1、CENELEC ENub0383-2 i5 3404583 OLb204b 912 = BRITISH STANDARD Insulators for overhead lines with a nominal voltage above Part 2. Insulator strings and insulator sets for a.c. systems - Definitions, test methods and acceptance criteria The European Standard EN 60383-2 : 1995 has the status of a Britis
2、h Standard ICs 29.080.10 BS EN 60383-2 : 1995 CENELEC ENab0383-2 95 3404583 Olb20Y7 859 Amd. No. BS EN 60383-2 1996; Date Text affected This British Standard, having been prepared under the direction of the Electrotechnicai Sector Board, was published under the authority of the Standards Board and c
3、omes into effect on 15 November 1995 Committees responsible for this British Standard The preparation of this British standard was entrusted to Technical Committee PEy36, Insulators for power systems, upon which the foilowing bodies were represented Association of Consdtjng Engineers Association of
4、Manufacturers Allied to the Electrical and Electronic British Industrial Ceramic Manufacturers Association British Railways Board Electrid and Electronic insulation Association (BEAMA Ltd.) Electricity Association Overhead ilansmission Line Contractors (BEAMA Ltd.) ?i.ansmission and Distribution Ass
5、ociation (BEAMA La.) Industry (BEAMA Ltd.) The foilowing body was also represented in the drafhg of the standard, through subcommitkes and paneis BEAMA Electrid Cable and Conductor Accessory Manufacturers Association Amendments issued since publication O BSI 1995 The following BSI references relate
6、to the work on this standard: Committee reference PEU36 DraR for comment 92/21397 DC ISBN O 680 24680 9 CENELEC ENab0383-2 95 3404583 0362048 795 H BS EN 60383-2 : 1995 Contents Committees responsible Nationai foreword page Inside hnt cover ii Foreword Text of EN 6032332 2 3 i BS EN 60383-2 1996 Nat
7、ional foreword This British Standard has been prepared by Technid Committee PELL36 and is the English language version of EN 603832 : 1995 Insulators for ovwizmd lines with a nominal voltage above 1 O00 V Purt 2: Insulator strings and insulator sets for a.c. sgsterns -Definitions, test methods and a
8、cqtance critema, published by the European Committee for Electsotechnid Standaukation (CENELEC). It is identical with IEC 383-2 : 1993, published by the International Electrotechnid Commission (IEC). This British Standard supersedes Bs 137 : Part 1 : 1982 which is withdrawn. That document was based
9、in part on IEC 383 : Part 1, which is envisaged to be adopted by CENELEC as EN 603831. Cross-references Publications referred to IEC 50(471) : 1984 HD 588.1 s1: 1991 (IEC 60-1 : 1989) IEC 71-1 : 1976 HD 540.2 SI : 1991 (IEC 71-2 : 1976) Corresponding British Standard BS 4727 Glossaqy of ekctmteehnid
10、, poww, telecommunication, electronics, lighling und colOur terms Part 1 Tm mnwn to poww, telecommunicat and electmnics Group 12 : 1991 Insulators BS 923 : Guide on high-voltage testing techniques Partl: 199GeneraL BS 5622 : Guide for insulation co-ordination Part 1 : 1979 Terms, b) the specified we
11、t switching impulse withstand voltage; c) the specified wet power-frequency withstand voltage. 1 The applicability of these characteristics as a function of the highest voltage for equipment shall be determined by reference to IEC 71 -1, 2 and 3 - Insulation coordination. Operating voltage is not to
12、 be considered as a characteristic of an insulator string or an insulator set. CENELEC EN*b0383-2 75 31401-1583 OLb205b 8bL Page 7 EN 60383-2 : 1996 The flash-over and withstand voltages of insulators under service conditions may differ from the flash-over and withstand voltages under standard condi
13、tions. This effect has been recognized with lightning impulse testing, especially for very high voltages of equip- ment, but the effect of ambient conditions and the arrangement of insulators and associ- ated metalwork is much greater with switching impulses due to the differences in electric field
14、distribution between the standard test arrangement and the mounting arrangement in service. The switching impulse withstand voltage of an insulator string or an insulator set is not necessarily a definite characteristic because it is determined to a large extent by the tower structure and the field
15、configuration which depends on the shape and relative positions of all the metal paris. Therefore, the verification of the specified switching impulse withstand voltage is generally required with a mounting arrangement which closely represents service conditions. The details of the mounting arrangem
16、ent shall then be agreed between the manufacturer and the purchaser at the time of ordering. Section 2: Test procedures for electrical tests 5 General requirements for high voltage tests a) The lightning and switching impulse voltage and power-frequency voltage test methods shall be in accordance wi
17、th IEC 60-1. b) Lightning and switching impulse voltages shall be expressed by their prospective peak values and power-frequency voltages shall be expressed as peak values divided by 6 c) When the natural atmospheric conditions at the time of the test differ from the standard values (see 6.1), it is
18、 necessary to apply correction factors in accordance with 6.2. d) The insulators shall be clean and dry before starting high-voltage tests. e) Special precautions shall be taken to avoid condensation on the surface of the test object especially when the relative humidity is high. For example. the te
19、st object shall be maintained at the ambient temperature of the test location for sufficient time for thermal equilibrium to be reached before the test starts. Except by agreement between the manufacturer and the purchaser, tests shall not be made if the relative humidity exceeds 85 %. f) The time i
20、ntervals between consecutive applications of the voltage shall be sufficient to minimize effects from the previous application of voltage in flash-over or withstand tests. CENELEC EN+b0383-2 95 3404583 03bi5057 7T8 Page 8 EN 60383-2 : 1995 6 Standard atmospheric conditions and correction factors for
21、 electrical tests . 6.1 Standard reference atmosphere The standard reference atmospheric conditions shall be in accordance with IEC 60-1. 6.2 The correction factors shall be determined in accordance with IEC 60-1. If the atmospheric conditions at the time of test differ from the standard reference a
22、tmosphere, then the correction factors for air density (k,) and humidity (k2) shall be calculated and the product K= k, x k2 determined. The test voltages shall then be corrected as follows: Correction factors for atmospheric conditions Withstand voltages (impulse and power frequency) Applied test v
23、oltage = Kx specified withstand voltage Flash-over voltages (impulse and power frequency) Measured f las h-over voltage K Recorded flash-over voltage = NOTE - For wet tests no correction for humidity is applied .e. 5 = 1 et K= k,. 7 Artificial tain parameters for wet tests The standard wet test proc
24、edure described in IEC 60-1 shall be used. The characteristics of the artificial rain shall be in accordance with the requirements of IEC 60-1. When tests are made on insulators in the horizontal or inclined positions, an agreement shall be reached between the manufacturer and the purchaser regardin
25、g the direction of the rainfall. 8 Mounting arrangements for electrical tests The particular mounting arrangements are specified in clause 12. 9 Lightning Impulse voltage tests One insulator string or one insulator set shall be tested using a procedure laid down in IEC 60-1. The standard 1,2/50 ligh
26、tning impulse shall be used (see IEC 60-1). The insulator shall be tested under the conditions prescribed in clauses 5 and 6. Impulses of both positive and negative polarity shall be used. However, when it is evident which polarity will give the lower withstand voltage, it shall suffice to test with
27、 that polarity. CENELEC EN*b0383-2 95 3404583 0162058 b34 E Page 9 EN 60383-2 : 1995 The normal procedure for determining the dry lightning withstand voltage on insulator strings and insulator sets shall be by calculation from the 50 % flash-over level determined by the up and down method described
28、in IEC 60-1. In the case of very long insulator strings and insulator sets, where the length is deter- mined by pollution performance rather than impulse voltage performance, it is necessary to use the withstand procedure with 15 impulses. The insulators shall not be damaged by these tests; but slig
29、ht marks on the surface of the insulating parts or chipping of the cement or other material used for assembly shall be permitted. 10 Wet power-frequency voltage tests One insulator string or one insulator set shall be tested using a procedure laid down in IEC 60-1. The test circuit shall be in accor
30、dance with IEC 60-1. The insulator shall be tested under the conditions prescribed in clauses 5, 6 and 7. The characteristics of the artificial rain shall be in accordance with the requirements of IEC 60-1. The test voltage to be applied to the test object shall be the specified wet power-frequency
31、withstand voltage adjusted for atmospheric conditions at the time of the test (refer to 6.2). The test voltage shall be maintained at this value for 1 min. NOTE - When this test is carried out on insulators for overhead traction lines, the frequency of the test voltage is considered applicable for i
32、nsulators intended for use at other frequencies from O Hz to 100 Hz. No flashover or puncture shall occur during the test. To provide information, and when specially requested at the time of ordering, the wet flashover voltage of the insulator may be determined by increasing the voltage gradually fr
33、om about 75 % of the wet power-frequency withstand voltage with a rate of rise of about 2 % of this,voltage per second. The flash-over voltage shall be the arithmetic mean of five consecutive readings and the value after correction to standard atmospheric conditions (see 6.2) shall be recorded. 11 W
34、et swltchlng impulse voltage tests One insulator string or one insulator set shall be tested using a procedure laid down in IEC 60-1. The standard 250/2 500 switching impulse shall be used (see IEC 60-1). The insulator shall be tested under the conditions prescribed in clauses 5, 6 and 7. CENELEC EN
35、ab0383-2 75 3404583 03b2057 570 Page 10 EN 60383-2 1995 The characteristics of the artificial rain shall be in accordance with the requirements of IEC 60-1. Impulses of both positive and negative polarity shall be used. The normal procedure for determining the wet switching impulse withstand voltage
36、 on insulator strings and insulator sets shall be by calculation from the 50 % flash-over level determined by the up and down method described in IEC 60-1. Difficulties may sometimes occur in applying the 50 Yo flash-over procedure because, for example, many flash-overs appear elsewhere than on the
37、insulator string or because of the need for an excessively high test voltage due to over-dimensioning of the insulator string. If such difficulties occur, by agreement the withstand procedure with 15 impulses may be used. The insulators shall not be damaged by these tests; but slight marks on the su
38、rface of the insulating parts or chipping of the cement or other material used for assembly shall be permitted. 12 Methods of mountlng The mounting arrangements for electrical tests on insulator strings and sets depend on whether switching impulse tests are required (see clause 4) and on whether ser
39、vice conditions are to be reproduced. 12.1 Standard mounting arrangement of an insulator string or insulator set when switching impulse tests are not required The insulator string or set shall be suspended vertically by means of an earthed wire rope or other suitable conductor from a supporting stru
40、cture. The distance between the uppermost point of the insulator metalwork and the supporting structure shall be not less than 1 m. No other object shall be nearer to the insulator than 1 m or 1.5 times the length of the insulator string, whichever be the greater. A length of conductor in the form o
41、f a straight, smooth metal rod or tube shall be attached to the lower integral fitting of the insulator string so that it lies in a horizontal plane and the distance from the lowest shed of the porcelain or glass part to the upper surface of the conductor shall be as short as possible but greater th
42、an 03 times the diameter of the lowest insulator. The diameter of the conductor shall be about 1.5 Yo of the length of the insulator string with a minimum of 25 mm. The length of the conductor shall be at least 1,5 times that of the insulator string, and it shall extend at least 1 m on each side of
43、the vertical axis. Precautions shall betaken to avoid flash-over from the ends of the conductor. The test voltage shall be applied between the conductor and earth. CENELEC EN*b0383-2 95 3404583 0162060 292 I Page 11 EN 60383-2 : 1995 12.2 Standard mounting arrangement of an insulator string or insul
44、ator set when switching impulse tests are required The- insulator string or set shall be suspended vertically in an arrangement simulating the tower body and cross-arm. The cross-arm is simulated by a horizontal member, the insulator string being at one end and the vertical member simulating the tow
45、er body at the other. Both members and the link supporting the insulator string shall be earthed. The width of each member facing the insulator string shall be from 400 mm minimum to at least 20 % of the length of the insulator string. The distance between the axis of the insulator string and the ve
46、rtical member simulating the tower body shall be between 1,2 and 1.5 times the length of the insulator string. The distance between the uppermost point of the insulator string and the lower part of the horizontal member simulating the cross- arm shall be equal to about 300 mm. The member simulating
47、the tower body shall extend to at least twice the length of the insulator string below the member simulating the tower cross-arm. A bundle consisting of two subconductors in the form of straight smooth metal rods or tubes shall be attached to the lower integral fittings of the insulator string at ri
48、ght angles to the cross-arm. The two subconductors of the bundle shall be maintained parallel by means of horizontal spacers; the subcanductor spacing shall be about equal to one-tenth of the length of the insulator string; the bundle shall extend approximately the length of the insulator string on
49、each side of the axis of the insulator string and the diameter of each subconductor shall be between 0,75 % and 1.25 % of the length of the insulator string. To avoid spark-over from the two ends of the bundle, each end shall be protected by means of a suitable device (for instance by means of a metal ring). The height of the conductor above ground shall be equal to about 1,5 times the length of the insulator string, but not less than 6 m. The test voltage shall be applied between the conductor bundle and earth, the high voltage connection being made at one end of the conductor
