1、BRITISH STANDARD Power transformers - Part 10: Determination of sound levels The European Standard EN 60076-10:2001 has the status of a British Standard ICs 29.180 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMiTTED BY COPYRIGHT LAW BS EN IEC 60 O 76-1 0:200 1 60076-10:ZOOl BS EN 60076-10:2001 Amd
2、. No. National foreword Date Comments This British Standard, having been prepared under the direction of the Electrotechnical Sector Policy and Strategy Committee title, was published under the authority of the Standards Policy and Strategy Committee on 5 September 2001 0 ES1 5 September 2001 This B
3、ritish Standard is the official English language version of EN 60076-10:2001. It is identical with IEC 60076-10:2001. It supersedes BS EN 60551:1993 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee PELI14, Power transformers, which has the responsibili
4、ty to: - - aid enquirers to understand the text; present to the responsible 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. - A li
5、st of organizations represented on this committee can be obtained on request to its secretary. From 1 January 1997, all IEC publications have the number 60000 added to the old number. For instance, IEC 27-1 has been renumbered as IEC 60027-1. For a period of time during the change over from one numb
6、ering system to the other, publications may contain identifiers from both systems. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standard
7、s Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include ail the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard
8、does not of itselfconfer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 35 and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. 2 ISBN O 580 3828
9、4 2 EUROPEAN STANDARD EN 60076-10 NORME EUROPENNE EUROPISCHE NORM July 2001 ICs 29.180 Supersedes EN 60551:1992 +A1:1997 English version Power transformers Part IO: Determination of sound levels (IEC 60076-1 0:ZOOI) Transformateurs de puissance Partie 1 O: Dtermination des niveaux de bruit (CE1 6007
10、6-10:2001) Leistungstransformatoren Teil IO: Bestimmung der Geruschpegel (IEC 60076-10:2001) This European Standard was approved by CENELEC on 2001-06-01. CENELEC members are bound to comply with the CENKENELEC Internal Regulations which stipulate the conditions for giving this European Standard the
11、 status of a national standard without any alteration. Up-to-date lists and bibliographiml references concerning such national standards may be obtained on application to the Central secretariat or to any CENELEC member. This European Standard exists in three offiaal versions (English, French, Germa
12、n). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Rep
13、ublic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr
14、Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 0 2001 CENELEC - All rights of exploitation in any form and by any means reserved worldwide far CENELEC members. Ref. No. EN 60076-10:2001 E EN 60076-1O:ZOOl Foreword The text of document 14/390/FDIS, future edition
15、 1 of IEC 60076-10, prepared by IEC TC 14, Power transformers, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60076-10 on 2001-06-01. This European Standard supersedes EN 60551 :I992 + A1:1997. The following dates were fixed: 2 - latest date by which the EN has to b
16、e implemented at national level by publication of an identical national standard or by endorsement - latest date by which the national standards conflicting with the EN have to be withdrawn Annexes designated “normative“ are pari of the body of the standard. Annexes designated “informative” are give
17、n for information only. in this standard, annex ZA is normative and annexes A and B are informative. Annex ZA has been added by CENELEC. (dop) 2002-03-01 (dOW) 2004-06-01 Endorsement notice The text of the International Standard IEC 60076-10:2001 was approved by CENELEC as a European Standard withou
18、t any modification. EN 60076-10:2001 CONTENTS INTRODUCTION 4 Scope 6 Normative references . 6 Definitions . 7 instrumentation and calibration 8 Choice of test method 8 Load conditions . 8 6.1 General 8 6.2 6.3 6.4 Reduced-load current 10 Principal radiating surface 10 7.1 General . 10 7.2 Transforme
19、rs with or without cooling auxiliaries, dry-type transformers in enclosures and dry-type transformers with cooling auxiliaries inside the enclosure 10 7.3 Cooling auxiliaries mounted on a separate structure spaced 23 m away from the principal radiating surface of the transformer . 10 7.4 Prescribed
20、contour 11 Microphone positions 11 No-load current and rated voltage . 9 Rated current and short-circuit voltage . 9 Dry-type transformers without enclosures 1 0 10 Calculation of the area of the measurement surface 11 10.1 Measurements made at O, 3 m from the principal radiating surface . 11 10.2 M
21、easurements made at 2 m from the principal radiating surface 12 10.3 Measurements made at 1 m from the principal radiating surface 12 10.4 Measurements on test objects where safety clearance considerations require a measurement distance which for all or part of the prescribed contour(s) exceeds the
22、provisions of 10.1 to 10.3 . 12 11 Sound pressure method 12 1 I .I Test environment . 12 11.2 Sound pressure level measurements . 15 11.3 Calculation of average sound pressure level 15 12 Sound intensity method 17 12.1 Test environment . 17 12.2 Sound intensity level measurements 17 12.3 Calculation
23、 of average sound intensity level 17 13 Calculation of sound power level . 18 14 Addition of no-load and load current sound power levels . 19 15 Far-field calculations . 19 16 Presentation of results 19 Annex A (informative) Narrow-band and time-synchronous measurements . 28 Annex 6 (informative) Ty
24、pical report of sound level determination 30 Annex ZA (normative) Normative references to international publications with their corresponding European publications . 35 0 BSI 5 September 2001 EN 60076-10:2001 I NTROD U CT I ON One of the many parameters to be considered when designing and siting tra
25、nsformers, reactors and their associated cooling equipment is the amount of sound that the equipment is likely to emit under normal operating conditions on site. Sources of sound The audible sound radiated by transformers is generated by a combination of magnetostrictive deformation of the core and
26、electromagnetic forces in the windings, tank walls and magnetic shields. Historically, the sound generated by the magnetic field inducing longitudinal vibrations in the core laminations has been dominant. The amplitude of these vibrations depends on the flux density in the laminations and the magnet
27、ic properties of the core steel, and is therefore independent of the load current. Recent advances in core design, combined with the use of low induction levels, have reduced the amount of sound generated in the core such that the sound caused by the electromagnetic forces may become significant. Cu
28、rrent flowing in the winding conductors produces electromagnetic forces in the windings. In addition, stray magnetic fields may induce vibrations in structural components. The force (and therefore the amplitude of the vibrations) is proportional to the square of the current, and the radiated sound p
29、ower is proportional to the square of the vibrational amplitude. Consequently, the radiated sound power is strongly dependent on the load current. Vibrations in core and winding assemblies can then induce sympathetic vibrations in tank walls, magnetic shields and air ducts (if present). In the case
30、of dry-type, air-cored shunt or series reactors, sound is generated by electromagnetic forces acting on the windings in a similar manner to that described above. These oscillatory forces cause the reactor to vibrate both axially and radially, and the axial and radial supports and manufacturing toler
31、ances may result in the excitation of modes in addition to those of rotational symmetry. In the case of iron-cored reactors, further vibrations are induced by forces acting in the magnetic circuit. For all electrical plants, the consequence of the presence of higher harmonics on the power supply sho
32、uld be understood. Normally, vibrations occur at even harmonics of the power frequency, with the first harmonic being dominant. If other frequencies are present in the power supply, other forces may be induced. For certain applications, this may be significant, particularly because the human ear is
33、more sensitive to these higher frequencies. Any associated cooling equipment will also generate noise when operating. Fans and pumps both tend to generate broad-band noise due to the forced flow of air or oil. Measurement of sou nd Sound level measurements have been developed to quantify pressure va
34、riations in air that a human ear can detect. The smallest pressure variation that a healthy human ear can detect is 20 pPa. This is the reference level (O dB) to which all the other levels are compared. The perceived loudness of a signal is dependent upon the sensitivity of the human ear to its freq
35、uency spectrum. Modern measuring instruments process sound signals through electronic networks, the sensitivity of which varies with frequency in a manner similar to the human ear. This has resulted in a number of internationally standardized weightings of which the A- weighting network is the most
36、common. Sound intensity is defined as the rate of energy flow per unit area and is measured in watts per square metre. It is a vector quantity whereas, sound pressure is a scalar quantity and is defined only by its magnitude. 4 BSI 5 September 2001 EN 60076-10:ZOOl Sound power is the parameter which
37、 is used for rating and comparing sound sources. It is a basic descriptor of a sources acoustic output, and therefore an absolute physical property of the source alone which is independent of any external factors such as environment and distance to the receiver. Sound power can be calculated from so
38、und pressure or sound intensity determinations. Sound intensity measurements have the following advantages over sound pressure measurements: an intensity meter responds only to the propagating part of a sound field and ignores any non-propagating part, for example, standing waves and reflections; th
39、e intensity method reduces the influence of external sound sources, as long as their sound level is approximately constant. The sound pressure method takes the above factors into account by correcting for background noise and reflections. For a detailed discussion of these measuring techniques, see
40、IEC 60076-1 0-1, Part 10-1: Determination of transformer and reactor sound levels - User guide (under consideration) BSI 5 September 2001 5 EN 60076-10:2001 POWER TRANSFORMERS - Part 10: Determination of sound levels 1 Scope This part of IEC 60076 defines sound pressure and sound intensity measureme
41、nt methods by which sound power levels of transformers, reactors and their associated cooling auxiliaries may be determined. NOTE For the purpose of this standard, the term “transformer“ means “transformer or reactor“. The methods are applicable to transformers and reactors covered by the IEC 60076
42、series, IEC 60289, IEC 60726 and the IEC 61378 series, without limitation as regards size or voltage and when fitted with their normal cooling auxiliaries. This standard is primarily intended to apply to measurements made at the factory. Conditions on-site may be very different because of the proxim
43、ity of objects, including other trans- formers. Nevertheless, the same general rules as are given in this standard may be followed when on-site measurements are made. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisi
44、ons of this part of IEC 60076. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part of IEC 60076 are encouraged to investigate the possibility of applying the most recent editions of the normative d
45、ocuments indicated below. For undated references, the latest edition of the normative document referred to applies. Members of IEC and IS0 maintain registers of currently valid International standards. IEC 60076 (all parts), Power transformers IEC 60289:1988, Reactors IEC 60651:1979, Sound level met
46、ers IEC 60726:1982, Dry-type power transformers IEC 61 043:1993, Electroacoustics - Instruments for the measurement of sound intensity - Measurement with pairs of pressure sensing microphones IEC 61 378 (all parts), Convertor transformers IS0 3746:1995, Acoustics - Determination of sound power level
47、s of noise sources using sound pressure - Survey method using an enveloping measurement surface over a reflecting plane 6 IS0 9614-1:1993, Acoustics - Determination of sound power levels of noise sources using sound intensity - Part 1: Measurement at discrete points BSI 5 September 2001 EN 60076-10:
48、2001 3 Definitions For the purpose of this part of IEC 60076, the definitions in IEC 60076-1, as well as the following definitions, apply. 3.1 sound pressure, p fluctuating pressure superimposed on the static pressure by the presence of sound. It is expressed in pascals 3.2 sound pressure level, Lp
49、ten times the logarithm to the base 10 of the ratio of the square of the sound pressure to the square of the reference sound pressure (Po = 20 x 1 O-6 Pa). It is measured in decibels P2 L, =101g- p,? 3.3 sound intensity, Z vector quantity describing the amount and direction of the net flow of sound energy at a given position. The unit is Wm2 3. 4 normal sound intensity, In component of the sound intensity in the direction normal to a measurement surface 3.5 normal sound intensity level, L, ten times the logarithm to the base 10 of the ratio of the normal sound reference sou
