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1、AS 37681990 Australian Standard Guide to the effects of temperature on electrical equipment Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 05 Feb 2009 This Australian Standard was prepared by Committees EL/6, Industrial Switchgear and Controlgear, and EL/7, Power Switchgear. It was approved on behalf
2、of the Council of Standards Australia on 9 January 1990 and published on 16 July 1990. The following interests are represented on Committees EL/6 and EL/7: AustralianBritish Chamber of Commerce Australian Electrical and Electronic Manufacturers Association Bureau of Steel Manufacturers of Australia
3、Confederation of Australian Industry Electricity Contractors Association of Australia Independent Electrical Switchboard Manufacturers Association Institution of Engineers, Australia Railways of Australia Committee Testing Authorities Water Board, Sydney Workcover Authority, New South Wales Review o
4、f Australian Standards. To keep abreast of progress in industry, Australian Standards are subject to periodic review and are kept up to date by the issue of amendments or new editions as necessary. It is important therefore that Standards users ensure that they are in possession of the latest editio
5、n, and any amendments thereto. Full details of all Australian Standards and related publications will be found in the Standards Australia Catalogue of Publications; this information is supplemented each month by the magazine The Australian Standard, which subscribing members receive, and which gives
6、 details of new publications, new editions and amendments, and of withdrawn Standards. Suggestions for improvements to Australian Standards, addressed to the head office of Standards Australia, are welcomed. Notification of any inaccuracy or ambiguity found in an Australian Standard should be made w
7、ithout delay in order that the matter may be investigated and appropriate action taken. This Standard was issued in draft form for comment as DR 88227. Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 05 Feb 2009 AS 37681990 Australian Standard Guide to the effects of temperature on electrical equipment
8、 First published as AS 37681990. Incorporating: Amdt 11995 PUBLISHED BY STANDARDS AUSTRALIA (STANDARDS ASSOCIATION OF AUSTRALIA) 1 THE CRESCENT, HOMEBUSH, NSW 2140 ISBN 0 7262 6125 4 Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 05 Feb 2009 AS 376819902 PREFACE This Standard was prepared jointly by t
9、he Standards Australia Committees on Industrial Switchgear and Controlgear and Power Switchgear, as a guide for engineers responsible for the determination of temperatures of components forming parts of electrical equipment. It is based on the Central Office draft of IEC Technical report 943 (1989)
10、Guide for the specification of permissible temperature and temperature rise for parts of electrical equipment, in particular for terminals, but is presented differently to make it easier to read and extract information relevant to particular applications. A considerable amount of explanatory materia
11、l for the development of the equations has not been included in this guide and reference should be made to IEC 943 for any further details. CopyrightSTANDARDS AUSTRALIA Users of Standards are reminded that copyright subsists in all Standards Australia publications and software. Except where the Copy
12、right Act allows and except where provided for below no publications or software produced by Standards Australia may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing from Standards Australia. Permission may be conditional on an a
13、ppropriate royalty payment. Requests for permission and information on commercial software royalties should be directed to the head office of Standards Australia. Standards Australia will permit up to 10 percent of the technical content pages of a Standard to be copied for use exclusively in-house b
14、y purchasers of the Standard without payment of a royalty or advice to Standards Australia. Standards Australia will also permit the inclusion of its copyright material in computer software programs for no royalty payment provided such programs are used exclusively in-house by the creators of the pr
15、ograms. Care should be taken to ensure that material used is from the current edition of the Standard and that it is updated whenever the Standard is amended or revised. The number and date of the Standard should therefore be clearly identified. The use of material in print form or in computer softw
16、are programs to be used commercially, with or without payment, or in commercial contracts is subject to the payment of a royalty. This policy may be varied by Standards Australia at any time. Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 05 Feb 2009 3AS 37681990 CONTENTS Page SECTION 1. SCOPE AND GEN
17、ERAL 1.1SCOPE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 1.2REFERENCED DOCUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 1.3DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18、. . . . . . . . . . . . . . .3 1.4NOTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 SECTION 2. TEMPERATURES AND TEMPERATURE-RISES OF EQUIPMENT COMPONENTS 2.0GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19、 . . . . . . . . . . . . .6 2.1TEMPERATURE AND TEMPERATURE-RISE LIMITS . . . . . . . . . . . . . . . . . . .6 2.2COMMENTS ON TABLE 2.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 2.3VARIATIONS IN THE TEMPERATURE OF THE MEDIUM (FLUID) SURROUNDING THE COMPONENT. . . . . .
20、 . . . . . . . . . . . . . . . . . . . . . . . .10 SECTION 3. EFFECT OF TEMPERATURE ON CONTACT LIFE 3.1MECHANISM OF CONTACT AGEING . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 3.2CONTACT MATERIALS, THEIR USE AND PRECAUTIONS TO BE TAKEN.12 3.3EFFECT OF THERMAL CYCLING . . . . . . . . .
21、 . . . . . . . . . . . . . . . . . . . . . . .13 SECTION 4. TEMPERATURE-RISES OF CONDUCTORS CONNECTING ELECTRICAL EQUIPMENT 4.1TEMPERATURE-RISE (Ts) OF A CONDUCTOR WITH RESPECT TO ITS FLUID ENVIRONMENT TEMPERATURE (Te) . . . . . . . . . . . . . . . . . . . . . . . .15 4.2TEMPERATURE-RISE (To) IN THE
22、 VICINITY OF CONTACTS AND CONNECTION TERMINALS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 SECTION 5. CURRENT RATINGS OF CABLES AND BUSBARS AND TEMPERA- TURE AND TEMPERATURE RISE OF TERMINALS CONNECTED THERETO 5.1CONNECTING CABLES AND BARS FOR TEMPERATURE-RISE TESTS ON E
23、QUIPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 5.2CURRENT RATINGS OF CIRCUIT CONDUCTORS FOR ELECTRICAL INSTALLATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 5.3TEMPERATURE RISE OF BUSBARS . .
24、 . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 5.4TEMPERATURE AND TEMPERATURE RISE OF EQUIPMENT TERMINALSINFLUENCE ON CONNECTED CONDUCTORS . . . . . . . . . . .23 SECTION 6. THERMAL DETERIORATION OF ELECTRICAL INSULATION MATERIALS 6.1GENERAL . . . . . . . . . . . . . . . . . . . . . . .
25、. . . . . . . . . . . . . . . . . . . . . . . . . . .30 6.2CABLE INSULATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 6.3CURRENT RATING OF INSULATED CONDUCTORS . . . . . . . . . . . . . . . . . .31 APPENDICES ARECOMMENDED CLAMPING TORQUES FOR BOLTED (SCREWED)
26、 TERMINALS AND CONNECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33 BCHARACTERISTICS OF CONDUCTOR AND CONTACT METALS . . . . . . . . . .34 CTEMPERATURERISES OF A 10 mm SQUARE COPPER BAR CARRYING 335 A .35 DDERIVATION OF THE TEMPERATURE RISE OF A CONDUCTOR IN THE VICINITY O
27、F A TERMINAL, WITH COOLING BY RADIATION AND NATURAL CONVECTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36 ECALCULATION OF TEMPERATURE-RISE AT THE JUNCTION OF TWO 1 CM SQUARE COPPER BARS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
28、. . . . . . . . . . .40 FSYMBOLS AND UNITS USED IN THIS STANDARD . . . . . . . . . . . . . . . . . . . .42 Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 05 Feb 2009 AS 376819904 STANDARDS AUSTRALIA Australian Standard Guide to the effects of temperature on electrical equipment SECTION 1. SCOPE AND GE
29、NERAL 1.1SCOPE.This guide is intended for use by engineers responsible for the determination of the effects of temperatures and temperature-rises of electrical equipment. It applies more particularly to electrical contacts, connections and terminals. It does not apply to the windings of rotating ele
30、ctrical machines or transformers. This Standard presents an overview of the following: (a)Calculations of the temperature-rises of contacts, connections and terminals. (b) Permissible temperatures and temperature-rises for various electrical components. 1.2REFERENCED DOCUMENTS.The following document
31、s are referred to in this Standard: AS 1078Guide to loading of oil-immersed transformers 1154Insulator and conductor fittings for overhead power lines 1154.1Part 1: Performance and general requirements 1852International electrotechnical vocabulary 1852(441) Switchgear, controlgear and fuses 1939Clas
32、sification of degrees of protection provided by enclosures for electrical equipment 2768Electrical insulating materialsEvaluation and classification based on thermal endurance 3000SAA Wiring Rules 3008Electrical installationsSelection of cables 3008.1Part 1: Cables for alternating voltages up to and
33、 including 0.6/1 kV 3300Approval and test specificationGeneral requirements for household and similar electrical appliances BS 4579Specification for performance of mechanical and compression joints in electrical cable and wire connectors 4579.1Part 1: Compression joints in copper conductors 4579.2Pa
34、rt 2: Compression joints in nickel, iron and plated copper conductors 4579.3Part 3: Mechanical and compression joints in aluminium conductors IEC 216Guide for the determination of thermal endurance properties of electrical insulating materials 216.1Part 1: General guidelines for ageing and evaluatio
35、n of test results 287Calculation of the continuous current rating of cables (100% load factor) 943Draft-Guide for the specification of permissible temperatures and temperature rises for parts of electrical equipment, in particular for terminals Approval testsFifty seventh chief engineers conference,
36、 April, 1972, classification C. The UK EngineeringElectricity Council. Type approval tests for connections and terminations for Recommendationaluminium conductors of insulated power cables. C79 1.3DEFINITIONS.For the purpose of this Standard the definitions given in AS 1852(441) and the following ap
37、ply: 1.3.1Ambient air temperature (Ta)temperature, determined under prescribed conditions, of the air surrounding the complete equipment. NOTES: 1. For equipment installed inside an enclosure, it is the temperature of the air outside the enclosure. 2. The value of the ambient temperature may be infl
38、uenced by the heat generated by the equipment, around which it is measured. 3. Standard values of ambient air temperature (Tan) in this guide are (a) the weighted annual mean ambient air temperature (Tan1) = 20C; and (b) the maximum ambient temperature (Tan2) = 40C. COPYRIGHT Accessed by UNIVERSITY
39、OF SOUTH AUSTRALIA on 05 Feb 2009 5AS 37681990 1.3.2Fluid environment temperature (Te)mean temperature of the air or fluid surrounding the component under consideration. 1.4NOTATION.A list of the symbols used in this Standard, with their meanings and units, is given in Appendix F. COPYRIGHT Accessed
40、 by UNIVERSITY OF SOUTH AUSTRALIA on 05 Feb 2009 AS 376819906 SECTION 2. TEMPERATURES AND TEMPERATURE- RISES OF EQUIPMENT COMPONENTS 2.0GENERAL.The reasons for concern about the temperature of electrical equipment are as follows: (a)There is a need to prevent thermal deterioration of the properties
41、of the material. (b) There is a need to ensure the thermal stability of current-carrying contacts and connections and so prevent thermal runaway. When considering thermal stability it is necessary to take cyclic thermal loading into account. 2.1TEMPERATURE AND TEMPERATURE-RISE LIMITS.Australian Stan
42、dards generally state the temperature-rise limits which must not be exceeded with a maximum ambient temperature of 40C, the mean measured value over a 24 h period not exceeding 35C. In fact, it is necessary to distinguish between two groups of values: (a)The values for components, the temperature of
43、 which should not exceed a certain value, otherwise very rapid, if not immediate destruction will occur; in this case, the ambient temperature to be taken into account is actually 40C. This applies, for example, to certain insulation, tinned contacts (creep point of tin = 105C) and certain springs.
44、NOTE: Where the maximum fluid environment temperature can exceed 40C, as frequently is the case inside enclosures, the allowable temperature-rise must be reduced so the allowable maximum temperature is not exceeded. (b) The values corresponding to components susceptible to ageing, but whose rapid de
45、struction temperature is high; e.g. the temperature-rise of spring copper contacts is limited to 35C even though they can withstand a temperature of almost 150C without immediate destruction. It is evident that, in this case, the performance is greatly affected by the mean temperature during the lif
46、e of the component, which is influenced by the weighted annual mean ambient air temperature. For the purpose of this Standard, the weighted annual mean ambient air temperature Tan1is taken as 20C. According to the location of the equipment the maximum values of temperature-rise should be determined
47、using the weighted annual mean ambient air temperatures in Figure 2.1. See AS 1078 for details concerning the determination of the weighting. Table 2.1 gives the values, shown in many switchgear Standards, which make distinction between the maximum permissible temperature-rise at the weighted mean a
48、nnual ambient air temperature (Tan1) = 20C and the maximum permissible ambient temperature (Tan2) = 40C. The values in Table 2.1 do not purport to be applicable to all types of equipment. In particular, it is considered that well designed spring contacts may suffer no disadvantage as compared to scr
49、ewed contacts, as may be inferred from the table. 2.2COMMENTS ON TABLE 2.1.The following comments are made on the values shown in Table 2.1: (a)The values indicated are applicable to equipment operating at continuous rating. (b) The permissible temperature-rises in column 2 result from (i)either long duration tests corresponding to a normal life of about 20 to 40 years, and hence from the values confirmed by experience; or (ii)short duration tests at high rating, the lifetime at normal rating having been deduced from the consideration of ageing in Clause
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