1、BSI Standards PublicationBS EN 50541-2:2013Three phase dry-typedistribution transformers 50Hz, from 100 kVA to 3 150kVA, with highest voltage forequipment not exceeding 36kV -Part 2: Determination of loadability of atransformer loaded with non-sinusoidalcurrentBS EN 50541-2:2013 BRITISH STANDARDNati
2、onal forewordThis British Standard is the UK implementation of EN 50541-2:2013.It supersedes BS 7844-3:1998 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee PEL/14, Power transformers.A list of organizations represented on this committee can beobtained o
3、n request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2013. Published by BSI StandardsLimited 2013ISBN 978 0 580 78418 7ICS 29.180Compliance with a British
4、 Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 July 2013.Amendments issued since publicationDate Text affectedBS EN 50541-2:2013EUROPEAN STANDARD EN 50541-2 NORME EUROPENNE EUROPISCHE
5、NORM June 2013 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Brussels 2013 CENELEC - All rights of exploitation in any form and by any mean
6、s reserved worldwide for CENELEC members. Ref. No. EN 50541-2:2013 E ICS 29.180 Supersedes HD 538.3 S1:1997 English version Three phase dry-type distribution transformers 50 Hz, from 100 kVA to 3 150 kVA, with highest voltage for equipment not exceeding 36 kV - Part 2: Determination of loadability o
7、f a transformer loaded with non-sinusoidal current Transformateurs triphass de distribution de type sec 50 Hz, de 100 kVA 3 150 kVA, avec une tension la plus leve pour le matriel ne dpassant pas 36 kV - Partie 2: Dtermination de la caractristique de puissance dun transformateur avec des courants de
8、charge non-sinusodaux Drehstrom-Trocken-Verteilungstransformatoren, 50 Hz, 100 kVA bis 3 150 kVA, mit einer hchsten Spannung fr Betriebsmittel kleiner oder gleich 36 kV - Teil 2: Bestimmung der Bemessungsleistung eines Transformators bei nicht sinusfrmigen Laststrmen This European Standard was appro
9、ved by CENELEC on 2013-04-15. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such natio
10、nal standards may be obtained on application to the CEN-CENELEC Management Centre or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its ow
11、n language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia
12、, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 50541-2:2013EN 50541-2:2013 - 2 - Contents Foreword 3 1 Scope .
13、4 2 Application 4 3 Equivalent power rating . 4 4 Calculation of the factor K to obtain the equivalent power rating 4 BS EN 50541-2:2013EN 50541-2:2013 - 3 - Foreword This document (EN 50541-2:2013) has been prepared by CLC/TC 14 “Power transformers“. The following dates are fixed: latest date by wh
14、ich this document has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2014-04-15 latest date by which the national standards conflicting with this document have to be withdrawn (dow) 2016-04-15 The EN 50541 series consists of the following
15、 parts, under the general title: “Three phase dry-type distribution transformers 50 Hz, from 100 kVA to 3 150 kVA, with highest voltage for equipment not exceeding 36 kV”: Part 1: General requirements Part 2: Determination of loadability of a transformer loaded with non-sinusoidal current This docum
16、ent supersedes HD 538.3 S1:1997. BS EN 50541-2:2013EN 50541-2:2013 - 4 - 1 Scope This European Standard gives to the user guidance to determine the loadability of dry type distribution transformers, as defined in and covered by EN 50541-1, in the case of load current with harmonic factors exceeding
17、the maximum values allowed. 2 Application For normal electrical energy distribution, the allowable total harmonic factor1)and even harmonic factor due to the load current are assumed to be limited to 5 % and 1 % respectively. For electrical distribution with higher harmonic factors, it has to be tak
18、en into account that the load loss increases and, by consequence, the temperature rises in the transformer exceed those corresponding to sinusoidal currents having the same r.m.s. value. If the transformer is intended for converter operation or the harmonic factor is higher than 5 %, the matter is d
19、iscussed between purchaser and manufacturer. 3 Equivalent power rating The equivalent power rating is related to sinusoidal current which causes the same losses as those occurring with the non-sinusoidal current imposed. The equivalent power rating is equal to the power based on the r.m.s. value of
20、the non-sinusoidal current multiplied by the factor K. The rated power of the transformer to be used shall be equal to or higher than the equivalent power rating. In case a transformer in service is subsequently loaded with harmonic currents, a derating factor 1/K shall be applied to the rated power
21、. 4 Calculation of the factor K to obtain the equivalent power rating The factor K is given by the following formula2): 2122 12111+=NnnnqIInIIeeK where 1)The harmonic factor H, in percentage, is defined by: 21221100%=NnnnIIH 2)In the formula, it is assumed that both power ratings are based on the sa
22、me r.m.s. value of the load current. BS EN 50541-2:2013EN 50541-2:2013 - 5 - e = the eddy current loss due to sinusoidal current at fundamental frequency (e.g. 50 Hz), divided by the loss due to a d.c. current equal to the r.m.s. value of the sinusoidal current, both at reference temperature; n = ha
23、rmonic order; I = the r.m.s. value of the sinusoidal current and, in the other case, of non-sinusoidal current, containing all harmonics, given by 2121112112=NnnnNnnnIIIII In= the nthharmonic current (amplitude or r.m.s. value); I1= the fundamental current (amplitude or r.m.s. value); q = an exponen
24、tial constant3). 3)The exponent q is dependent on the type of windings and on the frequency. However, as an approximation and as a guidance, the following constant values may be used: 1,7 for transformers with round or rectangular wire in both the low and high voltage windings; 1,5 for transformers
25、having low voltage foil windings. Other values, based on measurements and possibly frequency dependent, may be applied by agreement between purchaser and manufacturer. This page deliberately left blankThis page deliberately left blankBSI is the national body responsible for preparing British Standar
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