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1、BRITISH STANDARD BS 7821-3: 1995 Three phase oil-immersed distribution transformers, 50 Hz, from 50 to 2500 kVA with highest voltage for equipment not exceeding 36 kV Part 3: Supplementary requirements for transformers with highest voltage for equipment equal to 36 kV (Implementation of CENELEC HD 4
2、28.3 S1:1994) UDC 621.314.212:621.3.025.3 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:29:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7821-3:1995 This British Standard, having been prepared under the direction of the Electrotechnical Sector Board, was
3、 published under the authority of the Standards Board and comes into effect on 15 September 1995 BSI 08-1999 The following BSI references relate to the work on this standard: Committee reference PEL/14 Draft for comment 92/29057 DC ISBN 0 580 24720 1 Committees responsible for this British Standard
4、The preparation of this British Standard was entrusted to Technical Committee PEL/14, Power transformers, upon which the following bodies were represented: Association of Consulting Engineers BEAMA Ltd. (Transmission and Distribution Association) British Cable Makers Confederation British Pump Manuf
5、acturers Association British Railways Board Electricity Association Institution of Plant Engineers Transmission and Distribution Association (BEAMA Ltd.) Amendments issued since publication Amd. No.DateComments Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:
6、29:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7821-3:1995 BSI 08-1999i Contents Page Committees responsibleInside front cover National forewordii Foreword2 1General3 2Electrical characteristics3 3Design requirements4 4Dimensional characteristics4 5Accessories5 Table I3 Table II4 Table III4 Lis
7、t of referencesInside back cover Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:29:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7821-3:1995 ii BSI 08-1999 National foreword This British Standard has been prepared by Technical Committee PEL/14 and impleme
8、nts HD 428.3 S1:1994, published by the European Committee for Electrotechnical Standardization (CENELEC). A British Standard does 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 Sta
9、ndard does not of itself confer immunity from legal obligations. Cross-references Publication referred toCorresponding British Standard BS 171 Power transformers HD 398.1:1980Part 1:1978 General HD 398.3:1986Part 3:1987 Specification for insulation levels and dielectric HD 428.1 S1:1992BS 7821 Three
10、 phase oil-immersed distribution transformers, 50 Hz, from 50 to 2 500 kVA with highest voltage for equipment not exceeding 36 kV Part 1:1995 General requirements and requirements for transformers with highest voltage for equipment not exceeding 24 kV Summary of pages This document comprises a front
11、 cover, an inside front cover, pages i and ii, the HD title page, pages 2 to 6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy:
12、 London South Bank University, London South Bank University, Fri Dec 08 12:29:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI HARMONIZATION DOCUMENT DOCUMENT DHARMONISATION HARMONISIERUNGSDOCUMENT HD 428.3 S1 March 1994 UDC 621.314.212:621.3.025.3 Descriptors: Electrical transformer, power transformer
13、, three phase transformer, immersed transformer, electrical rating, dimension, design English version Three phase oil-immersed distribution transformers 50 Hz, from 50 to 2 500 kVA with highest voltage for equipment not exceeding 36 kV Part 3: Supplementary requirements for transformers with highest
14、 voltage for equipment equal to 36 kV Transformateurs triphass de distribution immergs dans lhuile, 50 Hz, de 50 2 500 kVA, avec une tension la plus leve pour le matriel ne dpassant pas 36 kV Partie 3: Prescriptions complmentaires pour les transformateurs avec une tension la plus leve pour le matrie
15、l gale 36 kV Drehstrom-l-Verteilungs transformatoren 50 Hz von 50 bis 2 500 kVA, mit einer hchsten Spannung fr Betriebsmittel von 36 kV Teil 3: Ergnzend Festlegungen fr Transformatoren mit einer hchsten Spannung fr Betriebsmittel von 36 kV This Harmonization Document was approved by CENELEC on 1993-
16、09-22. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for implementation of this Harmonization Document on a national level. Up-to-date lists and bibliographical references concerning national implementation may be obtained on application
17、 to the Central Secretariat or to any CENELEC member. This Harmonization Document exists in three official versions (English, French, German). CENELEC members are the national electrotechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembo
18、urg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels
19、 1994 Copyright reserved to CENELEC members Ref. No. HD 428.3 S1:1994 E Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:29:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7821-3:1995 BSI 08-1999 2 Foreword This Part 3 of HD 428 was prepared by WG 3 of Techni
20、cal Committee CENELEC TC 14, Power transformers. The document was submitted to the Unique Acceptance Procedure (UAP) and was approved by CENELEC as HD 428.3 S1 on 1993-09-22. The following dates were fixed: latest date of announcement of the HD at national level(doa) 1994-03-01 latest date of public
21、ation of a harmonized national standard(dop) 1994-09-01 latest date of withdrawal of conflicting national standards(dow) 1994-09-01 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:29:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7821-3:1995 BSI 08-19993 1
22、General 1.1 Scope This Harmonization Document covers transformers from 50 to 2 500 kVA intended for operation in three-phase distribution networks, for indoor or outdoor continuous service, 50 Hz, immersed in mineral-oil, natural cooling, with two windings: a primary (high-voltage) winding with a hi
23、ghest voltage for equipment equal to 36 kV; a secondary (low-voltage) winding with a highest voltage for equipment not exceeding 1,1 kV. NOTE 1This document may be applied, either as a whole or in part, to transformers immersed in a synthetic insulating liquid. NOTE 2This document may be applied, ei
24、ther as a whole or in part, to transformers having windings with more than one rated voltage. In this case the rated power for each rated voltage shall be specified by the purchaser. 1.2 Object The object of this document is to lay down requirements related to electrical characteristics, dimensions
25、and design. Other requirements may be specified in a national standard. 1.3 Compliance with current Harmonization Documents Transformers shall be in accordance with Harmonization Documents of the HD 398 series. Unless herein otherwise indicated the requirements specified in HD 428.1 S1 apply also to
26、 this document. 2 Electrical characteristics 2.1 Rated power See HD 428.1 S1. 2.2 Highest voltages for equipment of windings The values of the highest voltage for equipment are: 2.3 Rated voltages of windings a) For the high-voltage winding: The preferred range of values of the rated voltage Ur is r
27、elated to the value of the highest voltage for equipment Um as stated in Table I. Table I b) For the low-voltage winding: See HD 428.1 S1. 2.4 Tappings The high-voltage winding is normally provided with tappings corresponding to a tapping range of 2,5 % or 2 2,5 %, or + 2 2,5 % 3 2,5 % to be specifi
28、ed by the purchaser. These tappings shall be connected to an off-circuit tap-changing device. Upon special agreement between purchaser and manufacturer, internal reconnecting links can be used as an alternative. 2.5 Connections See HD 428.1 S1. 2.6 Dimensioning of neutral connection of the low-volta
29、ge winding See HD 428.1 S1. 2.7 Short-circuit impedance The preferred values of the short-circuit impedance at a reference temperature of 75 C are: NOTEOther values of short-circuit impedance may be specified by the purchaser for particular system service conditions, e.g. in the case of parallel ope
30、ration. 2.8 Losses and sound power level For transformers having preferred values of rated power and short-circuit impedance in accordance with subclauses 2.1 and 2.7, the values of losses and sound power levels are stated in Table II (load losses) and Table III (no-load losses and sound power level
31、s). a) For the high-voltage winding:36 kV b) For the low-voltage winding:1,1 kV Um (kV)36 Ur (kV)25 to 34,5 Up to 630 kVA:4,5 % or 6 % Above 630 kVA:6 % or 7 % Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:29:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS
32、 7821-3:1995 4 BSI 08-1999 Table II Table III Any combination of Po and Pk lists is allowed. With respect to the listed loss values, deviations in the range of 5 % are admitted in national standards. The losses for transformers having rated power included among the non-preferred values (subclause 2.
33、1) should be obtained by interpolation. The sound levels given in Table III are the maximum admitted (no tolerance). Lower sound levels can be specified by the purchaser. When the loss values stated in the above Table II and Table III do not correspond to the actual evaluation of the energy cost, or
34、 in case of established practice in the market, or in case of special feature, the transformers can be requested and, by consequence, offered, with losses differing from the tabled losses. In such a case, a formula for capitalization of losses shall be stated in the request. The formula should be of
35、 the following type: CC = CT + APo + BPk where: Other terms may be introduced in the formula by a national committee or by a purchaser, to take into account other technical and financial aspects. Within the limits of tolerances (HD 398.1), the application of penalties/bonus with regard to losses is
36、left to the agreement between manufacturer and purchaser at the time of enquiry and order. 2.9 Insulation levels and dielectric tests See HD 428.1 S1. 3 Design requirements See HD 428.1 S1. 4 Dimensional characteristics 4.1 Rollers See HD 428.1 S1. 4.2 Distance between bushings 4.2.1 Distances betwe
37、en high-voltage oil-air bushings The preferred value of the distance between centres is 365 mm. For transformers with a highest voltage for equipment equal to 36 kV, the minimum distance between metallic parts of the heads shall be 315 mm and between the highest sheds 180 mm. However, shorter distan
38、ces may be agreed, subject to confirmation by test or by service experience. NOTE 1If the user intends to make the connections to the transformer in a way which may reduce the clearances provided by the transformer itself, then this should be brought to attention in the enquiry (See HD 398.3, clause
39、 2). NOTE 2When an oil-immersed transformer is specified for operation at an altitude higher than 1 000 m, clearances should be designed accordingly. It may then be necessary to select bushings designed for higher insulation levels than those specified for the internal insulation of the transformer
40、windings (See HD 398.3, clause 2). Rated power kVA List D Pk W List E Pk W Short-circuit impedance 50 100 160 250 400 630 1 250 1 950 2 550 3 500 4 900 6 650 1 450 2 350 3 350 4 250 6 200 8 800 4,5 % or 6 % 1 000 1 600 2 500 10 500 17 000 26 500 13 000 19 200 29 400 6 % or 7 % Pk = Load loss Rated p
41、ower List DList EShort-circuit impedance kVAPo W LWA dB Po W LWA dB % 50 100 160 250 400 630 230 380 520 780 1 120 1 450 52 56 59 62 65 67 190 320 460 650 930 1 300 52 56 59 62 65 67 4,5 % or 6 % 1 000 1 600 2 500 2 000 2 800 4 100 68 71 76 1 700 2 600 3 800 68 71 76 6 % or 7 % Po = No-load Loss LWA
42、 = Sound power level CC=capitalized cost CT=tendered price A=value indicated by the purchaser in tender invitation expressed in monetary value per watt corresponding to no-load loss Po=guaranteed no-load loss in watts B=value indicated by the purchaser in tender invitation expressed in monetary valu
43、e per watt corresponding to load loss Pk=guaranteed load loss in watts Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:29:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7821-3:1995 BSI 08-19995 4.2.2 Preferred distance between centres of low-voltage bushing
44、s See HD 428.1 S1. 4.2.3 Cable boxes For transformers in which the terminations are made in cable boxes, HD 428.2.1 applies. 5 Accessories See HD 428.1 S1. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:29:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 6 blan
45、k Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:29:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7821-3:1995 BSI 08-1999 List of references See national foreword. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:29
46、:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7821-3: 1995 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. I
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