21-1976 - American Standards Requirements and Test Code for Outdoor Apparatus Bushings.pdf

1、ANSI/IEEE Std 21-1976 (Supened- ANSVIEEE Std 21-1964) IEEE Standard General Requirements and Test Procedure for Outdoor Apparatus Bushings Published by The Institute of Electrical and Electronics Engineers, Inc 345 East 47th Street, New York, NY 10017, USA November 30, 1976 9806452 ANSI IEEE Std 21-

2、1976 6hpmd.r ANSI C76.1- 1976 (36.1-1964, IEEE Std 21-1964) An American National Standard IEEE General Requirements and Test Procedure for Outdoor Apparatus Bushings Approved June 3,1976 IEEE Standards Board Secretariat Institute of Electrical and Electronics Engineers, Inc Approved July 23,1976 Ame

3、rican National Standards Institute Published by The Institute of Electrical and Electronics Engineers, Inc American National Standard An American National Standard implies a consensus of those sub- stantially concerned with its scope and provisions. An American National Standard is intended as a gui

4、de to aid the manufacturer, the consumer, and the general public. The existence of an American National Standard does not in any respect preclude anyone, whether he has approved the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming

5、 to the standard. American National Standards are subject to periodic review and users are cautioned to obtain the 1atest.editions. CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action

6、 be taken to reaffirm, revise, or withdraw this standard no later than five years from the date of publication. Purchasers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute. Copyright 1976 by The Institute

7、of Electrical and Electronics Engineers, Inc. No part of this publication may be reproduced in any form, in an electronic retried system or otherwise, without the prior written permission of the publisher. Foreword This foreword is not part of IEEE Std 21-1976, IEEE General Requirements and Test Pro

8、cedure for Outdoor Ap- paratus Bushings (ANSI C76.1-1976). This document is based on the standard practices in the United States for outdoor apparatus bush- ings. It is the result of joint efforts of professional engineers, manufacturers, and users working to- gether in an American National Standard

9、s Committee C76 under the auspices of the American Na- tional Standards Institute (ANSI). The work was initially carried out under the auspices of the American Institute of Electrical Engineers (AIEE) now the Institute of Electrical and Electronics Engineers (IEEE) and the National Electrical Manufa

10、cturers Association (NEMA). The original standard, approved in 1942 as AIEE Standard 21 (which became American National Standard for Apparatus Bushings, ANSI C76.1-1943) was prepared by the Joint Committee on Bushing Stan- dardization of the Electric Machinery, Power Transmission and Distribution, a

11、nd Protection De- vices Committees of the AIEE. A supplement and partial revision, ANSI C76.la-1958, Electrical and Dimensional Characteristics of Outdoor Apparatus Bushings (used with Power Circuit Breakers and Outdoor Transformers), was prepared by the NEMA Joint Sections Committee on Outdoor Appa

12、ratus Bushings (composed of representatives of the High Voltage Insulator Section, Power Circuit Breakers Group, Switchgear Section, and the Transformers Section. It resulted from work by the regional associations of elec- trical utilities and filled the users needs for dimensional interchangeabilit

13、y. At the time of this supplement, ANSI Sectional Committee C76 foresaw the need for a general revision and updating of the standard and asked AIEE and NEMA to submit recommendations. In NEMA implementation of this request was undertaken by a Subcommittee of the Joint Sections Committee on Outdoor A

14、pparatus Bushings and resulted in a proposal which was approved in February 1960 by the Codes and Standards Committee for submission to C76 as the NEMA recom- mendation. In the AIEE a Joint Working Group consisting of members of the Transformer And Di- electric Test Committee of the Transformer Comm

15、ittee and of the Power Circuit Breaker Commit- tee was established and developed a recommendation which was submitted to ANSI Committee C76 in July 1960. The AIEE proposal was subsequently reviewed by the West Coast Subcommittee of the AIEE Transformers Committee which developed additional recommend

16、ations and submitted them to ANSI Committee C76 in November 1960. ANSI Committee C76 appointed a special Work- ing Group for Revision of ANSI C76.1-1943 to consolidate the several proposals and recommenda- tions. This became IEEE Std 21-1964 and was approved June 9, 1964, as ANSI C76.1-1964, Stan- d

17、ard Requirements and Test Code for Outdoor Apparatus Bushings; it was reaffirmed in 1970. Work on a revision was initiated in Committee C76 in August 1968. A decision was made to separate the standard into three parts: the first (C76.1) to cover the general requirements and test procedures, the seco

18、nd (C76.2) to cover explicit ratings and dimensions, and the third to be an ap- plication guide. The latter is still under consideration. Other changes in this revision included: (1) test procedure updating, (2) adding 362 through 800 kV maximum system voltage bushing elec- trical ratings with wet s

19、witching impulse test values and coordination with switching surge sparkover values of arresters, and (3) establishing dual current ratings for 115 through 196 kV insulation class bushings, since circuit breakers have a lower temperature rise, permitting a larger current rating for a given maximum a

20、mbient temperature compared to transformers. At the time it approved this standard, American National Standards Committee C76 on Apparatus Bushing Standardization had the following personnel: W. F. Giles, Chairman C. R. Muller, Secretary Organization Represented Name of Representative Electric Light

21、 and Power Group. . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . .R. L. Lindsey R. E. Minkwitz G. J. Paul K. G. Adgate (Alt) F. W. Rempe (Alt) D. 0. Craghead W. G. Patton (Alt) Organization Represented Name of Representative Institute of Electrical and Electronics Engineer

22、s . .Jakob Sabath National Electrical Manufacturers Association. . .J. K. Easley W. F. Giles, Jr E. J. Kelly D. T. Stone F. W. Benke (Alt) W. F. True (Alt) D. F. Noles T. H. Orrock L. B. Wagenaar J. P. Burkhart Tennessee Valley Authority. . .Max Fischer Bonneville Power Administration. . .W. F. Rake

23、1 Bureau of Reclamation . .G. D. Birney Ohio Brass Company . .F. R. Stockum Interpace Corporation . .G. L. Atkinson US Department of the Interior Lapp Insulator Division, When the IEEE Standards Board approved this standard on June 3, 1976, it had the following membership: William R. Kruesi, Chairma

24、n Irvin N. Howell, Jr., Vice-Chairman Ivan G. Easton, Secretary W. E. Andrus I. Kolodny J. J. Archambault B. J. Leon J. P. Markey D. R. Cochran W. H. Cook T. J. Martin Louis Costrell D. T. Michael Jay Forster V. A. Moore J. L. Koepfinger W. S. Morgan W. J. Neiswencler Gustave Shapiro R. M. Showers R

25、. A. Soderman L. W. Thomas, Sr. C. L. Wagner W. T. Wintringham Contents SECTION PAGE 1 . ScopeandPurpose . 7 1.1 Scope . 7 1.2 Purpose . 7 2 . Referenced Documents . 7 3 . Definitions . 7 4 . Serviceconditions . 8 IJsual Service Conditions . 8 4.2 Unusual Service Conditions . 9 4.1 4.3 Other Conditi

26、ons that May Affect Design and Application . 9 5 . Rating . 9 5.1 Rated Maximum Line-to-Ground Voltage . 10 5.2 RatedFrequency . 10 5.3 Rated Dielectric Strength . 10 5.4 Rated Continuous Current . 10 6.1 Electrical Requirements . 10 6.2 hlechanical Requirements . 10 6.3 Nameplate Markings . 11 7 .

27、Testprocedure . 11 7.1 Preparation of Bushings for Tests . 11 7.2 Standard Test Conditions and Equipment . 11 7.4 ProductionTests . 13 Table 1 Altitude Correction Factors . 9 . 6 . General Requirements 10 7.3 DesignTests . 12 TABLES An American National Standard IEEE General Requirements and Test Pr

28、ocedure for Outdoor Apparatus Bushings 1. Scope and Purpose 1.1 Scope. This standard applies to outdoor power class apparatus bushings which have basic impulse insulation levels of 110 kV and above for use as components of oil-filled trans- formers, oil-filled reactors, and oil circuit breakers. Thi

29、s standard does not apply to the follow- ing: ( 1) High-voltage-cable terminations (pot- heads) (2) Bushings for instrument transformers (3) Bushings for test transformers (4) Bushings in which the major insulation is provided by a gas (5) Bushings applied with gaseous insulation (other than air at

30、atmospheric pressure) ex- ternal to tile bushing (6) Bushings for distribution class circuit breakers and transformers (7) Bushings for automatic circuit reclosers and line sectionalizers (8) Bushings for oil-less and oil-poor ap- paratus 1.2 Purpose. This standard defines the special terms used, se

31、rvice conditions, rating, general requirements, and test procedure. See IEEE Std 24-1976, Electrical, Dimensional, and Re- lated Requirements for Outdoor Apparatus Bushings (ANSI C76.2-1976), for specific list- ings of values of electrical and mechanical char- acteristics, dimensions, and other rela

32、ted test and quality control requirements which are de- scribed in this standard. 2. Referenced Documents The following standards form a part of this standard to the extent specified herein. Institute of Electrical and Electronics Engi- neers (IEEE) IEEE Std 100-1972, Dictionary of Electrical and El

33、ectronics Terms (ANSI C42.100-1972) IEEE Std 4-1969, Techniques for Dielectric Tests ANSI C68.1-1968 (R1973)I IEEE SM 332-1972, Techniques for Switching Impulse Testing (ANSI C68.2-1972) IEEE Std 24-1976, Electrical, Dimensional, and Related Requirements for Outdoor Ap- paratus Bushings (ANSI C76.2-

34、1976) When the preceding standards are superseded by a revision approved by the IEEE, the revi- sion shall apply. National Electrical Manufacturers Association (NEMA) Publication 107-1964 (R1971), Methods of Measurement of Radio Influence Voltage of High Voltage Apparatus 3. Definitions For terms no

35、t specifically defined in this stan- dard see IEEE Std 100-1972, Standard Dic- tionary of Electrical and Electronics Terms ambient temperature. The temperature of the surrounding air that comes in contact with the device or equipment in which the bushing is mounted. basic impulse insulation level (B

36、IL). A reference insulation level expressed as the impulse crest voltage of the 1.2 X 50 ps wave which the bushing will withstand when tested in accord- ance with specified conditions. bushing. An insulating structure, including a through conductor or providing a central pass- age for such a conduct

37、or, with provision for (ANSI C42.100-1972). 7 ANSI C76.1-1976 IEEE GENERAL REQUIREMENTS AND TEST mounting on a barrier, conducting or other- wise, for the purpose of insulating the conduc- tor from the barrier and conducting current from one side of the barrier to the other. bushing potential tap. A

38、n insulated connection to one of the conducting layers of a bushing providing a capacitance voltage divider to indi- cate the voltage applied to the bushing. bushing test tap. An insulated connection to one of the conducting layers of a bushing for the purpose of making insulation power factor tests

39、. capacitance (of bushing). (1) The main capaci- tance, C1, of a condenser bushing is the value in picofarads between the high-voltage conduc- tor and the potential tap or the test tap. (2) The tap capacitance, C2 , of a condenser bush- ing is the value in picrofarads between the po- tential tap and

40、 mounting flange (ground). (3) The capacitance, C, of a bushing without a potential or test tap is the value in picofarads between the high-voltage conductor and the mounting flange (ground). composite bushing. A bushing in which the major insulation consists of several coaxial layers of different i

41、nsulation materials. compound-filled bushing. A bushing in which the space between the inside surface of the weather casing and the major insulation (or conductor where no major insulation is used) is filled with insulating compound. condenser bushing. A bushing in which cy- lindrical conducting lay

42、ers are arranged co- axially with the conductor within the insulat- ing material for the purpose of controlling the electric field of the bushing. creep distance. The distance measured along the external contour of the weather casing separating the metal parts which have the op- erating line-to-grou

43、nd voltage between them. insulation class (bushing). The voltage by which the bushing is identified and which designates the level on which the electrical per- formance requirements are based. interchangeable bushing. A bushing designed for use in both power transformers and circuit breakers. ioniza

44、tion. The formation of limited avalanches of electrons developed in insulation due to an electric field. Ionization current is the result of capacitive discharges in an insulating medi- um due to electron avalanches under the in- fluence of an electric field. NOTE: The occurrence of such currents may cause (1) radio noise; (2) damage to insulation. major insulation. Insulating material internal to the bushing between the line potential conduc- tor and ground. oil. As used in this standard, oil refers to min- eral transformer oil. oil-filled bushi