SIST EN IEC 60076-22-4:2019

Power transformer and reactor cooling equipment - Part 22-4: Insulating liquid to water heat exchangers

This standard applies to liquid to water heat exchangers, using forced water 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 22-4: Isolierflüssigkeit-Wasser-Wärmetauscher

Transformateurs de puissance - Partie 22-4: Accessoires pour transformateurs de puissance et bobines d’inductance – Hydroréfrigérants

La présente partie de l’IEC 60076-22 s’applique aux hydroréfrigérants, utilisant des circuits à circulation forcée d’eau et de liquide, utilisés sur des transformateurs de puissance immergés dans un liquide (conformes à l’IEC 60076-1) et des 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 essasi de type et individuels de série à réaliser.

Hladilna oprema za močnostne transformatorje in dušilke – 22-4. del: Toplotni izmenjevalniki izolacijska tekočina-voda (olje-voda)

Ta standard se uporablja za vodne izmenjevalnike toplote s potisnim vodnim 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: 29-Sep-2019
• ICS: 29.180 - Transformers. Reactors
• Technical Committee: ETR - Power transformers
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 25-Jul-2019
• Due Date: 29-Sep-2019
• Completion Date: 30-Sep-2019
• Ref Project: EN IEC 60076-22-4:2019 - Power transformers - Part 22-4: Power transformer and reactor fittings - Insulating liquid to water heat exchangers

Relations

• Replaces: SIST EN 50216-9:2009 - Power transformer and reactor fittings - Part 9: Oil-to-water heat exchanger
• Effective Date: 16-Mar-2021

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN IEC 60076-22-4:2019
01-november-2019
Hladilna oprema za močnostne transformatorje in dušilke – 22-4. del: Toplotni
izmenjevalniki izolacijska tekočina-voda (olje-voda)
Power transformer and reactor cooling equipment - Part 22-4: Insulating liquid to water
heat exchangers
Ta slovenski standard je istoveten z: EN IEC 60076-22-4:2019
ICS:
29.180 Transformatorji. Dušilke Transformers. Reactors
SIST EN IEC 60076-22-4:2019 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN IEC 60076-22-4:2019


EUROPEAN STANDARD EN IEC 60076-22-4

NORME EUROPÉENNE

EUROPÄISCHE NORM
April 2019
ICS 29.180

English Version
Power transformers - Part 22-4: Power transformer and reactor
fittings - Insulating liquid to water heat exchangers
(IEC 60076-22-4:2019)
Transformateurs de puissance - Partie 22-4: Accessoires Leistungstransformatoren und Drosselspulen
pour transformateurs de puissance et bobines d'inductance Kühlungseinrichtung - Teil 22-4: Isolierte Flüssigkeit-
- Hydroréfrigérants Wasser-Wärmetauscher
(IEC 60076-22-4:2019) (IEC 60076-22-4:2019)
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 60076-22-4:2019 E

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SIST EN IEC 60076-22-4:2019
EN IEC 60076-22-4:2019 (E)
European foreword
The text of document 14/996/FDIS, future edition 1 of IEC 60076-22-4, prepared by IEC/TC 14 "Power
transformers" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
EN IEC 60076-22-4:2019.
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 60076-22-4:2019 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

2

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SIST EN IEC 60076-22-4:2019
EN IEC 60076-22-4:2019 (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 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 - EN 60296 -
Unused mineral insulating oils for
transformers and switchgear
IEC 60529 -  Degrees of protection provided by enclosures - -
(IP Code)
ISO 4406 -  Hydraulic fluid power - Fluids - Method for - -
coding the level of contamination by solid
particles
ISO 12944 series Paints and varnishes - Corrosion protection of EN ISO 12944 series
steel structures by protective paint systems

3

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SIST EN IEC 60076-22-4:2019



IEC 60076-22-4

®


Edition 1.0 2019-03




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE











Power transformers –

Part 22-4: Power transformer and reactor fittings – Insulating liquid to water

heat exchangers




Transformateurs de puissance –

Partie 22-4: Accessoires pour transformateurs de puissance et bobines


d’inductance – Hydroréfrigérants













INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE


INTERNATIONALE




ICS 29.180 ISBN 978-2-8322-6635-9




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 60076-22-4:2019
– 2 – IEC 60076-22-4:2019 © 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 Performance requirements . 8
4.3 Degree of protection of electrical components (IP) . 8
4.4 Corrosion protection . 8
4.4.1 External (atmosphere) . 8
4.4.2 Insulating liquid side . 9
4.4.3 Water side . 9
4.5 Insulating liquid characteristics . 9
5 Design and characteristics . 9
5.1 General . 9
5.2 Main components and characteristics . 9
5.2.1 General . 9
5.2.2 Shell . 9
5.2.3 Tube bundle in double tube arrangement . 9
5.2.4 Headers . 10
5.3 General characteristics . 10
5.3.1 Rating plate information . 10
5.3.2 Information to be provided with enquiry and order. 10
5.3.3 Rated cooling capacity . 11
5.3.4 Mechanical design . 11
5.3.5 Preparation for transport and storage . 13
5.3.6 Mounting and operating conditions . 14
6 Tests . 14
6.1 General requirements for tests . 14
6.1.1 General . 14
6.1.2 List of tests . 14
6.2 Routine tests. 15
6.2.1 Tightness test insulating liquid side . 15
6.2.2 Tightness test water side . 15
6.2.3 Visual inspection . 15
6.2.4 Cleanliness . 15
6.3 Type tests – Rated values test . 15
Annex A (informative) Details of the heat exchangers . 16
A.1 Masses and dimensions . 16
A.2 Collection and forms of suspensory types . 16
A.3 Collection and forms of horizontal types . 17
A.4 Collection and forms of vertical standing types. 18
A.5 Parts list – Materials – Common selection of materials . 19
A.6 Example for fresh water . 20

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Annex B (informative) Rating conditions of the heat exchangers . 21
B.1 General . 21
B.2 Definitions, symbols . 21
B.3 Calculation of capacity in service . 21
B.3.1 Service capacity for different temperatures at inlet according to Figure
B.1 . 21
B.3.2 Service capacity for different mass flows according to Figure B.2 for
plain tubes and according to Figure B.3 for finned tubes . 21
B.3.3 Service capacity for different mass flows and different temperatures . 22
B.3.4 Example for calculation of 25 % capacity margin of new heat
exchangers . 22
Annex C (informative) Example for calculation of capacity in service . 26
Bibliography . 28

Figure A.1 – Collection and forms of suspensory types . 16
Figure A.2 – Collection and forms of horizontal types . 17
Figure A.3 – Collection and forms of vertical standing types . 18
Figure B.1 – Capacity factor depending on inlet temperatures of oil and water . 23
Figure B.2 – Capacity factor depending on mass for plain tubes . 24
Figure B.3 – Capacity factor depending on mass for finned tubes . 25

Table 1 – Water quality data . 12
Table 2 – Mandatory fittings . 13
Table A.1 – Examples of material selection depending on water quality . 20
Table A.2 – Average values for chemically neutral water (fresh water) . 20

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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

POWER TRANSFORMERS –

Part 22-4: Power transformer and reactor fittings –
Insulating liquid to water 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,
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 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 60076-22-4 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
14/996/FDIS 14/1004/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.

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SIST EN IEC 60076-22-4:2019
IEC 60076-22-4:2019 © 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.

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INTRODUCTION
Under the part title “Power transformer and reactor fittings” this part of IEC 60076-22 covers
the insulating liquid to water heat exchangers in the cooling circuits of power transformers and
reactors.
Annex B gives guidance to the end user for approximation of the behaviour of the heat
exchanger under different operation conditions. Annex C gives an example based on the
calculation rules stipulated in Annex B.

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IEC 60076-22-4:2019 © IEC 2019 – 7 –

POWER TRANSFORMERS –

Part 22-4: Power transformer and reactor fittings –
Insulating liquid to water heat exchangers



1 Scope
This part of IEC 60076 applies to liquid to water heat exchangers, using forced water 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 4406, Hydraulic fluid power – Fluids – Method for coding the level of contamination by solid
particles
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.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp

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3.1
insulating liquid to water heat exchanger
component for the cooling of the insulating liquid of the transformer, using forced circulation of
the insulating liquid and forced circulation of water
4 General requirements
4.1 Service conditions
The normal service conditions set out in IEC 60076-1 represent the normal scope of operation
of the device and equipment specified in this document. Unless otherwise specified, fresh water
as defined by Table A.2 shall be considered as cooling water.
Device and equipment specification for operation under service conditions different from the
ones specified by IEC 60076-1 shall be subject to agreement between the purchaser and
supplier, as they require special consideration in the design of the device and equipment.
Any particular condition, which can influence the correct functioning of the cooler, shall be
specified, such as water quality, addition of anti-freeze compounds, mud, microorganisms,
addition of biocides, sea weed, and intermittent operation.
4.2 Performance requirements
Liquid to water heat exchangers should fulfil the following requirements:
• mechanical separation of liquid and water circuit shall be ensured at any time;
• independent design and control of liquid and water conditions shall be possible;
• the access to the water side surfaces shall be possible without influencing or opening the
liquid side circuit;
• easy access to the water side surfaces for inspection and cleaning on site by mechanical
means, for example using brushes;
• the heat exchanger construction shall be suitable for operating conditions complying with
the permissible pressure values of the liquid side and the water side;
• easy detection of possible leakages at the liquid and the water side.
4.3 Degree of protection of electrical components (IP)
The degree of protection of the connecting box or terminal box for an outdoor installation shall
be at least IP 54 according to IEC 60529, unless otherwise specified by the purchaser.
4.4 Corrosion protection
4.4.1 External (atmosphere)
The materials used for the construction of the equipment or the surface treatment shall be
resistant to accidental contact with the insulating liquid and suitable to withstand the
environmental conditions given in 4.1. The corrosion protection shall be agreed between
purchaser and manufacturer according to ISO 12944 (all parts). The responsibility to specify
the correct level of corrosion protection lies with the purchaser and is dependent on the
environment where the transformer will be located and on the durability required. Unless
otherwise specified, minimum withstand level shall be C4 medium durability according to
ISO 12944-6.

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IEC 60076-22-4:2019 © IEC 2019 – 9 –
4.4.2 Insulating liquid side
In consideration of the storage conditions and expected time between shipment and
commissioning, the corrosion protection on the insulating liquid side of the cooling system shall
be agreed between purchaser and manufacturer. As a minimum requirement, precautions shall
be taken to prevent the ingress of moisture and the development of internal corrosion. The
internal flushing with insulation liquid fully miscible and compatible with the liquid to be used in
service conditions and the use of blanking plates with gaskets are considered as a minimum.
Internal painting, nitrogen filling, dehydrating material, etc., can be used as other or additional
solutions.
4.4.3 Water side
The corrosion protection on the water side of the cooling system shall be agreed between
purchaser and manufacturer and is dependent on the water quality. To attain the requested
degree of protection the manufacturer shall choose the combination of material and surface
protection. As a minimum requirement for paint, an epoxy coating with a thickness of 150 µm
shall be applied.
4.5 Insulating liquid characteristics
If not otherwise specified, the insulating liquid is mineral oil according to IEC 60296 and the
operating temperature shall be in accordance with IEC 60076-7.
When the insulating liquid is not mineral oil then the viscosity variation, the operating
temperature and all the other operating characteristics shall be indicated by the purchaser.
5 Design and characteristics
5.1 General
Shell and tube heat exchangers with double tube arrangement are established as the current
best practice of transformer insulating liquid cooling in compliance with all the requirements.
Any different type may be accepted and applied if all the requirements of 4.2 are fulfilled.
5.2 Main components and characteristics
5.2.1 General
See Figure A.1, Figure A.2 and Figure A.3 for reference.
The main components of a shell and tube heat exchanger are the shell, the tube bundle inside
the shell and two headers at both ends of the shell.
5.2.2 Shell
The shell is the cylindrical compartment containing the tube bundle and is provided with flanged
nozzles for piping connection of the insulating liquid. The shell contains the insulating liquid.
Baffles on the tube bundle are used to optimize the liquid path inside the shell.
5.2.3 Tube bundle in double tube arrangement
Double tubes are used for the tube bundle for safety reasons of the transformer. The liquid
pressure outside the tubes is independent from the water pressure and is usually less than the
water pressure inside the tubes.

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• The double tubes consist of two concentric tubes without a blocking fluid in between; the
tubes are straight and the outer tubes are plain or finned. Between the inner and outer tube
there shall be grooves, which enable the detection of a potential leakage by using a proper
device. The double tubes are connected at both ends to the respective tube sheets by roll
expansion or welding. The connection shall be fluid tight.
• The tube bundle can be arranged in different even number of passes to optimize water flow.
Removable tube bundles are the preferred solution for maintenance purposes.
5.2.4 Headers
• Two headers close the shell at both ends.
• One header includes flanged nozzles for the connection to the water piping. Inside the other
header, the water is redirected.
5.3 General characteristics
5.3.1 Rating plate information
The rating plate shall be corrosion resistant and acid proof. It shall be visible when the heat
exchanger is assembled to the transformer and carry the following data:
• logo or name of manufacturer;
• country and manufacturing location;
• number of this document;
• manufacturer identification;
• manufacturer serial number;
• year of manufacturing.
Rated data:
• rated cooling capacity [kW];
3
• rated liquid and water flow quantity [m /h];
• inlet and outlet temperatures liquid-side and water-side [°C];
• pressure drop in the heat exchanger liquid side/water side [bar];
• maximum pressure in service for liquid-side [kPa];
• maximum pressure in service for water-side [kPa];
• maximum design temperature for liquid-side [°C];
• mass of heat exchanger without oil and water [kg];
3
• oil and water quantity for filling [dm ].
5.3.2 Information to be provided with enquiry and order
The purchaser shall supply to the manufacturer the following information with the enquiry:
• insulation liquid characteristics;
• water quality;
• rated cooling capacity Q kW;

r
• water temperature at inlet t ’ °C;
1
• water temperature at outlet (max.) t ’’ °C;
1
• maximu
...