BS-IEC-60287-1-1-2006.pdf
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1、BRITISH STANDARD BS IEC 60287-1-1:2006 Electric cables Calculation of the current rating Part 1-1: Current rating equations (100% load factor) and calculation of losses General ICS 29.060.20 ? Licensed Copy: London South Bank University, London South Bank University, Thu Mar 01 07:16:45 GMT+00:00 20
2、07, Uncontrolled Copy, (c) BSI BS IEC 60287-1-1:2006 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 January 2007 BSI 2007 ISBN 978 0 580 50127 2 National foreword This British Standard was published by BSI. It is the UK implementation of
3、IEC 60287-1-1:2006. It supersedes BS 7769-1-1:1997 which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee GEL/20, Electric cables, to Subcommittee GEL/20/16, Medium/high voltage cables. A list of organizations represented on GEL/20/16 can be obtained on requ
4、est to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. DateComment
5、s Licensed Copy: London South Bank University, London South Bank University, Thu Mar 01 07:16:45 GMT+00:00 2007, Uncontrolled Copy, (c) BSI IEC INTERNATIONAL STANDARD 60287-1-1 Second edition 2006-12 Electric cables Calculation of the current rating Part 1-1: Current rating equations (100 % load fac
6、tor) and calculation of losses General Reference number IEC 60287-1-1:2006 Licensed Copy: London South Bank University, London South Bank University, Thu Mar 01 07:16:45 GMT+00:00 2007, Uncontrolled Copy, (c) BSI CONTENTS 1 1.1 1.2 1.3 1.4 2 2.1 2.2 2.3 Loss factor for sheath and screen (applicable
7、to power frequency a.c. cables 2.4 Loss factor for armour, reinforcement and steel pipes (applicable to power Table 2 Skin and proximity effects Experimental values for the coefficients ks and kp Table 3 Values of relative permittivity and loss factors for the insulation of high- 2 BS IEC 60287-1-1:
8、2006 INTRODUCTION.3 General 4 Scope4 Normative references 4 Symbols 5 Permissible current rating of cables.8 Calculation of losses 11 AC resistance of conductor11 Dielectric losses (applicable to a.c. cables only)14 only)14 frequency a.c. cables only)23 Table 1 Electrical resistivities and temperatu
9、re coefficients of metals used.28 .29 voltage and medium-voltage cables at power frequency30 Table 4 Absorption coefficient of solar radiation for cable surfaces .31 Licensed Copy: London South Bank University, London South Bank University, Thu Mar 01 07:16:45 GMT+00:00 2007, Uncontrolled Copy, (c)
10、BSI INTRODUCTION This Part 1-1 contains formulae for the quantities R, Wd, 1 and 2. It contains methods for calculating the permissible current rating of cables from details of the permissible temperature rise, conductor resistance, losses and thermal resistivities. Formulae for the calculation of l
11、osses are also given. The formulae in this standard contain quantities which vary with cable design and materials used. The values given in the tables are either internationally agreed, for example, electrical resistivities and resistance temperature coefficients, or are those which are generally ac
12、cepted in practice, for example, thermal resistivities and permittivities of materials. In this latter category, some of the values given are not characteristic of the quality of new cables but are considered to apply to cables after a long period of use. In order that uniform and comparable results
13、 may be obtained, the current ratings should be calculated with the values given in this standard. However, where it is known with certainty that other values are more appropriate to the materials and design, then these may be used, and the corresponding current rating declared in addition, provided
14、 that the different values are quoted. Quantities related to the operating conditions of cables are liable to vary considerably from one country to another. For instance, with respect to the ambient temperature and soil thermal resistivity, the values are governed in various countries by different c
15、onsiderations. Superficial comparisons between the values used in the various countries may lead to erroneous conclusions if they are not based on common criteria: for example, there may be different expectations for the life of the cables, and in some countries design is based on maximum values of
16、soil thermal resistivity, whereas in others average values are used. Particularly, in the case of soil thermal resistivity, it is well known that this quantity is very sensitive to soil moisture content and may vary significantly with time, depending on the soil type, the topographical and meteorolo
17、gical conditions, and the cable loading. The following procedure for choosing the values for the various parameters should, therefore, be adopted. Numerical values should preferably be based on results of suitable measurements. Often such results are already included in national specifications as re
18、commended values, so that the calculation may be based on these values generally used in the country in question; a survey of such values is given in Part 3-1. A suggested list of the information required to select the appropriate type of cable is given in Part 3-1. 3 BS IEC 60287-1-1:2006 Licensed
19、Copy: London South Bank University, London South Bank University, Thu Mar 01 07:16:45 GMT+00:00 2007, Uncontrolled Copy, (c) BSI ELECTRIC CABLES CALCULATION OF THE CURRENT RATING Part 1-1: Current rating equations (100 % load factor) and calculation of losses General 1 General 1.1 Scope This part of
20、 IEC 60287 is applicable to the conditions of steady-state operation of cables at all alternating voltages, and direct voltages up to 5 kV, buried directly in the ground, in ducts, troughs or in steel pipes, both with and without partial drying-out of the soil, as well as cables in air. The term “st
21、eady state“ is intended to mean a continuous constant current (100 % load factor) just sufficient to produce asymptotically the maximum conductor temperature, the surrounding ambient conditions being assumed constant. This part provides formulae for current ratings and losses. The formulae given are
22、 essentially literal and designedly leave open the selection of certain important parameters. These may be divided into three groups: parameters related to construction of a cable (for example, thermal resistivity of insulating material) for which representative values have been selected based on pu
23、blished work; parameters related to the surrounding conditions, which may vary widely, the selection of which depends on the country in which the cables are used or are to be used; parameters which result from an agreement between manufacturer and user and which involve a margin for security of serv
24、ice (for example, maximum conductor temperature). 1.2 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 (including
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