IEC 60076-10:2001

Power transformers - Part 10: Determination of sound levels

Defines sound pressure and sound intensity measurement methods by which sound power levels of transformers, reactors and their associated cooling auxiliaries may be determined. Is applicable to transformers and reactors covered by the IEC 60076 series, IEC 60289, and the IEC 61378 series, without limitation as regards size or voltage and when fitted with their normal cooling auxiliaries.

Transformateurs de puissance - Partie 10: Détermination des niveaux de bruit

Définit les méthodes de mesure de la pression acoustique et de l'intensité acoustique par lesquelles peuvent être déterminés les niveaux de puissance acoustique des transformateurs, bobines d'inductance et leurs auxiliaires de refroidissement associés. Est applicable aux transformateurs et bobines d'inductance couverts par la série CEI 60076, la CEI 60289, et la série CEI 61378, sans limite quant à la taille ou la tension et lorsqu'ils sont adaptés aux auxiliaires de refroidissement normaux.

General Information

• Status: Published
• Publication Date: 21-May-2001
• ICS: 29.180 - Transformers. Reactors
• Technical Committee: TC 14 - Power transformers
• Drafting Committee: WG 25 - TC 14/WG 25
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 24-Mar-2016

Relations

• Revised: IEC 60076-10:2016 - Power transformers - Part 10: Determination of sound levels
• Effective Date: 05-Sep-2023

Standards Content (Sample)

INTERNATIONAL IEC
STANDARD
60076-10
First edition
2001-05
Power transformers –
Part 10:
Determination of sound levels
Transformateurs de puissance –
Partie 10:
Détermination des niveaux de bruit
Reference number
Publication numbering
As from 1 January 1997 all IEC publications are issued with a designation in the
60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1.
Consolidated editions
The IEC is now publishing consolidated versions of its publications. For example,
edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the base publication, the
base publication incorporating amendment 1 and the base publication incorporating
amendments 1 and 2.
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INTERNATIONAL IEC
STANDARD
60076-10
First edition
2001-05
Power transformers –
Part 10:
Determination of sound levels
Transformateurs de puissance –
Partie 10:
Détermination des niveaux de bruit
 IEC 2001  Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: [phone] e-mail: [e-mail] IEC web site http://www.iec.ch
Commission Electrotechnique Internationale
PRICE CODE
Q
International Electrotechnical Commission
For price, see current catalogue

– 2 – 60076-10  IEC:2001(E)
CONTENTS
FOREWORD.3
INTRODUCTION.5
1 Scope.7
2 Normative references .7
3 Definitions .8
4 Instrumentation and calibration.9
5 Choice of test method.9
6 Load conditions .9
6.1 General .9
6.2 No-load current and rated voltage .10
6.3 Rated current and short-circuit voltage .10
6.4 Reduced-load current .11
7 Principal radiating surface .11
7.1 General .11
7.2 Transformers with or without cooling auxiliaries, dry-type transformers in enclosures
and dry-type transformers with cooling auxiliaries inside the enclosure .11
7.3 Cooling auxiliaries mounted on a separate structure spaced ≥3 m away from
the principal radiating surface of the transformer.11
7.4 Dry-type transformers without enclosures.11
8 Prescribed contour .12
9 Microphone positions.12
10 Calculation of the area of the measurement surface .12
10.1 Measurements made at 0,3 m from the principal radiating surface.12
10.2 Measurements made at 2 m from the principal radiating surface.13
10.3 Measurements made at 1 m from the principal radiating surface.13
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 provisions of 10.1 to 10.3.13
11 Sound pressure method.13
11.1 Test environment.13
11.2 Sound pressure level measurements .16
11.3 Calculation of average sound pressure level .16
12 Sound intensity method .18
12.1 Test environment.18
12.2 Sound intensity level measurements.18
12.3 Calculation of average sound intensity level .18
13 Calculation of sound power level .19
14 Addition of no-load and load current sound power levels .20
15 Far-field calculations .20
16 Presentation of results.20
Annex A (informative) Narrow-band and time-synchronous measurements .29
Annex B (informative) Typical report of sound level determination .31

60076-10  IEC:2001(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
POWER TRANSFORMERS –
Part 10: Determination of sound levels
FOREWORD
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all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
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5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60076-10 has been prepared by IEC technical committee 14:
Power transformers.
This first edition of IEC 60076-10 cancels and replaces IEC 60551, published in 1987 and its
amendment 1 (1995), and constitutes a technical revision.
The text of this standard is based on the following documents:
FDIS Report on voting
14/390/FDIS 14/394/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 3.
Annexes A and B are for information only.
IEC 60076 consists of the following parts, under the general title: Power transformers.
Part 1: General
Part 2: Temperature rise
Part 3: Insulation levels, dielectric tests and external clearances in air

– 4 – 60076-10  IEC:2001(E)
Part 5: Ability to withstand short-circuit
Part 8: Application guide
Part 10: Determination of sound levels
The committee has decided that the contents of this publication will remain unchanged until
2008. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

60076-10  IEC:2001(E) – 5 –
INTRODUCTION
One of the many parameters to be considered when designing and siting transformers,
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 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 magnetic 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.
Current 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 power 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 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 tolerances 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 should 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 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 sound
Sound level measurements have been developed to quantify pressure variations in air that a
human ear can detect. The smallest pressure variation that a healthy human ear can detect is
20 μPa. This is the reference level (0 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
frequency 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 common.
Sound intensity is defined as the rate of e
...

IEC 60076-10
Edition 1.0 2001-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Power transformers –
Part 10: Determination of sound levels

Transformateurs de puissance –
Partie 10: Détermination des niveaux de bruit

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IEC 60076-10
Edition 1.0 2001-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Power transformers –
Part 10: Determination of sound levels

Transformateurs de puissance –
Partie 10: Détermination des niveaux de bruit

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
V
CODE PRIX
ICS 29.180 ISBN 2-8318-8109-9
– 2 – 60076-10  CEI:2001
SOMMAIRE
AVANT-PROPOS.4
INTRODUCTION.8
1 Domaine d'application .12
2 Références normatives.12
3 Termes et définitions .14
4 Instrumentation et étalonnage .16
5 Choix de la méthode d'essai.16
6 Conditions de charge.18
6.1 Généralités.18
6.2 Courant à vide et tension assignée.18
6.3 Courant assigné et tension de court-circuit.18
6.4 Courant de charge réduite.20
7 Surface de rayonnement principale.20
7.1 Généralités.20
7.2 Transformateurs avec ou sans auxiliaire de refroidissement, transformateurs
de type sec dans des enveloppes et transformateurs de type sec avec
auxiliaires de refroidissement à l'intérieur de l'enveloppe .20
7.3 Auxiliaires de refroidissement montés sur une structure séparée espacée à
une distance ≥3 m de la surface de rayonnement principale du
transformateur.22
7.4 Transformateurs de type sec sans enveloppes .22
8 Contour prescrit.22
9 Positions de microphone .22
10 Calcul de la zone de la surface de mesure .24
10.1 Mesures effectuées à 0,3 m de la surface de rayonnement principale .24
10.2 Mesures effectuées à 2 m de la surface de rayonnement principale .24
10.3 Mesures effectuées à 1 m de la surface de rayonnement principale .24
10.4 Mesures sur des objets d'essai où les considérations de distance de sécurité
exigent une distance de mesure qui pour tout ou partie des contours
prescrits dépasse les dispositions de 10.1 à 10.3 .24
11 Méthode de pression acoustique .26
11.1 Environnement d'essai .26
11.2 Mesures du niveau de la pression acoustique .30
11.3 Calcul du niveau de pression acoustique moyen.32
12 Méthode d'intensité acoustique.34
12.1 Environnement d'essai .34
12.2 Mesures du niveau d'intensité acoustique .36
12.3 Calcul du niveau d'intensité acoustique moyen.36
13 Calcul du niveau de puissance acoustique .38
14 Ajout des niveaux de puissance acoustique à courant à vide et de charge .38
15 Calculs en champ lointain.40
16 Présentation des résultats .40

Annexe A (informative)  Mesures à bande étroite et temps synchrone.56
Annexe B (informative) Rapport type de la détermination du niveau acoustique.60

60076-10  IEC:2001 – 3 –
CONTENTS
FOREWORD.5
INTRODUCTION.9
1 Scope.13
2 Normative references .13
3 Terms and definitions .15
4 Instrumentation and calibration.17
5 Choice of test method.17
6 Load conditions .19
6.1 General .19
6.2 No-load current and rated voltage .19
6.3 Rated current and short-circuit voltage .19
6.4 Reduced-load current .21
7 Principal radiating surface .21
7.1 General .21
7.2 Transformers with or without cooling auxiliaries, dry-type transformers in
enclosures and dry-type transformers with cooling auxiliaries inside the
enclosure .21
7.3 Cooling auxiliaries mounted on a separate structure spaced ≥3 m away from
the principal radiating surface of the transformer.23
7.4 Dry-type transformers without enclosures.23
8 Prescribed contour .23
9 Microphone positions.23
10 Calculation of the area of the measurement surface .25
10.1 Measurements made at 0,3 m from the principal radiating surface.25
10.2 Measurements made at 2 m from the principal radiating surface.25
10.3 Measurements made at 1 m from the principal radiating surface.25
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 provisions of 10.1 to 10.3 .25
11 Sound pressure method.27
11.1 Test environment.27
11.2 Sound pressure level measurements .31
11.3 Calculation of average sound pressure level .33
12 Sound intensity method .35
12.1 Test environment.35
12.2 Sound intensity level measurements .37
12.3 Calculation of average sound intensity level .37
13 Calculation of sound power level .39
14 Addition of no-load and load current sound power levels .39
15 Far-field calculations .4
...