1、BRITISH STANDARD BS IEC 61865:2001 Overhead lines Calculation of the electrical component of distance between live parts and obstacles Method of calculation ICS 29.240.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBS IEC 61865:2001 This British Standard, having been prepar
2、ed under the direction of the Electrotechnical Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 29 March 2002 BSI 29 March 2002 ISBN 0 580 39248 1 National foreword This British Standard reproduces verbatim IEC 61865:2001 and i
3、mplements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee PEL/11, Overhead lines, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. From 1 January 1997, all
4、IEC publications have the number 60000 added to the old number. For instance, IEC 27 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 The British Standards
5、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 doe
6、s 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. aid enquirers to understand the text; present to the responsibl
7、e 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. Summary of pages This document comprises a front cover, an inside front cover, t
8、he IEC title page, pages 2 to 23 and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsNORME INTERNATIONALE CEI IEC INTERNATIONAL STANDARD 61865 Premire dition First edition 2001-07 L
9、ignes ariennes Calcul de la composante lectrique de la distance entre les parties sous tension et les obstacles Mthode de calcul Overhead lines Calculation of the electrical component of distance between live parts and obstacles Method of calculation Numro de rfrence Reference number CEI/IEC 61865:2
10、001 BSIEC61865:200161865 IEC:2001 3 CONTENTS FOREWORD . 3 INTRODUCTION . 5 1 Scope 6 2 Normative references. 7 3 Terms, definitions and symbols 7 3.1 Definitions 7 3.2 Symbols 9 4 Approach used to derive the electrical distance . 10 5 Overvoltages 11 5.1 Classification of overvoltages . 11 5.2 Tempo
11、rary overvoltages . 11 5.3 Slow-front overvoltages 12 5.4 Fast-front overvoltages . 12 6 Required withstand voltage of the air gap 13 6.1 General. 14 6.2 Calculation of the required withstand voltage 16 7 Calculation of the distance associated with the overvoltages . 17 Annex A (informative) Relatio
12、nship between U 50and the gap length, d . 18 Annex B (informative) Example of the calculation of the electrical component . 20 Bibliography. 23 Table 1 Slow-front waves: probability of discharge 14 Table 2 Fast-front waves: probability of discharge. 15 Table B.1 Summary of the results 22 BSIEC61865:
13、2001 BSI29March2002 261865 IEC:2001 5 INTERNATIONAL ELECTROTECHNICAL COMMISSION OVERHEAD LINES CALCULATION OF THE ELECTRICAL COMPONENT OF DISTANCE BETWEEN LIVE PARTS AND OBSTACLES METHOD OF CALCULATION FOREWORD 1) The IEC (International Electrotechnical Commission) is a worldwide organization for st
14、andardization comprising all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, the IEC pu
15、blishes International Standards. Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in
16、this preparation. The IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations. 2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an i
17、nternational consensus of opinion on the relevant subjects since each technical committee has representation from all interested National Committees. 3) The documents produced have the form of recommendations for international use and are published in the form of standards, technical specifications,
18、 technical reports or guides and they are accepted by the National Committees in that sense. 4) In order to promote international unification, IEC National Committees undertake to apply IEC International Standards transparently to the maximum extent possible in their national and regional standards.
19、 Any divergence between the IEC Standard and the corresponding national or regional standard shall be clearly indicated in the latter. 5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to be in conformity with one of its s
20、tandards. 6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 61865 has been prepared by IEC technical co
21、mmittee 11: Overhead lines. The text of this standard is based on the following documents: FDIS Report on voting 11/161/FDIS 11/162/RVD Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafte
22、d in accordance with the ISO/IEC Directives, Part 3. Annexes A and B are for information only. BSIEC61865:2001 BSI29March2002 361865 IEC:2001 7 The committee has decided that the contents of this publication will remain unchanged until 2005-11. At this date, the publication will be reconfirmed; with
23、drawn; replaced by a revised edition, or amended. BSIEC61865:2001 BSI29March2002 461865 IEC:2001 9 INTRODUCTION The minimum distances to be maintained between overhead line conductors and objects close to them are usually specified in national standards or regulations. Such minimum distances normall
24、y comprise an electrical distance, i.e. an air insulation distance which prevents an electrical discharge between the conductors and other objects, even when there are overvoltages present on the overhead line conductors; an additional distance to account for an extreme range of certain conditions (
25、such as human activities, sizes of objects that may normally come under a line, movement of conductors due to temperature, load or environmental conditions) plus a safety margin to allow for uncertainties. It is important that the two distances are specified correctly. The method presented in this I
26、nternational Standard for calculating the electrical distance is mainly for use when reviewing or revising existing electrical distances (for example, to add new voltage levels). The method uses the overvoltages which occur on the lines together with the prevailing atmospheric conditions (including
27、the effects of altitude, etc.) to derive the electrical component of the distance. The method is especially suited to the case of slow- fronted waves but is extended to cover the case of fast-front waves and temporary overvoltages. BSIEC61865:2001 BSI29March2002 561865 IEC:2001 11 OVERHEAD LINES CAL
28、CULATION OF THE ELECTRICAL COMPONENT OF DISTANCE BETWEEN LIVE PARTS AND OBSTACLES METHOD OF CALCULATION 1 Scope This International Standard provides guidance for the calculation of electrical distances between live and earthed parts required to prevent air-gap breakdown which may endanger members of
29、 the public who legitimately come close to live parts. It is applicable only to overhead lines designed to operate at more than 45 kV phase-to-phase a.c. It deals with the electrical component of distances between conductors and movable objects vehicles on the ground, vessels on water, persons on to
30、p of objects or on the ground, wildlife on the ground (but not airborne), etc. This standard does not deal with the following public and worker safety aspects: stationary objects structures beneath or next to lines, trees, ground contours, etc. These, in general, require consideration as to whether
31、the structure can be climbed on, the extent to which the tree will grow, etc; minimum approach distance for live working, which is dealt with in IEC 61472; capacitive coupling or magnetic induction by overhead lines, such as voltages induced in vehicles under a line, or in pipelines buried alongside
32、 it; currents flowing in the ground that originate from lines and result in step and touch voltages around structures during line faults or lightning strikes; flashover of line insulators or spark gaps, or a phase-to-phase discharge, resulting in audible and electrical noise and intense arcs; dielec
33、tric breakdown of the air between the conductors and the ground due to large fires beneath conductors; minimum electrical distances required to prevent discharge to adjacent overhead power or communication circuits. This standard does not give the electrical distance requirements for the design of o
34、verhead line structures. Neither does it give the distance requirements for overhead line structures which need to be accessible to workers while the line is energized (for example, distances to line workers or painters). Distances between conductors and the structure of the tower are normally chose
35、n to meet the required operating reliability of the line. It is possible that this distance may not always be adequate to allow live working or, in some cases, access for workers to parts of the structure near to live conductors. BSIEC61865:2001 BSI29March2002 661865 IEC:2001 13 2 Normative referenc
36、es The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this I
37、nternational Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of IEC and ISO maintain registers of currently valid
38、International Standards. IEC 60050(601):1985, International Electrotechnical Vocabulary (IEV) Chapter 601: Generation, transmission and distribution of electricity General IEC 60050(604):1987, International Electrotechnical Vocabulary (IEV) Chapter 604: Generation, transmission and distribution of e
39、lectricity Operation IEC 60060-1:1989, High-voltage test techniques Part 1: General definitions and test requirements lEC 60071-1:1993, Insulation co-ordination Part 1: Definitions, principles and rules lEC 60071-2:1996, Insulation co-ordination Part 2: Application guide IEC 61472:1998, Live working
40、 Minimum approach distances Method of calculation 3 Terms, definitions and symbols For the purposes of this International Standard, certain definitions from IEC 60050(601) and IEC 60050(604) as well as the following definitions apply. 3.1 Definitions 3.1.1 nominal voltage of a system suitable approx
41、imate value of voltage used to designate or identify a system IEV 601-01-21 NOTE See also IEV 601-01-29: phase-to-phase voltage. 3.1.2 highest voltage of a system U S highest value of operating voltage which occurs under normal operating conditions at any time and any point in the system IEV 601-01-
42、23 NOTE 1 See also IEV 601-01-29: phase-to-phase voltage. NOTE 2 Transient overvoltages due, for example, to switching operations and abnormal operation, as well as abnormal temporary variations of voltage, are not taken into account. BSIEC61865:2001 BSI29March2002 761865 IEC:2001 15 3.1.3 temporary
43、 overvoltage oscillatory overvoltage (at power frequency) at a given location, of relatively long duration and which is undamped or weakly damped IEV 604-03-12, modified NOTE Temporary overvoltages usually originate from switching operations or faults (for example, sudden load rejection, single phas
44、e-to-earth faults and/or from non-linearities (ferro-resonance effects, harmonics). 3.1.4 fifty per cent disruptive discharge voltage peak value of an impulse test voltage having a 50 % probability of initiating a disruptive discharge each time the dielectric testing is performed IEV 604-03-43 3.1.5
45、 power-frequency withstand voltage r.m.s. value of sinusoidal power frequency voltage that the equipment can withstand during tests made under specified conditions and for a specified time IEV 604-03-40 3.1.6 lightning overvoltage transient overvoltage, the shape of which can be regarded for insulat
46、ion coordination purposes as similar to that of the standard lightning impulse IEV 604-03-30 3.1.7 front of a voltage impulse that part of an impulse which occurs prior to the peak IEV 604-03-16 3.1.8 electrical distance D el reference distance which ensures that the electrical breakdown between any
47、 live part of the electrical installation to the body of a member of the public, or any conductive tool or object which they could reasonably be expected to be in contact with, is effectively avoided 3.1.9 occupancy at electrical distance T occ number of hours, at which the individual or any conduct
48、ive part to which he/she is in contact, is taken to be at the limit of the electrical distance NOTE As a reference, T occ is taken to be 1 h per year. 3.1.10 annual probability of breakdown of air gap R a probability of sparkover NOTE For a reference occupancy of 1 h per year at the electrical dista
49、nce, D el , the value R ais taken to be 10 7 . 3.1.11 statistical withstand voltage U 90 overvoltage, with the shape of the representative overvoltage, at which the insulation exhibits a 90 % probability of withstand BSIEC61865:2001 BSI29March2002 861865 IEC:2001 17 3.1.12 two per cent statistical overvoltage U 2 overvoltage having a 2 % probability of being exceeded, derived from
