IEC 61378-1:2011

Converter transformers - Part 1: Transformers for industrial applications

IEC 61378-1:2011 deals with the specification, design and testing of power transformers and reactors which are intended for integration within semiconductor converter plants. The scope of this International Standard is limited to application of power converters of any power rating. Typical applications are:
- thyristor rectifiers for electrolysis;
- diode rectifiers for electrolysis;
- thyristor rectifiers for large drives;
- thyristor rectifiers for scrap melting furnaces, and
- diode rectifiers feeding inverters for variable speed drives. The standard also covers the regulating unit utilized in such application as step down regulating transformers or autotransformers. This edition includes the following significant technical changes with respect to the previous edition:
- addition of winding connections with phase displacement (30°);
- addition of transformers with more than one active part in the same tank;
- change of reference power definition;
- addition of regulating transformer feeding converter transformer;
- addition of considerations about current sharing and hot spot temperature in high current windings for various winding arrangements;
- addition of transductors used for d.c. voltage regulation together with diode rectifiers. The contents of the corrigendum of January 2012 have been included in this copy.

Transformateurs de conversion - Partie 1: Transformateurs pour applications industrielles

L'IEC 61378-1:2011 traite de la spécification, la conception et l'essai des transformateurs de puissance et des réacteurs qui sont destinés à l'intégration au sein des convertisseurs à semi-conducteurs, il n'est pas applicable aux transformateurs conçus pour la distribution industrielle ou publique de pouvoir a.c. en général. Cette édition inclut les changements techniques significatifs suivants par rapport à la précédente édition:
- Addition de couplages d'enroulements (zigzag, triangle prolongé, etc.) avec déphasage ( - Addition de transformateurs ayant plus d'une partie active dans la même cuve.
- Changement de la définition de la puissance de référence (elle est désormais basée sur la composante fondamentale du courant).
- Addition de considérations pour des lignes directrices relatives à la sélection de changeurs de prise en charge (OLTC, On-Load Tap-Changers).
- Addition du transformateur de régulation alimentant un transformateur de conversion.
- Addition de considérations relatives à la répartition des courants et aux points chauds dans les enroulements à fort courant pour diverses dispositions d'enroulements.
- Addition de transducteurs magnétiques pour la régulation de tension continue avec des redresseurs à diodes.
- Amélioration des anciennes annexes avec plusieurs exemples de calcul.
- Additions de nouvelles annexes pour les montages de mesure spéciaux.

General Information

• Status: Published
• Publication Date: 25-Jul-2011
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 29.180 - Transformers. Reactors
• Technical Committee: TC 14 - Power transformers
• Drafting Committee: MT 7 - TC 14/MT 7
• Current Stage: PPUB - Publication issued
• Start Date: 15-Aug-2011
• Completion Date: 26-Jul-2011

Relations

• Corrected By: IEC 61378-1:2011/COR1:2012 - Corrigendum 1 - Converter transformers - Part 1: Transformers for industrial applications
• Effective Date: 05-Sep-2023
• Revises: IEC 61378-1:1997 - Convertor transformers - Part 1: Transformers for industrial applications
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61378-1 ®
Edition 2.0 2011-07
INTERNATIONAL
STANDARD
colour
inside
Converter transformers –
Part 1: Transformers for industrial applications

All rights reserved. Unless otherwise specified, 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
either IEC or IEC's member National Committee in the country of the requester.
If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication,
please contact the address below or your local IEC member National Committee for further information.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: [e-mail]
Web: www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.
 Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
 IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
 Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
 Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: [e-mail]
Tel.: [phone]
Fax: [phone]
IEC 61378-1 ®
Edition 2.0 2011-07
INTERNATIONAL
STANDARD
colour
inside
Converter transformers –
Part 1: Transformers for industrial applications

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XC
ICS 29.180 ISBN 978-2-88912-602-6

– 2 – 61378-1 © IEC:2011(E)
CONTENTS
FOREWORD . 6
1 Scope . 8
2 Normative references. 9
3 Terms, definitions and acronyms . 9
3.1 Terms and definitions . 9
3.2 Acronyms . 10
4 Classification . 11
4.1 General . 11
4.2 Normal service conditions . 11
4.3 Provision for unusual service conditions . 12
5 Ratings . 12
5.1 General . 12
5.2 Rated power at rated frequency and load capability . 12
5.3 Rated and service voltages . 13
5.3.1 Transformer energized from an a.c. power system . 13
5.3.2 Transformer energized from a converter/inverter with or without
variable frequency . 13
5.4 Rated current . 13
5.5 Phase displacement and terminal identification for three-phase transformer . 13
5.6 Rating plate . 14
5.7 Units with tertiary windings loaded with filter and compensation . 14
5.8 On load tap-changers . 15
6 Load loss and voltage drop in transformers and reactors . 15
6.1 General . 15
6.2 Determination of transformer load loss under distorted current loading . 15
6.3 Current sharing, losses and hot spot in high current windings . 19
6.4 Effect of geometrical winding arrangement and magnetic coupling between
windings on their eddy current losses due to harmonics in transformers with
three or more windings wound on the same core limb . 20
6.5 Losses in interphase transformers, current-balancing reactors, series-
smoothing reactors and transductors . 26
6.5.1 General . 26
6.5.2 Interphase transformers . 26
6.5.3 Current-balancing reactors . 26
6.5.4 Series-smoothing reactors . 26
6.5.5 Transductors . 26
6.6 Voltage drops in transformers and reactors . 27
6.6.1 General . 27
6.6.2 Transductors . 28
7 Tests for converter transformers . 29
7.1 General . 29
7.2 Measurement of commutating reactance and determination of the inductive
voltage drop . 30
7.2.1 Commutating reactance . 30
7.2.2 Inductive voltage regulation . 30
7.3 Measurement of voltage ratio and phase displacement . 31
7.4 Dielectric tests . 31

61378-1 © IEC:2011(E) – 3 –
7.4.1 General . 31
7.4.2 Dielectric test between interleaved valve windings . 31
7.5 Load loss test . 32
7.5.1 General . 32
7.5.2 Load loss measurement in rectifier transformers with transductors in
the same tank . 32
7.5.3 Test bus bars configuration for short circuit of high current valve
windings . 32
7.6 Temperature rise tests . 32
7.6.1 General . 32
7.6.2 Total loss injection . 33
7.6.3 Rated load loss injection . 33
7.6.4 Test of temperature rise on dry-type transformers . 35
8 On load noise level with transductors and/or IPT . 35
Annex A (informative) Determination of transformer service load loss at rated non-
sinusoidal converter current from measurements with rated transformer current
of fundamental frequency . 38
Annex B (informative) Short-circuit test currents and load losses in transformers for
single-way converters (total loss injection) . 56
Annex C (informative) Current sharing measurement in high current valve windings . 57
Annex D (informative) Examples of duty cycles . 66
Annex E (informative) Guidelines for design review . 67
Annex F (informative) Determination of loss in transformer tank due to magnetic field.
3D simulation and guidelines for tank losses evaluation and tank hotspot
calculation . 70
Annex G (informative) Short-circuit measurements of rectifier transformers equipped
with built in transductors . 71
Annex H (informative) Determination of the transformer voltage ratio and phase
displacement by the turn ratio measurements . 73
Annex I (informative) Phase displacement connections and terminal indications of
converter transformers . 78
Annex J (normative) Correlation between IEC 61378-1 and IEC 60146-1-1 ratings . 83
Bibliography . 90

Figure 1 – B6U or DB 6 pulse double bridge connection . 10
Figure 2 – DSS 6 pulse connection . 11
Figure 3 – Leakage fields for a three-winding transformer with closely coupled valve
windings. 22
Figure 4 – Leakage fields for a three-winding transformer with decoupled valve
windings. 23
Figure 5 – Leakage fields for a three winding transformer with loosely coupled double
concentric valve windings . 24
Figure 6 – Leakage fields for a three winding transformer with loosely coupled double-
tier valve windings . 25
Figure 7 – Typical transductor regulating curve (with max voltage drop at zero control
current) and tolerance band . 28
Figure A.1 – Cross-section of a winding strand . 40
Figure A.2 – Terminal identification for winding connection Y y0y6 . 43
Figure A.3 – Terminal identification for winding connection D d0y1 . 46

– 4 – 61378-1 © IEC:2011(E)
Figure A.4 – Valve current DB connection rectangular shape positive shape . 47
Figure A.5 – Valve current DB connection rectangular shape positive and negative
shape. 48
Figure A.6 – Valve current DSS connection rectangular shape . 52
Figure C.1 – Example of valve high current winding and measurement equipment
disposition . 58
Figure C.2 – Transformer windings arrangement . 59
Figure C.3 – Measurement circuit for the in-phase measurement . 60
Figure C.4 – Measurement circuit for the in-opposition measurement. 61
Figure C.5 – Measurements and comparison with the simulations made by finite
element method software for the in-phase current distribution . 63
Figure C.6 – Measurements and comparison with the simulations made by finite
element method software fo
...

IEC 61378-1 ®
Edition 2.0 2011-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Converter transformers –
Part 1: Transformers for industrial applications

Transformateurs de conversion -
Partie 1: Transformateurs pour applications industrielles

All rights reserved. Unless otherwise specified, 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
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: [phone]
3, rue de Varembé Fax: [phone]
CH-1211 Geneva 20 [e-mail]
Switzerland www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing more than 30 000 terms and
Technical Specifications, Technical Reports and other definitions in English and French, with equivalent terms in 14
documents. Available for PC, Mac OS, Android Tablets and additional languages. Also known as the International
iPad. Electrotechnical Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a More than 55 000 electrotechnical terminology entries in
variety of criteria (reference number, text, technical English and French extracted from the Terms and Definitions
committee,…). It also gives information on projects, replaced clause of IEC publications issued since 2002. Some entries
and withdrawn publications. have been collected from earlier publications of IEC TC 37,

77, 86 and CISPR.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: [e-mail].
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.

Catalogue IEC - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
Application autonome pour consulter tous les renseignements
Le premier dictionnaire en ligne de termes électroniques et
bibliographiques sur les Normes internationales,
électriques. Il contient plus de 30 000 termes et définitions en
Spécifications techniques, Rapports techniques et autres
anglais et en français, ainsi que les termes équivalents dans
documents de l'IEC. Disponible pour PC, Mac OS, tablettes
14 langues additionnelles. Egalement appelé Vocabulaire
Android et iPad.
Electrotechnique International (IEV) en ligne.

Recherche de publications IEC - www.iec.ch/searchpub
Glossaire IEC - std.iec.ch/glossary
Plus de 55 000 entrées terminologiques électrotechniques, en
La recherche avancée permet de trouver des publications IEC
en utilisant différents critères (numéro de référence, texte, anglais et en français, extraites des articles Termes et
comité d’études,…). Elle donne aussi des informations sur les Définitions des publications IEC parues depuis 2002. Plus
projets et les publications remplacées ou retirées. certaines entrées antérieures extraites des publications des

CE 37, 77, 86 et CISPR de l'IEC.
IEC Just Published - webstore.iec.ch/justpublished

Service Clients - webstore.iec.ch/csc
Restez informé sur les nouvelles publications IEC. Just
Published détaille les nouvelles publications parues. Si vous désirez nous donner des commentaires sur cette
Disponible en ligne et aussi une fois par mois par email. publication ou si vous avez des questions contactez-nous:
[e-mail].
IEC 61378-1 ®
Edition 2.0 2011-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Converter transformers –
Part 1: Transformers for industrial applications

Transformateurs de conversion -

Partie 1: Transformateurs pour applications industrielles

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XC
ICS 29.180 ISBN 978-2-8322-1698-9

– 2 – IEC 61378-1:2011 © IEC 2011
CONTENTS
FOREWORD . 6
1 Scope . 8
2 Normative references. 9
3 Terms, definitions and acronyms . 9
3.1 Terms and definitions . 9
3.2 Acronyms . 10
4 Classification . 11
4.1 General . 11
4.2 Normal service conditions . 11
4.3 Provision for unusual service conditions . 12
5 Ratings . 12
5.1 General . 12
5.2 Rated power at rated frequency and load capability . 12
5.3 Rated and service voltages . 13
5.3.1 Transformer energized from an a.c. power system . 13
5.3.2 Transformer energized from a converter/inverter with or without
variable frequency . 13
5.4 Rated current . 13
5.5 Phase displacement and terminal identification for three-phase transformer . 13
5.6 Rating plate . 14
5.7 Units with tertiary windings loaded with filter and compensation . 14
5.8 On load tap-changers . 15
6 Load loss and voltage drop in transformers and reactors . 15
6.1 General . 15
6.2 Determination of transformer load loss under distorted current loading . 15
6.3 Current sharing, losses and hot spot in high current windings . 19
6.4 Effect of geometrical winding arrangement and magnetic coupling between
windings on their eddy current losses due to harmonics in transformers with
three or more windings wound on the same core limb . 20
6.5 Losses in interphase transformers, current-balancing reactors, series-
smoothing reactors and transductors . 26
6.5.1 General . 26
6.5.2 Interphase transformers . 26
6.5.3 Current-balancing reactors . 26
6.5.4 Series-smoothing reactors . 26
6.5.5 Transductors . 26
6.6 Voltage drops in transformers and reactors . 27
6.6.1 General . 27
6.6.2 Transductors . 28
7 Tests for converter transformers . 29
7.1 General . 29
7.2 Measurement of commutating reactance and determination of the inductive
voltage drop . 30
7.2.1 Commutating reactance . 30
7.2.2 Inductive voltage regulation . 30
7.3 Measurement of voltage ratio and phase displacement . 31
7.4 Dielectric tests . 31

7.4.1 General . 31
7.4.2 Dielectric test between interleaved valve windings . 31
7.5 Load loss test . 32
7.5.1 General . 32
7.5.2 Load loss measurement in rectifier transformers with transductors in
the same tank . 32
7.5.3 Test bus bars configuration for short circuit of high current valve
windings . 32
7.6 Temperature rise tests . 32
7.6.1 General . 32
7.6.2 Total loss injection . 33
7.6.3 Rated load loss injection . 33
7.6.4 Test of temperature rise on dry-type transformers . 35
8 On load noise level with transductors and/or IPT . 35
Annex A (informative) Determination of transformer service load loss at rated non-
sinusoidal converter current from measurements with rated transformer current
of fundamental frequency . 38
Annex B (informative) Short-circuit test currents and load losses in transformers for
single-way converters (total loss injection) . 56
Annex C (informative) Current sharing measurement in high current valve windings . 57
Annex D (informative) Examples of duty cycles . 66
Annex E (informative) Guidelines for design review . 67
Annex F (informative) Determination of loss in transformer tank due to magnetic field.
3D simulation and guidelines for tank losses evaluation and tank hotspot calculation . 70
Annex G (informative) Short-circuit measurements of rectifier transformers equipped
with built in transductors .
...