BS EN 61395-1998 Overhead electrical conductors - Creep test procedures for stranded conductors《架空电力导线 多股导线蠕变试验程序》.pdf

1、BRITISH STANDARD BS EN 61395:1998 IEC 61395: 1998 Overhead electrical conductors Creep test procedures for stranded conductors The European Standard EN 61395:1998 has the status of a British Standard ICS 29.240.20BSEN61395:1998 This British Standard, having been prepared under the direction of the E

2、lectrotechnical Sector Board, was published under the authority of the Standards Board and comes into effect on 15 September 1998 BSI 04-1999 ISBN 0 580 30140 0 National foreword This British Standard is the English language version of EN 61395:1998. It is identical with IEC 61395:1998. The UK parti

3、cipation 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

4、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

5、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-references Attention is drawn to the fact that CEN and CENELEC standards nor

6、mally 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 sectio

7、n 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. C

8、ompliance 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, theEN title page, pages 2 to 8, an inside back cover and a back cover. This standard has been updated (see copyr

9、ight date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date CommentsBSEN61395:1998 BSI 04-1999 i Contents Page National foreword Inside front cover Foreword 2 Text of EN 61395 3ii blan

10、kEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 61395 April 1998 ICS 29.240.20 Descriptors: Overhead electrical line, electrical conductor, aluminium, aluminium alloy, definition, sample, preparation, selection, creep test, measurement, creep temperature English version Overhead electrical con

11、ductors Creep test procedures for stranded conductors (IEC 61395:1998) Conducteurs pour lignes lectriques ariennes Procdures dessai de fluage pour conducteurs cbls (CEI 61395:1998) Leiter fr elektrische Freileitungen Kriechprfungen fr verseilte Leiter (IEC 61395:1998) This European Standard was appr

12、oved 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 nati

13、onal 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 languag

14、e 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, Spa

15、in, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1998 CENELEC All rights of exploitatio

16、n in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61395:1998 EEN61395:1998 BSI 04-1999 2 Foreword The text of document 7/515/FDIS, future edition 1 of IEC 61395, prepared by IEC TC 7, Overhead electrical conductors, was submitted to the IEC-CENELEC parallel vote and

17、was approved by CENELEC as EN 61395 on 1998-04-01. The following dates were fixed: Annexes 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 and Annex A is informative. Annex ZA has be

18、en added by CENELEC. Endorsement notice The text of the International Standard IEC 61395:1998 was approved by CENELEC as a European Standard without any modification. Contents Page Foreword 2 1 Scope 3 2 Normative reference 3 3 Definitions 3 4 Units, instrumentation and calibration 3 5 Sample select

19、ion and preparation 3 5.1 Sample selection 3 5.2 Sample preparation 4 6 Temperature and temperature variations 4 6.1 Temperature variations 4 6.2 Accuracy of temperature measuring devices 4 6.3 Temperature compensation 5 7 Load 5 7.1 Test load 5 7.2 Strain measurement 5 8 Test procedure 5 9 Data acq

20、uisition 5 10 Data interpretation 6 Annex A (informative) Practice 7 Annex ZA (normative) Normative references to international publications with their corresponding European publications Inside back cover Figure 1 Typical creep test arrangement 4 latest date by which the ENhas to be implemented at

21、national level by publication of an identical national standard or by endorsement (dop) 1999-01-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2001-01-01EN61395:1998 BSI 04-1999 3 1 Scope This International Standard is primarily applicable to non-in

22、terrupted 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

23、 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 reference The following normative document contains provi

24、sions 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

25、 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 Definitions For the purpose of th

26、is International Standard, the following definitions apply. 3.1 sample length total length of the conductor between the end fittings 3.2 gauge length distance of the conductor over which the creep is measured 3.3 test temperature mean temperature taken at the three pre-specified positions along the

27、gauge length or, when more than three measuring positions are used, the mean temperature taken at equal distances along the gauge length 3.4 test load constant load acting on the conductor during the test NOTEThis causes the permanent time dependent elongation known as creep. 3.5 loading time time r

28、equired either from preload when preload is applied to test load or from no load to test load 3.6 duration of test time span between reaching test load and the end of the test 3.7 creep test machine complete equipment by means of which the conductor sample is tensioned during the test 3.8 end fittin

29、g hardware that maintains the electrical and/or the mechanical continuity of the conductor 4 Units, instrumentation and calibration Units 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 s

30、hall 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 preparation 5.1 Sample selection The sample shall be taken at least 20m from the end of the co

31、nductor 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 a where 100 d i

32、s the minimum gauge length; d is the conductor diameter; a is the distance between the end fitting and the gauge length. a a These minimum specifications are only correct when the ends are placed in resin.EN61395:1998 4 BSI 04-1999 The distance, a, shall be at least 25% of the gauge length or 2m whi

33、chever 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

34、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 b

35、e used as the sample length. b) When recoiling for transportation, a coil diameter of1,5m minimum shall be used. 5.2 Sample preparation End 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

36、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 variations The conductor temperature sha

37、ll 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 2

38、0C. 6.1 Temperature variations Conductor temperature variation along the gauge length shall be less than 2,0C. Conductor temperature variation during the test shall be less than 2,0C. It is important to ensure that greater deviations than those stated above do not take place. A means of continuously

39、 monitoring the air or conductor temperature is recommended. 6.2 Accuracy of temperature measuring devices The accuracy of the equipment used for temperature measurements shall be within 0,5C. The accuracy of the temperature measuring device used on the gauge length shall be clearly stated in the te

40、st report. The method used for temperature control and measurement shall also be fully documented. Figure 1 Typical creep test arrangementEN61395:1998 BSI 04-1999 5 6.3 Temperature compensation Temperature variations shall be compensated, either by using a thermal reference with the same coefficient

41、 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,

42、5C. 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 Load 7.1 Test load The a

43、ccuracy of the test load shall be within 1% or 120N whichever is the greater. Load cells shall be used during the test. 7.2 Strain measurement The accuracy and the set up of the strain measuring device shall be sufficient to determine the conductor sample strain to the nearest5 10 6 . The measuring

44、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 procedure The sample prepared in accordance wi

45、th the procedure described in clause5 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 b

46、e avoided in order not to influence the shape of the creep curve. Usually not more than 5min at preload can be accepted. The loading time shall be 5min 10s. 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

47、 be greater than 20% of the test load 1) . When step loading is utilised, care should be taken to ensure that the area under the load 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 durati

48、on of the test. 2) 9 Data acquisition Creep and conductor temperature measurements shall be taken from the moment the full load is applied, i.e. at the end of the 5min allowed for the loading time. Thereafter, conductor temperature and readings to calculate the creep elongations shall be evenly spac

49、ed on the logarithmic time scale 3) . 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 and creep. The second reading, which is the first value of the creep, shall be taken not later than0,02h 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 at least 1000h, which would pred