IEC TR 63259:2022
(Main)Water cooling systems for power electronics used in electrical transmission and distribution systems
Water cooling systems for power electronics used in electrical transmission and distribution systems
IEC TR 63259:2022(E) provides guidelines for the application of water cooling systems for power electronics used in electrical transmission and distribution systems.
This document describes a kind of water cooling system, in which de-ionized water or de-ionized water mixed with other solutes is used as the heat transfer agent for the removal of heat from power electronic equipment. Water cooling system can be separated into main circuit, and control and protection system. Other cooling systems, in which de-ionized water is not the heat transfer agent, are excluded in this document.
This document provides guidance and supporting information for both purchaser(s) and potential supplier(s). It can be used as the basis for drafting a procurement specification and as a guide during project implementation.
General Information
Standards Content (Sample)
IEC TR 63259
®
Edition 1.0 2022-03
TECHNICAL
REPORT
Water cooling systems for power electronics used in electrical transmission and
distribution systems
IEC TR 63259:2022-03(en)
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IEC TR 63259
®
Edition 1.0 2022-03
TECHNICAL
REPORT
Water cooling systems for power electronics used in electrical transmission
and distribution systems
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.240.99 ISBN 978-2-8322-1090-5
Warning! Make sure that you obtained this publication from an authorized distributor.
® Registered trademark of the International Electrotechnical Commission
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– 2 – IEC TR 63259:2022 © IEC 2022
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Service conditions . 8
4.1 General . 8
4.2 Indoor conditions . 9
4.3 Outdoor conditions . 9
4.4 Electrical supply conditions . 9
5 Technical performance . 9
5.1 System functions . 9
5.2 Main circuit . 11
5.2.1 Design input parameters . 11
5.2.2 Components . 12
5.3 Heat exchanger . 14
5.3.1 General . 14
5.3.2 Air cooler . 14
5.3.3 Evaporative cooling tower . 15
5.3.4 Liquid-to-liquid heat exchanger . 16
5.3.5 Chiller unit . 17
5.4 Control and protection system . 17
5.4.1 General . 17
5.4.2 Control . 18
5.4.3 Protection . 18
5.4.4 Monitoring and recording . 19
5.5 Freezing prevention . 19
5.6 Rating plate . 19
6 Documentation . 19
7 Tests . 20
7.1 Summary of tests . 20
7.2 Description of tests . 20
7.2.1 Visual inspection . 20
7.2.2 Insulation test . 21
7.2.3 Pressure and leakage test . 21
7.2.4 Hydraulic performance test . 21
7.2.5 Thermal performance test . 21
7.2.6 Control and protection test . 21
7.2.7 EMC test . 21
7.2.8 Operation test . 21
7.2.9 Inspection of internal cleanliness . 21
7.2.10 Pump and motor alignment check . 22
7.2.11 Coolant freezing point check . 22
7.2.12 Vibration check . 22
7.2.13 Audible noise check . 22
7.2.14 Current check . 22
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IEC TR 63259:2022 © IEC 2022 – 3 –
7.2.15 Communication and interface test . 22
8 Maintenance . 22
9 Safety . 22
10 Environmental impact . 22
Bibliography . 24
Figure 1 – Typical flow chart of water cooling system application . 11
Figure 2 – Typical flow chart of air cooler application . 15
Figure 3 – Typical flow chart of evaporative cooling tower application . 16
Figure 4 – Typical flow chart of water-to-water heat exchanger application . 16
Figure 5 – Typical flow chart of chiller unit application . 17
Table 1 – Typical design input parameters of water cooling system . 12
Table 2 – List of tests . 20
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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
WATER COOLING SYSTEMS FOR POWER ELECTRONICS USED
IN ELECTRICAL TRANSMISSION AND DISTRIBUTION SYSTEMS
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
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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.
IEC TR 63259 has been prepared by subcommittee 22F: Power electronics for electrical
transmission and distribution systems, of IEC technical committee 22: Power electronic systems
and equipment. It is a Technical Report.
The text of this Technical Report is based on the following documents:
Draft Report on voting
22F/650/DTR 22F/668/RVDTR
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Report is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
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IEC TR 63259:2022 © IEC 2022 – 5 –
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under 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
In the power transmission and distribution systems, power electronic equipment, such as LCC-
HVDC (line commutated converter high voltage direct current) converter valve, VSC-HVDC
(voltage sourced converter high voltage direct current) converter valve, SVC (static var
compensator), STATCOM (static synchronous compensator) and power distribution cabinets,
are mainly used for the conversion and control of current. Heat emitted from power electronics,
like thyristors, IGBTs or other kinds, needs to be removed continuously. Water cooling system
is commonly used as an efficient way to remove the heat from power electronic equipment,
especially when operation voltage of equipment reaches 1 000 V or above. To meet the
insulation requirement, water needs to be deionized to have the property of least conductivity.
De-ionized water can be mixed with antifreeze or other solutes to achieve lower freezing point
or obtain other characteristics.
As one of the most important auxiliary parts of power transmission and distribution systems, a
great deal of research and practices have been made in many countries and relevant national
standards or enterprise standards have been established. This document collects experience
of design, manufacturing, and testing in different fields and provides a guideline for further
application. However, the supplier is not necessarily required to provide all functions that are
included/described in this document, unless clearly specified/required by the purchaser.
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IEC TR 63259:2022 © IEC 2022 – 7 –
WATER COOLING SYSTEMS FOR POWER ELECTRONICS USED
IN ELECTRICAL TRANSMISSION AND DISTRIBUTION SYSTEMS
1 Scope
This document provides guidelines for the application of water cooling systems for power
electronics used in electrical transmission and distribution systems.
This document describes a kind of water cooling system, in which de-ionized water or de-ionized
water mixed with other solutes is used as the heat transfer agent for the removal of heat from
power electronic equipment. Water cooling system can be separated into main circuit, and
control and protection system. Other cooling systems, in which de-ionized water is not the heat
transfer agent, are excluded in this document.
This document provides guidance and supporting information for both purchaser(s) and
potential supplier(s). It can be used as the basis for drafting a procurement specification and
as a guide during project implementation.
NOTE Usually, the agreement between the purchaser and the supplier of the water cooling system includes specific
requirements regarding contractual requirements of particular delivery. Such specific requirements will supersede
the general/typical description mentioned in this document, and all functions mentioned in this document are not
necessarily applicable/delivered for all systems.
2 Normative references
There are no normative references in this document.
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
3.1
cooling medium
liquid (for example water) and/or gas (for example air) which removes the heat that is generated
by the equipment, from the heat exchanger
Note 1 to entry: A cooling medium is only used in the heat exchanger(s).
[SOURCE: IEC 60146-1-1:2009, 3.8.1, modified – The words "or gas" have been replaced by
"and/or gas", the words "from the equipment" have been replaced by "that is generated by the
equipment, from the heat exchanger", and the note to entry has been added.]
3.2
heat transfer agent
coolant within the equipment to transfer the heat from its source to a heat exchanger from where
the heat is removed by the cooling medium
Note 1 to entry: In the context of this Technical Report, only de-ionized water and de-ionized water mixed with other
solutes are considered as heat transfer agents.
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[SOURCE: IEC 60146-1-1:2009, 3.8.2, modified – The words "liquid (for example water) or gas
(for example air)" have been replaced by "coolant", and the note to entry has been added.]
3.3
de-ionized water
purified water from which ionic species have been partially or completely removed, particularly
by the use of ion-exchanger resins to achieve the least conductivity
3.4
main circuit
cooling circuit that exchanges heat with power electronic equipment (or with heat sink attached)
by heat transfer agent
Note 1 to entry: Heat sink attached to power electronic equipment for heat transfer is considered as an integral
part of power electronic equipment.
3.5
rated cooling capacity
cooling capacity of water cooling system at specified design conditions to cool the power
electronic equipment
Note 1 to entry: Cooling capacity can be higher than the power dissipation of the equipment being cooled to cover
pump losses, chiller losses, etc.
3.6
rated flow
specified flow through power electronic equipment at rated cooling capacity
Note 1 to entry: Flow from pump(s) can be higher than the flow through the equipment being cooled to cover flow
into water treatment circuit, etc.
3.7
secondary circuit
cooling circuit that exchanges heat from the main circuit into a cooling medium in the liquid form
and from there transports it to a further heat exchanger from where it is rejected to ambient
Note 1 to entry: Not all cooling systems use secondary circuit.
4 Service conditions
4.1 General
Service conditions can be divided into indoor conditions, outdoor conditions, and electrical
supply conditions. All these conditions need to be subject to the specific requirement of
purchasers or site location.
For indoor conditions, the specific requirement of indoor equipment, like pump motors and
cabinets, needs to be included. The indoor conditions can be achieved by appropriate HVAC
(heating ventilation and air-conditioning) system. The outdoor conditions and power conditions
mostly depend on the site condition.
Some conditions, like altitude and seismic intensity, apply to all parts. Other environmental
conditions, like corrosion, can differ when applied to indoor and outdoor equipment.
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IEC TR 63259:2022 © IEC 2022 – 9 –
4.2 Indoor conditions
The following conditions need to be considered for indoor equipment:
a) the indoor temperature and humidity, which need to follow project requirements whilst
complying with IEC 60654-1;
NOTE Local regulations can also exist.
b) condensation, which needs to be avoided for both mechanical equipment and control
equipment;
c) explosive mixtures of dust or gases, corrosive gas or steam;
d) unusual mechanical stresses, for example shocks and vibrations;
e) exposure to strong electromagnetic interference.
4.3 Outdoor conditions
For outdoor equipment exposed to the environment, some conditions as follows need to be
carefully considered:
a) corrosivity level at site, which is vital for life of steel structure and equipment structure,
refers to ISO 12944-2, or needs to be subject to purchaser’s requirement;
b) availability of raw water, which needs to be considered when evaporative cooling tower is
included as heat exchanger;
c) special location, such as residential area or natural park, where operation noise of outdoor
equipment is subject to local laws;
d) salty air (for example proximity to the sea), high humidity, dripping water or corrosive gases.
4.4 Electrical supply conditions
Voltage and frequency fluctuations of power supply and control power supply need to meet the
requirement according to IEC 60038, or as specified by the purchaser. AC power for pumps,
fans, etc. and control power for auxiliary equipment need to be configured separately.
Redundancy of power supply (both AC and DC) as well as power quality of power supply
(voltage fluctuations, frequency fluctuations, three-phase voltage unbalance, etc.) need to be
considered and applied where feasible.
5 Technical performance
5.1 System functions
The main circuit is a continuous circulating loop filled with heat transfer agent. If required by
the power electronic equipment, oxygen is prevented from entering the system. The design
prevents dirt from entering the system as well. Figure 1 presents an example of typical flow
chart of water cooling system application.
Circulation pump(s), heat exchanger, strainer, fine filter, expansion vessel(s), and de-ionization
equipment need to be included. Refill equipment, electrical heater, and by-pass branch are
optional but can be included as per power electronic equipment’s or purchaser’s requirement.
Pressure meter and transducer, temperature transducer, conductivity transducer, flow
transducer, and level meter and transducer need to be included in the loop to monitor the
performance of the system. Oxygen meter, pH meter, or other kinds of meters and/or
transducers are optional or can be installed as per requirement of purchaser and/or when
specified.
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– Main circuit
Main circuit directly exchanges heat with power electronic equipment, and transfers the heat
which is emitted from the power electronic equipment, to heat exchanger. Indoor equipment
can be mounted on frames, which is convenient for the testing and installation at site. The
main circuit needs to be designed to meet the required pressure, flow, temperature,
conductivity, and other requirements for power electronic equipment.
– Heat exchanger
Within heat exchanger, cooling medium (air or raw water at site) exchanges heat with heat
transfer agent, which is heated in the power electronic equipment, and transfers the heat to
atmosphere or other reliable sources to take over the heat energy from the system. The
cooled heat transfer agent will flow back to be heated in power electronic equipment, then
will be cooled again in the heat exchanger. The heat exchanger needs to have the cooling
capacity no less than that required by power electronic equipment at the most severe
performance condition.
– Control and protection system
Control and protection system needs to comprise following basic functions: protection of
power electronic equipment related to water cooling system, and control, and monitoring
and recording. The transducers which serve the protection system can be duplicated or
triplicated as per the requirement of purchaser(s).
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IEC TR 63259:2022 © IEC 2022 – 11 –
NOTE Symbols of the flow chart are designed according to ISO 3511-1, ISO 3511-2, ISO 14617-1, ISO 14617-3,
ISO 14617-7, ISO 14617-8, ISO 14617-9, ISO 14617-11, and ISO 14617-12.
Figure 1 – Typical flow chart of water cooling system application
5.2 Main circuit
5.2.1 Design input parameters
Typical design input parameters of main circuit are listed in Table 1.
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Table 1 – Typical design input parameters of water cooling system
Parameter of water cooling system Unit Description
Rated cooling capacity kW Refer to 3.5
Design inlet temperature of power Inlet temperature to power electronic equipment at design
°C
electronic equipment conditions
Maximum inlet temperature of power °C Used for the protection of power electronics
electronic equipment
Minimum inlet temperature of power °C Used for the protection of power electronics
electronic equipment
Rated flow of power electronic l/min Refer to 3.6
equipment
Maximum design inlet pressure of power kPa Maximum allowed working pressure of power electronic
electronic equipment equipment
Power electronic equipment pressure kPa Design pressure drop of power electronic equipment at
drop rated flow
Maximum conductivity of main circuit µS/cm Maximum conductivity required by power electronic
equipment
Maximum and minimum environmental °C Maximum and minimum value of dry-bulb temperature or
temperature wet-bulb temperature of outdoor environment
Type and amount of antifreeze or other % Water solute required by project or purchaser(s)
solutes in coolant (if any)
5.2.2 Components
5.2.2.1 Circulation pump
Circulation pump(s) needs to be provided to circulate heat transfer agent inside piping.
Redundant pump(s), if required, needs to be installed in parallel with pump(s) in operation. The
pump(s) in operation needs to be able to provide the required flow.
5.2.2.2 Filter
– Strainer
Strainer needs to be included in the main circuit to filter solid particles and prevent them
entering the pipe of power electronic equipment. The mesh size needs typically to be no
larger than 250 μm, or less if required by the purchaser’s requirements. Filter element inside
can be either cleaned or changed when it is polluted.
– Fine filter
Fine filter(s) needs to be included in the water treatment circuit to ensure that no deionizer
resin and/or any other particles enter the main circuit. Mesh size of fine filter needs to be
no larger than typical 25 μm or be subject to purchaser’s requirement. Filter element inside
can be either cleaned or changed when it is polluted.
5.2.2.3 De-ionizing equipment
To ensure the conductivity of heat transfer agent remains within an acceptable limit of the power
electronic equipment, de-ionizing equipment needs to be included to remove ions continuously.
A mixture of uniform granular particle sized polystyrene cation and anion resins needs to be
used.
5.2.2.4 Refill equipment
Refill equipment can be included to replenish coolant in main circuit. The coolant needs to be
filtered and preferably deionized before entering the main circuit. Refill pump(s) needs to be
included as the major component. The working pressure of system and pressure loss through
refill circuit need to be considered in the design of refill pump. The refill arrangement can be
automatic or manual.
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IEC TR 63259:2022 © IEC 2022 – 13 –
5.2.2.5 Expansion vessel
Expansion vessel(s) needs to be included to wit
...
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