Power transformers - Part 11: Dry-type transformers

NEW!IEC 60076-11:2018 is available as IEC 60076-11:2018 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC 60076-11:2018 applies to dry-type power transformers (including auto-transformers) having values of highest voltage for equipment up to and including 72,5 kV and at least one winding operating at greater than 1,1 kV. This document does not apply to: - gas-filled dry-type transformers where the gas is not air; - single-phase transformers rated at less than 5 kVA; - polyphase transformers rated at less than 15 kVA; - instrument transformers; - starting transformers; - testing transformers; - traction transformers mounted on rolling stock; - flameproof and mining transformers; - welding transformers; - voltage regulating transformers; - small power transformers in which safety is a special consideration. Where IEC standards do not exist for the transformers mentioned above or for other special transformers, this document may be applicable as a whole or in parts. This second edition cancels and replaces the first edition published in 2004 and constitutes a technical revision. The main changes with regard to the previous edition are as follows: - Extension of the scope up to 72,5kV - Enclosure management in regards of the performance - Management of the dielectric and thermal features with altitude - New climatic classes for a better adaptation of customers’ need - Establishment of the relation between location and environmental classes - For fire behaviour classes, limitation at 1000kVA and process of test more robust - Introduction of Seismic class - Recommendations for amorphous transformers Keywords: dry-type transformers

Leistungstransformatoren - Teil 11: Trockentransformatoren

Transformateurs de puissance - Partie 11: Transformateurs de type sec

NEW!IEC 60076-11:2018 est disponible sous forme de IEC 60076-11:2018 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.L'IEC 60076-11:2018 applique aux transformateurs de type sec (y compris les autotransformateurs) dont les valeurs de tension la plus élevée pour le matériel sont inférieures ou égales à 72,5 kV avec au moins un enroulement fonctionnant à plus de 1,1 kV. Le présent document ne s'applique pas aux: - transformateurs de type sec avec un diélectrique gazeux autre que l'air; - transformateurs monophasés de moins de 5 kVA; - transformateurs polyphasés de moins de 15 kVA; - transformateurs de mesure; - transformateurs de démarrage; - transformateurs d'essai; - transformateurs de traction montés sur matériel roulant; - transformateurs antidéflagrants et de mines; - transformateurs de soudure; - transformateurs de réglage de tension; - petitstransformateurs de puissance pour lesquels la sécurité est spécialement à prendre en compte. Lorsqu'il n'existe pas de norme IEC pour les transformateurs mentionnés ci-dessus ou pour d'autres transformateurs spéciaux, le présent document peut être appliquée en tout ou en partie. Cette deuxième édition annule et remplace la première édition publiée en 2004 dont elle constitue une révision technique. Les principales modifications par rapport à l'édition précédente sont les suivantes: - Extension du domaine d'application jusqu'à 72,5 kV - Prise en compte des enveloppes en ce qui concerne les performances - Prise en compte des caractéristiques diélectriques et thermiques en fonction de l'altitude - Nouvelles classes climatiques pour une meilleure adaptation des besoins des clients - Établissement de la relation entre l'emplacement et les classes d'environnement - Pour les classes de comportement au feu, limitation à 1 000 kVA et processus d'essai plus robuste - Introduction d'une classe sismique - Recommandations pour les transformateurs amorphes Mots-clés: transformateurs de type sec

Močnostni transformatorji - 11. del: Suhi transformatorji

Ta del standarda IEC 60076 se uporablja za suhe močnostne transformatorje (vključno z avtotransformatorji) z vrednostmi najvišje napetosti opreme največ 72,5 kV in vsaj enim navitjem, ki deluje pri več kot 1,1 kV.
Ta dokument se ne uporablja za:
• plinske suhe transformatorje, pri katerih plin ni zrak;
• enofazne transformatorje z nazivno vrednostjo manj kot 5 kVA;
• večfazne transformatorje z nazivno vrednostjo manj kot 15 kVA;
• instrumentne transformatorje;
• zagonske transformatorje;
• preskusne transformatorje;
• transformatorje vleke, nameščene na železniška vozila;
• ognjevarne in rudarske transformatorje;
• varilne transformatorje;
• transformatorje za regulacijo napetosti;
• majhne močnostne transformatorje, pri katerih veljajo posebne zahteve za varnost.
Če standardi IEC za zgoraj omenjene transformatorje ali druge posebne transformatorje niso na voljo, se lahko ta dokument uporablja v celoti ali delno.

General Information

Status
Published
Publication Date
25-Oct-2018
Technical Committee
Drafting Committee
Current Stage
6060 - Document made available
Due Date
12-Feb-2019

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SLOVENSKI STANDARD
SIST EN IEC 60076-11:2019
01-januar-2019
1DGRPHãþD
SIST EN 60076-11:2005
0RþQRVWQLWUDQVIRUPDWRUMLGHO6XKLWUDQVIRUPDWRUML
Power transformers - Part 11: Dry-type transformers
Leistungstransformatoren - Teil 11: Trockentransformatoren
Transformateurs de puissance - Partie 11: Transformateurs de type sec
Ta slovenski standard je istoveten z: EN IEC 60076-11:2018
ICS:
29.180 Transformatorji. Dušilke Transformers. Reactors
SIST EN IEC 60076-11:2019 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN IEC 60076-11:2019
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SIST EN IEC 60076-11:2019
EUROPEAN STANDARD EN IEC 60076-11
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2018
ICS 29.180 Supersedes EN 60076-11:2004
English Version
Power transformers - Part 11: Dry-type transformers
(IEC 60076-11:2018)

Transformateurs de puissance - Partie 11: Transformateurs Leistungstransformatoren - Teil 11: Trockentransformatoren

de type sec (IEC 60076-11:2018)
(IEC 60076-11:2018)

This European Standard was approved by CENELEC on 2018-09-19. 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 national 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 own 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,

Switzerland, Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2018 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN IEC 60076-11:2018 E
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SIST EN IEC 60076-11:2019
EN IEC 60076-11:2018 (E)
European foreword

The text of document 14/964/FDIS, future edition 2 of IEC 60076-11, prepared by IEC/TC 14 "Power

transformers" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as

EN IEC 60076-11:2018.
The following dates are fixed:

• latest date by which the document has to be implemented at national (dop) 2019-06-19

level by publication of an identical national standard or by endorsement

• latest date by which the national standards conflicting with the (dow) 2021-09-19

document have to be withdrawn
This document supersedes EN 60076-11:2004.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Endorsement notice

The text of the International Standard IEC 60076-11:2018 was approved by CENELEC as a European

Standard without any modification.

In the official version, for Bibliography, the following notes have to be added for the standards

indicated:
IEC 60721-2-6:1990 NOTE Harmonized as HD 478.2.6 S1:1993 (not modified)
ISO 12944-2 NOTE Harmonized as EN ISO 12944-2
ISO 12944 (series) NOTE Harmonized as EN ISO 12944 (series)
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SIST EN IEC 60076-11:2019
EN IEC 60076-11:2018 (E)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments)

applies.

NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the relevant

EN/HD applies.

NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:

www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60068-3-3 - Environmental testing - Part 3-3: Guidance - EN 60068-3-3 -
Seismic test methods for equipments
IEC 60071-1 - Insulation co-ordination - Part 1: Definitions, EN 60071-1 -
principles and rules

IEC 60071-2 - Insulation co-ordination – Part 2: Application EN IEC 60071-2 -

guidelines
IEC 60076-1 2011 Power transformers - Part 1: General EN 60076-1 2011
IEC 60076-2 - Power transformers - Part 2: Temperature rise EN 60076-2 -
for liquid-immersed transformers

IEC 60076-3 2013 Power transformers - Part 3: Insulation levels, EN 60076-3 2013

dielectric tests and external clearances in air
IEC 60076-5 - Power transformers - Part 5: Ability to withstand EN 60076-5 -
short circuit
IEC 60076-10 - Power transformers - Part 10: Determination of EN 60076-10 -
sound levels
IEC 60076-12 2008 Power transformers - Part 12: Loading guide for - -
dry-type power transformers
IEC 60085 - Electrical insulation - Thermal evaluation and EN 60085 -
designation
IEC 60270 - High-voltage test techniques - Partial discharge EN 60270 -
measurements

IEC 60332-3-10 - Tests on electric cables under fire conditions - EN IEC 60332-3- -

Part 3-10: Test for vertical flame spread of 10
vertically-mounted bunched wires or cables -
Apparatus
IEC 60529 - Degrees of protection provided by enclosures - -
(IP Code)
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SIST EN IEC 60076-11:2019
EN IEC 60076-11:2018 (E)

IEC 60721-3-4 - Classification of environmental conditions - Part EN 60721-3-4 -

3: Classification of groups of environmental
parameters and their severities - Section 4:
Stationary use at non-weatherprotected
locations
IEC/TS 60815-1 - Selection and dimensioning of high-voltage EN 61378-1 -
insulators intended for use in polluted
conditions - Part 1: Definitions, information and
general principles
IEC 61378-1 - Converter transformers - Part 1: Transformers EN 61378-1 -
for industrial applications

IEC 62271-202 - High-voltage switchgear and controlgear - Part EN 62271-202 -

202: High-voltage/ low-voltage prefabricated
substation

ISO 12944-6 - Paints and varnishes - Corrosion protection of EN ISO 12944-6 -

steel structures by protective paint systems -
Part 6: Laboratory performance test methods
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SIST EN IEC 60076-11:2019
IEC 60076-11
Edition 2.0 2018-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Power transformers –
Part 11: Dry-type transformers
Transformateurs de puissance –
Partie 11: Transformateurs de type sec
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.180 ISBN 978-2-8322-5910-8

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
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SIST EN IEC 60076-11:2019
– 2 – IEC 60076-11:2018 © IEC 2018
CONTENTS

FOREWORD ......................................................................................................................... 6

1 Scope ............................................................................................................................ 8

2 Normative references..................................................................................................... 8

3 Terms and definitions .................................................................................................... 9

4 Service conditions ....................................................................................................... 10

4.1 General ............................................................................................................... 10

4.2 Normal service conditions ................................................................................... 10

4.3 Electromagnetic compatibility (EMC) .................................................................... 11

5 Rating and general requirements ................................................................................. 12

5.1 General ............................................................................................................... 12

5.2 Rated power ....................................................................................................... 12

5.2.1 General ....................................................................................................... 12

5.2.2 Definition of the rated power with fans cooling or heat exchangers ................ 12

5.2.3 Transformer IP00 (without enclosure) ........................................................... 12

5.2.4 Transformer with enclosure .......................................................................... 12

5.2.5 Preferred values of rated power .................................................................... 13

5.2.6 Loading beyond rated power ........................................................................ 13

5.3 Provision for unusual service conditions .............................................................. 13

5.4 Transportation and storage .................................................................................. 14

5.4.1 Transport limitation ...................................................................................... 14

5.4.2 Transport acceleration ................................................................................. 14

5.4.3 Temperature and environment conditions for transport and storage ............... 14

5.5 Rated voltage and rated frequency ...................................................................... 15

5.5.1 Rated voltage .............................................................................................. 15

5.5.2 Rated frequency ........................................................................................... 15

5.6 Operation at higher than rated voltage ................................................................. 15

5.7 Highest voltage for equipment U and dielectric tests levels ................................ 15

5.8 Identification according to cooling method ........................................................... 15

5.8.1 General ....................................................................................................... 15

5.8.2 Identification symbols ................................................................................... 15

5.8.3 Arrangement of symbols ............................................................................... 16

5.9 Guaranteed temperature rise at rated conditions .................................................. 16

5.10 Additional information required for enquiry ........................................................... 16

5.11 Sound level ......................................................................................................... 16

5.12 Components and materials .................................................................................. 16

6 Tappings ..................................................................................................................... 16

7 Connections ................................................................................................................ 17

8 Ability to withstand short circuit .................................................................................... 17

9 Rating plate ................................................................................................................. 17

9.1 Rating plate fitted to the transformer .................................................................... 17

9.2 Rating plate fitted to the transformer enclosure .................................................... 18

10 Temperature-rise limits ................................................................................................ 18

10.1 Normal temperature-rise limits ............................................................................. 18

10.2 Reduced temperature rises for transformers designed for high cooling

medium temperatures or special cooling medium conditions ................................. 19

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10.3 High altitude temperature rise correction .............................................................. 19

11 Insulation levels ........................................................................................................... 19

11.1 General ............................................................................................................... 19

11.2 Transformers for use at high altitudes .................................................................. 20

12 Climatic, environmental and fire behaviour classes ....................................................... 21

12.1 Climatic classes .................................................................................................. 21

12.2 Environmental classes ......................................................................................... 21

12.2.1 Transformers for indoor application with or without enclosure and for

outdoor application with enclosure ................................................................ 21

12.2.2 Dry-type transformers without enclosure for outdoor application .................... 22

12.3 Fire behaviour classes ........................................................................................ 22

12.4 Test criteria for climatic, environmental and fire behaviour classes ....................... 23

13 Seismic ....................................................................................................................... 23

13.1 General ............................................................................................................... 23

13.2 General seismic class approach .......................................................................... 24

13.2.1 Generalities ................................................................................................. 24

13.2.2 The standard amplitude method ................................................................... 24

13.2.3 The calculated amplitude method ................................................................. 25

14 Test ............................................................................................................................ 26

14.1 General requirements for tests ............................................................................ 26

14.2 Routine tests ....................................................................................................... 27

14.2.1 Measurement of winding resistance .............................................................. 27

14.2.2 Measurement of voltage ratio and check of phase displacement .................... 27

14.2.3 Measurement of short-circuit impedance and load loss ................................. 27

14.2.4 Measurement of no-load loss and current ..................................................... 28

14.2.5 Applied voltage test (AV) .............................................................................. 28

14.2.6 Induced voltage withstand test (IVW) ............................................................ 28

14.2.7 Partial discharge measurement .................................................................... 28

14.3 Type tests ........................................................................................................... 30

14.3.1 Full wave lightning impulse test (LI) .............................................................. 30

14.3.2 Temperature-rise test ................................................................................... 31

14.4 Special tests ....................................................................................................... 34

14.4.1 Partial discharge measurement for transformers operated under a

single phase line-to-earth fault condition ....................................................... 34

14.4.2 Measurement of sound level ......................................................................... 35

14.4.3 Short-circuit test........................................................................................... 35

14.4.4 Climatic tests ............................................................................................... 35

14.4.5 Environmental test ....................................................................................... 37

14.4.6 Fire behaviour test ....................................................................................... 39

14.4.7 Seismic test ................................................................................................. 45

14.4.8 Special test for transformers equipped with amorphous core ......................... 46

15 Tolerances .................................................................................................................. 46

16 Protection against direct contact .................................................................................. 47

17 Degrees of protection provided by enclosures .............................................................. 47

18 Earthing terminal ......................................................................................................... 47

19 Information required with enquiry and order .................................................................. 47

Annex A (informative) Installation and safety of dry-type transformers ................................. 48

A.1 Manuals .............................................................................................................. 48

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SIST EN IEC 60076-11:2019
– 4 – IEC 60076-11:2018 © IEC 2018

A.2 Installation .......................................................................................................... 48

A.2.1 General ....................................................................................................... 48

A.2.2 Intrinsic safety ............................................................................................. 48

A.2.3 Installation precautions ................................................................................ 48

A.2.4 Installation design ........................................................................................ 49

Annex B (informative) Environmental test for evaluation of outdoor transformers

without enclosure ................................................................................................................ 50

B.1 General ............................................................................................................... 50

B.2 Salt-fog and UV-radiation chamber test ............................................................... 50

B.2.1 Test description ........................................................................................... 50

B.2.2 Acceptance criteria: ..................................................................................... 52

B.3 Core and clamp coating test ................................................................................ 52

B.3.1 Test description ........................................................................................... 52

B.3.2 Acceptance criteria ...................................................................................... 52

B.4 Field test ............................................................................................................. 52

B.4.1 Test description ........................................................................................... 52

B.4.2 Acceptance criteria ...................................................................................... 53

Annex C (normative) Cooling of transformer in naturally ventilated room ............................. 54

C.1 Assumptions ....................................................................................................... 54

C.2 Data for the calculation of ventilation ................................................................... 55

C.3 Output ................................................................................................................ 55

C.4 Numerical application for a 1 000 kVA transformer ............................................... 56

Annex D (normative) Calculation of the losses with different reference temperatures

and/or winding material ....................................................................................................... 57

Bibliography ....................................................................................................................... 60

Figure 1 – Basic measuring circuit for the partial discharge test for a single-phase

transformer ......................................................................................................................... 29

Figure 2 – Basic measuring circuit for the partial discharge test for a three-phase

transformer ......................................................................................................................... 29

Figure 3 – Voltage application for routine partial discharge test ............................................ 30

Figure 4 – Example of back-to-back method – Single phase ................................................ 33

Figure 5 – Example of back-to-back method – Three-phase ................................................. 33

Figure 6 – Voltage application for special partial discharge test ........................................... 35

Figure 7 – Test chamber ..................................................................................................... 41

Figure 8 – Test chamber details .......................................................................................... 42

Figure B.1 – Salt fog multi-parameter ageing cycle .............................................................. 51

Figure C.1 – Heat dissipation in a natural ventilated room .................................................... 54

Table 1 – Letter symbols ..................................................................................................... 15

Table 2 – Winding temperature-rise limits ............................................................................ 18

Table 3 – Test voltage levels ............................................................................................... 19

Table 4 – Applied voltage level correction factor .................................................................. 20

Table 5 – Sequence of tests ................................................................................................ 23

Table 6 – Approximate acceleration level and performance level .......................................... 25

Table 7 – Ground acceleration level (AG) ............................................................................ 26

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SIST EN IEC 60076-11:2019
IEC 60076-11:2018 © IEC 2018 – 5 –

Table 8 – Recommended super elevation factors (K) ........................................................... 26

Table 9 – Direction factors (D) ............................................................................................ 26

Table 10 – Climatic class features ....................................................................................... 35

Table 11 – Environmental classes ....................................................................................... 38

Table 12 – Dimension of the chamber ................................................................................. 40

Table B.1 – Outdoor environmental classes ......................................................................... 50

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SIST EN IEC 60076-11:2019
– 6 – IEC 60076-11:2018 © IEC 2018
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
POWER TRANSFORMERS –
Part 11: Dry-type transformers
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote

international co-operation on all questions concerning standardization in the electrical and electronic fields. To

this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,

Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC

Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested

in the subject dealt with may participate in this preparatory work. International, governmental and non-

governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely

with the International Organization for Standardization (ISO) in accordance with conditions determined by

agreement between the two organizations.

2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

consensus of opinion on the relevant subjects since each technical committee has representation from all

interested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

misinterpretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

transparently to the maximum extent possible in their national and regional publications. Any divergence

between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in

the latter.

5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of

patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60076-11 has been prepared by IEC technical committee 14:

Power transformers.

This second edition cancels and replaces the first edition published in 2004 and constitutes a

technical revision.
The main changes with regard to the previous edition are as follows:
• Extension of the scope up to 72,5kV
• Enclosure management in regards of the performance
• Management of the dielectric and thermal features with altitude
• New climatic classes for a better adaptation of customers’ need
• Establishment of the relation between location and environmental classes

• For fire behaviour classes, limitation at 1 000 kVA and process of test more robust

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SIST EN IEC 60076-11:2019
IEC 60076-11:2018 © IEC 2018 – 7 –
• Introduction of Seismic class
• Recommendations for amorphous transformers
The text of this International Standard is based on the following documents:
FDIS Report on voting
14/964/FDIS 14/972/RVD

Full information on the voting for the approval of this International Standard ca

...

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