load, without overload. where it is necessary to load in steps, incremental steps shall not be greater than 20 % of the test load1). when step loading is utilised, careshould be taken to ensure that the area under theload graph (in a stress versus time diagram) equals that of the straight line from preload or zero load to the test load. the load shall be kept constant during the duration of the test.2)9 data acquisitioncreep and conductor temperature measurements shall be taken from the moment the full load is applied, i.e. at the end of the 5 min allowed for the loading time. thereafter, conductor temperature and readings to calculate the creep elongations shallbe evenly spaced on the logarithmic time scale3). the number of these readings shall be at least three in each interval, with ten times increase of the time. the first reading corresponds to zero time andcreep. the second reading, which is the first value ofthe creep, shall be taken not later than 0,02 h after the first reading. when a thermocouple reference is used for the temperature compensation, readings of elongation and temperature shall be made at the same moment. the duration of the test shall be atleast 1 000 h, which would predict the long timecreep sufficiently accurately.most of the creep data available are basedon 1 000 h creep tests. longer times give greater accuracy, but due to the logarithmic presentation, very long times are needed to increase the effectsignificantly. it is recognized that due to theunmeasured creep at the beginning of the test, the curvature will result in lower time creep the longer the test continues.licensed copy: institute of technology tallaght, institute of technology, fri mar 23 04:17:31 gmt+00:00 2007, uncontrolled copy, (c) bsi1) this procedure has been chosen so that all samples experience the same amount of creep time before the measurement commences.2) vibration if not isolated can affect results.3) other readings can be taken but should not be included in the calculation.10 data interpretationwhen the conductor elongates according to power law creep, the creep measured for each equal time interval on the logarithmi