EN IEC 60076-22-3:2019

Power transformers - Part 22-3: Power transformer and reactor fittings - Insulating liquid to air heat exchangers

This part of IEC 60076 applies to liquid to air heat exchangers, using forced air and forced liquid circuits, used on liquid immersed power transformers according to IEC 60076-1 and reactors according to IEC 60076-6 with and without conservator for indoor or outdoor installation. It outlines the service conditions and the mechanical and electrical requirements that are common to this equipment. It also outlines the operation requirements specific to this equipment as well as the preferred dimensions relevant for interchangeability and the type and routine tests to be performed.

Leistungstransformatoren und Drosselspulen Anbauten - Teil 22-3: Isolierflüssigkeit-Luft-Wärmetauscher

Transformateurs de puissance - Partie 22-3: Accessoires pour transformateurs de puissance et bobines d’inductance - Aéroréfrigérants

La présente partie de l’IEC 60076 s’applique aux aéroréfrigérants, utilisant des circuits à circulation forcée d’air et de liquide, utilisés sur les transformateurs de puissance immergés (conformes à l’IEC 60076-1) et les bobines d’inductance (conformes à l’IEC 60076-6) avec ou sans conservateur pour les installations intérieures ou extérieures. Elle présente les conditions de service et les exigences mécaniques et électriques communes à cet équipement. Elle présente également les exigences de fonctionnement spécifiques à cet équipement et les dimensions préférentielles pertinentes pour l’interchangeabilité, ainsi que les essais de type et individuels de série à réaliser.

Hladilna oprema za močnostne transformatorje in dušilke – 22-3. del: Toplotni izmenjevalniki izolacijska tekočina-zrak (olje-zrak)

Ta standard se uporablja za zračne izmenjevalnike toplote s potisnim zračnim in tekočinskim krogom, ki se uporabljajo na v tekočini potopljenih močnostnih transformatorjih v skladu s standardom IEC 60076-1 in reaktorje v skladu s standardom IEC 60076-6 z raztezno posodo in brez nje za notranjo ter zunanjo namestitev. V njem so opisani servisni pogoji ter mehanske in električne zahteve, ki so skupne tej opremi. Določa tudi obratovalne zahteve za posamezno opremo in prednostne dimenzije, ki so pomembne za izmenljivost ter rutinske in tipske preskuse, ki jih je treba opraviti.

General Information

• Status: Published
• Publication Date: 18-Apr-2019
• Withdrawal Date: 11-Apr-2022
• ICS: 29.180 - Transformers. Reactors
• Technical Committee: CLC/TC 14 - Power transformers
• Drafting Committee: IEC/TC 14 - IEC_TC_14
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 19-Apr-2019
• Completion Date: 19-Apr-2019
• Ref Project: SIST EN IEC 60076-22-3:2019 - Power transformer and reactor cooling equipment - Part 22-3: Insulating liquid to air heat exchangers

Relations

• Replaces: EN 50216-10:2009 - Power transformer and reactor fittings - Part 10: Oil-to-air heat exchangers
• Effective Date: 16-Mar-2021

Overview

EN IEC 60076-22-3:2019 (CLC) specifies requirements for insulating liquid to air heat exchangers used as cooling equipment for liquid‑immersed power transformers (per IEC 60076-1) and reactors (per IEC 60076-6). It covers units using forced air and forced liquid circuits for indoor or outdoor installation, with or without a conservator. The standard defines service conditions, common mechanical and electrical requirements, operational requirements, preferred dimensions for interchangeability, and the type and routine tests to be performed.

Key Topics and Technical Requirements

• Scope and applicability: Heat exchangers for oil‑filled transformers and reactors, forced air/liquid circuits, indoor/outdoor use.
• Service conditions: Environmental and operating conditions that affect design and performance.
• Mechanical and electrical requirements: Construction, materials, corrosion protection (external and insulating liquid side), degree of protection (IP) for electrical components.
• Insulating liquid characteristics: Requirements and references for insulating fluids in contact with the heat exchanger.
• Design elements: Main components such as headers, tube sheets, tube bundles, turbulators, passes and standard cooling arrangements; preferred dimensions for interchangeability.
• Information and marking: Rating plate data, rated cooling capacity, and details to provide with enquiries and orders.
• Testing requirements: Lists of routine tests (tightness, visual inspection, functional tests, cleanliness, external painting) and type tests (rated values/performance tests).
• Performance & variation: Guidance on cooling capacity variation with oil temperature, air flow and oil flow (informative annexes).
• Annexes: Informative design details (Annex A) and performance data (Annex B) to support selection and verification.

Applications and Who Uses This Standard

EN IEC 60076-22-3:2019 is used by:

• Transformer and reactor manufacturers specifying or designing oil‑to‑air heat exchangers.
• Electrical and mechanical design engineers selecting cooling equipment for substations and industrial installations.
• Test laboratories and quality assurance teams performing routine and type tests.
• Utilities, EPC contractors and procurement/specification writers requiring compliant, interchangeable cooling fittings. Practical uses include specifying cooling unit performance, ensuring material and corrosion protection compatibility with insulating fluids, and defining test protocols and interchangeability dimensions.

Related Standards

Key referenced standards include:

• IEC 60076-1 (Power transformers – General)
• IEC 60076-6 (Reactors)
• IEC 60296 (Insulating oils)
• IEC 60529 (IP Code)
• ISO 3746 / ISO 9614‑2 (acoustic measurement methods)
• ISO 12944 (corrosion protection of steel structures)

Using EN IEC 60076-22-3:2019 ensures consistent, tested, and interoperable insulating liquid to air heat exchangers for safe and reliable transformer and reactor cooling systems.

Standards Content (Sample)

SLOVENSKI STANDARD
01-november-2019
Hladilna oprema za močnostne transformatorje in dušilke – 22-3. del: Toplotni
izmenjevalniki izolacijska tekočina-zrak (olje-zrak)
Power transformer and reactor cooling equipment - Part 22-3: Insulating liquid to air heat
exchangers
Ta slovenski standard je istoveten z: EN IEC 60076-22-3:2019
ICS:
29.180 Transformatorji. Dušilke Transformers. Reactors
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 60076-22-3

NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2019
ICS 29.180
English Version
Power transformers - Part 22-3: Power transformer and reactor
fittings - Insulating liquid to air heat exchangers
(IEC 60076-22-3:2019)
Transformateurs de puissance - Partie 22-3: Accessoires Leistungstransformatoren und Drosselspulen
pour transformateurs de puissance et bobines d'inductance Kühlungseinrichtung - Teil 22-3: Isolierte Flüssigkeit-Luft-
- Aéroréfrigérants Wärmetauscher
(IEC 60076-22-3:2019) (IEC 60076-22-3:2019)
This European Standard was approved by CENELEC on 2019-04-12. 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
© 2019 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60076-22-3:2019 E

European foreword
The text of document 14/995/FDIS, future edition 1 of IEC 60076-22-3, prepared by IEC/TC 14 "Power
transformers" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2020-01-12
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2022-04-12
document have to be withdrawn
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 60076-22-3:2019 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 60076-6 NOTE Harmonized as EN 60076-6
ISO 3506-1 NOTE Harmonized as EN ISO 3506-1
ISO 9001 NOTE Harmonized as EN ISO 9001

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 60076-1 -  Power transformers - Part 1: General EN 60076-1 -
IEC 60076-7 -  Power transformers - Part 7: Loading guide for oil- - -
immersed power transformers
IEC 60296 -  Fluids for electrotechnical applications - Unused - -
mineral insulating oils for transformers and
switchgear
IEC 60529 -  Degrees of protection provided by enclosures (IP - -
Code)
ISO 3746 -  Acoustics - Determination of sound power levels EN ISO 3746 -
and sound energy levels of noise sources using
sound pressure - Survey method using an
enveloping measurement surface over a reflecting
plane
ISO 4406 -  Hydraulic fluid power - Fluids - Method for coding - -
the level of contamination by solid particles
ISO 7005 series Pipe flanges - series
ISO 9614-2 -  Acoustics - Determination of sound power levels EN ISO 9614-2 -
of noise sources using sound intensity - Part 2:
Measurement by scanning
ISO 12944 series Paints and varnishes - Corrosion protection of EN ISO 12944 series
steel structures by protective paint systems

IEC 60076-22-3 ®
Edition 1.0 2019-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Power transformers –
Part 22-3: Power transformer and reactor fittings – Insulating liquid to air heat

exchangers
Transformateurs de puissance –

Partie 22-3: Accessoires pour transformateurs de puissance et bobines

d’inductance – Aéroréfrigérants

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.180 ISBN 978-2-8322-6634-2

– 2 – IEC 60076-22-3:2019 © IEC 2019
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 General requirements . 8
4.1 Service conditions . 8
4.2 Degree of protection of electrical components (IP) . 8
4.3 Corrosion protection . 8
4.3.1 External (atmosphere) . 8
4.3.2 Insulating liquid side . 8
4.4 Insulating liquid characteristics . 8
5 Design and characteristics . 9
5.1 Main components and characteristics . 9
5.1.1 Headers . 9
5.1.2 Tube sheets . 9
5.1.3 Tube bundle . 9
5.1.4 Turbulators . 9
5.1.5 Passes . 9
5.1.6 Standard design and cooling arrangement . 9
5.2 General characteristics . 9
5.2.1 Rating plate information . 9
5.2.2 Rated cooling capacity . 10
5.2.3 Information to be provided with enquiry and order. 10
5.2.4 Mechanical design . 11
5.2.5 Preparation for transport and storage . 12
6 Tests . 13
6.1 General requirements for tests . 13
6.1.1 General . 13
6.1.2 List of tests . 13
6.2 Routine tests. 13
6.2.1 Tightness tests . 13
6.2.2 Visual inspection . 14
6.2.3 Functional test . 14
6.2.4 Cleanliness . 14
6.2.5 External painting . 14
6.3 Type tests – Rated values test . 14
Annex A (informative) Design details of heat exchangers . 15
A.1 Dimensions and designs . 15
A.1.1 General . 15
A.1.2 Schematic design of cooling unit (without oil pump) . 15
A.1.3 Versions of flange arrangement . 16
A.2 Constructional materials – Common selection of materials . 17
Annex B (informative) Performance of heat exchangers . 18
B.1 General . 18
B.2 Performance of heat exchangers. 18

IEC 60076-22-3:2019 © IEC 2019 – 3 –
B.3 Variation of cooling capacity as function of average oil temperature rise . 19
B.4 Variation of cooling capacity for modified flow quantities . 20
B.4.1 Variation of cooling capacity as function of air flow quantity . 20
B.4.2 Variation of cooling capacity as function of oil flow quantity . 21
Bibliography . 22

Figure A.1 – Schematic design of cooling unit (without oil pump) . 15
Figure A.2 – Versions of flange arrangement . 16
Figure B.1 – General diagram for cooling temperatures . 18
Figure B.2 – Variation of cooling capacity as function of average oil temperature rise . 19
Figure B.3 – Variation of cooling capacity as function of air flow quantity . 20
Figure B.4 – Variation of cooling capacity as function of oil flow quantity . 21

Table 1 – Mandatory fittings . 12

– 4 – IEC 60076-22-3:2019 © IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
POWER TRANSFORMERS –
Part 22-3: Power transformer and reactor fittings –
Insulating liquid to air heat exchangers

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,
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preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
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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 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
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
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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
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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 60076-22-3 has been prepared by IEC technical committee 14:
Power transformers.
The text of this International Standard is based on the following documents:
FDIS Report on voting
14/995/FDIS 14/1003/RVD
Full information on the voting for the approval of this International Standard can be found in the
report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60076 series, published under the general title Power transformers,
can be found on the IEC website.

IEC 60076-22-3:2019 © IEC 2019 – 5 –
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 60076-22-3:2019 © IEC 2019
INTRODUCTION
Under the part title “Power transformer and reactor fittings”, this part of IEC 60076-22 covers
the insulating liquid to air heat exchangers in the cooling circuits of power transformers and
reactors.
IEC 60076-22-3:2019 © IEC 2019 – 7 –
POWER TRANSFORMERS –
Part 22-3: Power transformer and reactor fittings –
Insulating liquid to air heat exchangers

1 Scope
This part of IEC 60076 applies to liquid to air heat exchangers, using forced air and forced liquid
circuits, used on liquid immersed power transformers according to IEC 60076-1 and reactors
according to IEC 60076-6 with and without conservator for indoor or outdoor installation. It
outlines the service conditions and the mechanical and electrical requirements that are common
to this equipment.
It also outlines the operation requirements specific to this equipment as well as the preferred
dimensions relevant for interchangeability and the type and routine tests to be performed.
2 Normative references
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.
IEC 60076-1, Power transformers – Part 1: General
IEC 60076-7, Power transformers – Part 7: Loading guide for mineral oil-immersed power
transformers
IEC 60296, Fluids for electrotechnical applications – Unused mineral insulating oils for
transformers and switchgear
IEC 60529, Degrees of protection provided by enclosures (IP Code)
ISO 3746, Acoustics – Determination of sound power levels and sound energy levels of noise
sources using sound pressure – Survey method using an enveloping measurement surface over
a reflecting plane
ISO 4406, Hydraulic fluid power – Fluids – Method for coding the level of contamination by solid
particles
ISO 7005 (all parts), Pipe flanges
ISO 9614-2, Acoustics – Determination of sound power levels of noise sources using sound
intensity – Part 2: Measurement by scanning
ISO 12944 (all parts), Paints and varnishes – Corrosion protection of steel structures by
protective paint systems
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

– 8 – IEC 60076-22-3:2019 © IEC 2019
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3.1
insulating liquid to air heat exchanger
component for the cooling of the insulating liquid of the transformer, using forced circulation of
the insulating liquid and a forced air flow
4 General requirements
4.1 Service conditions
The normal service conditions set out in IEC 60
...