IEC 63075:2019

IEC 63075 ®
Edition 1.0 2019-02
INTERNATIONAL
STANDARD
colour
inside
Superconducting ac power cables and their accessories for rated voltages
from 6 kV to 500 kV – Test methods and requirements
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IEC 63075 ®
Edition 1.0 2019-02
INTERNATIONAL
STANDARD
colour
inside
Superconducting ac power cables and their accessories for rated voltages

from 6 kV to 500 kV – Test methods and requirements

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.060.20 ISBN 978-2-8322-6522-2

– 2 – IEC 63075:2019  IEC 2019
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 10
3.1 Definitions of dimensional values (thicknesses, cross-sections, etc.) . 10
3.2 Definitions concerning tests . 10
3.3 Other definitions (general design and cryogenic system) . 11
4 Voltage and current designations . 13
4.1 Rated voltages . 13
4.2 Rated operating current . 13
5 Cable materials . 14
5.1 Cable conductor materials . 14
5.2 Cable insulating materials (dielectric insulation) . 14
5.3 Cable screen materials . 14
5.4 Cable cryostat materials (thermal insulation) . 14
5.5 Cable oversheathing materials (outside cryostat) . 14
6 Cable characteristics . 14
7 Accessory characteristics . 15
8 Test conditions . 16
8.1 Ambient temperature. 16
8.2 Frequency and waveform of power frequency test voltages . 16
8.3 Wave form of impulse test voltages . 16
8.3.1 Lightning impulse voltage . 16
8.3.2 Switching impulse voltage. 16
8.4 Relationship of test voltages to rated voltages . 16
8.5 Cryogen temperature and pressure . 17
9 Routine tests on cables and on prefabricated accessories . 17
9.1 General . 17
9.1.1 Tests on cable core samples . 17
9.1.2 Tests on cable cryostat . 17
9.1.3 Tests on prefabricated accessories . 17
9.2 AC voltage test for cable followed by partial discharge test . 18
9.2.1 General . 18
9.2.2 Procedure . 18
9.2.3 Requirement . 18
9.3 Critical current measurement . 18
9.3.1 General . 18
9.3.2 Procedure . 18
9.3.3 Requirement . 19
9.4 Pressure test . 19
9.4.1 General . 19
9.4.2 Procedure . 19
9.4.3 Requirement . 19
9.5 Vacuum leak test . 19
9.5.1 General . 19

9.5.2 Procedure . 19
9.5.3 Requirement . 19
9.6 Electrical test on oversheath of the cable . 19
9.7 Tests on prefabricated accessories . 19
9.7.1 Voltage test followed by partial discharge test . 19
9.7.2 Pressure test and vacuum leak test . 20
10 Sample tests on cables . 20
10.1 General . 20
10.2 Frequency of tests . 20
10.3 Repetition of tests . 20
10.4 Conductor examination . 20
10.5 Measurement of thickness of cable insulation . 21
10.5.1 General . 21
10.5.2 Procedure . 21
10.5.3 Requirement . 21
10.6 Measurement of thickness of oversheath . 21
10.6.1 General . 21
10.6.2 Requirement . 21
10.7 Measurement of diameters . 21
10.8 Measurement of capacitance . 21
10.9 Lightning impulse voltage test . 22
11 Sample tests on accessories . 22
11.1 Tests on components . 22
11.2 Tests on complete accessory . 22
12 Type tests on cable systems . 23
12.1 General . 23
12.2 Range of type approval . 23
12.3 Summary of type tests . 24
12.4 Electrical type tests on complete cable systems . 24
12.4.1 Test voltage values . 24
12.4.2 Tests and sequence of tests . 24
12.4.3 Bending test . 25
12.4.4 Critical current measurement . 25
12.4.5 Pressure test . 25
12.4.6 Thermal cycle test . 26
12.4.7 Partial discharge test . 26
12.4.8 Tan δ measurement . 26
12.4.9 Load cycle voltage test . 26
12.4.10 Impulse voltage tests . 26
12.4.11 Examination of cable and accessories . 27
12.5 Non-electrical type tests on cable components and on complete cable . 27
12.5.1 Overview on non-electrical type tests. 27
12.5.2 Check of cable construction . 28
12.5.3 Tests for determining the mechanical properties of oversheaths before
and after ageing . 28
12.5.4 Loss of mass test on PVC oversheaths of type ST . 28
12.5.5 Test on PVC oversheaths (ST and ST ) at low temperature . 28
1 2
12.5.6 Heat shock test for PVC oversheaths (ST and ST ) . 29
1 2
– 4 – IEC 63075:2019  IEC 2019
12.5.7 Measurement of carbon black content of black PE oversheaths (ST
and ST ) . 29
12.5.8 Test under fire conditions . 29
12.5.9 Pressure test of cable cryostat . 29
12.5.10 Pressure test of components of accessories . 30
13 Prequalification test of the cable system . 30
14 Type test on cables . 30
15 Type test on accessories . 30
16 Tests after installation . 30
16.1 General . 30
16.2 Tests at ambient temperature . 31
16.2.1 Vacuum test . 31
16.2.2 Pressure test . 31
16.3 Tests at operating temperature . 32
16.3.1 General . 32
16.3.2 DC current test . 32
16.3.3 AC voltage test of the insulation . 32
16.3.4 DC voltage test of the oversheath . 33
Annex A (informative) Cooling system considerations . 37
A.1 Introductory remarks . 37
A.2 Cryogenic refrigeration. 37
A.2.1 General process . 37
A.2.2 General hardware components . 38
A.3 Recommendations for tests after installation . 39
A.3.1 General . 39
A.3.2 Pressure test followed by vacuum leak test. 39
A.3.3 Cooling capacity test and efficiency measurement . 40
A.3.4 Circulation pump mass flow and pressure test . 40
A.3.5 Temperature and pressure control test . 40
A.3.6 Noise measurements . 40
A.3.7 Other measurements . 40
Annex B (normative) Critical current measurement . 41
B.1 Critical current measurement test . 41
B.1.1 General . 41
B.1.2 Procedure . 41
B.1.3 Test method . 41
Annex C (informative) Tests for engineering information . 43
C.1 Overview. 43
C.2 AC loss . 43
C.2.1 General . 43
C.2.2 Electrical method . 43
C.2.3 Calorimetric – vaporization method . 43
C.2.4 Calorimetric – cryogen mass flow method . 43
C.3 Heat invasion of cryostat . 44
C.3.1 General . 44
C.3.2 Calorimetric – vaporization of liquid cryogen . 44
C.3.3 Calorimetric – liquid cryogen mass flow method . 44
C.4 Electrical parameters . 44

C.5 Short-circuit tests (fault current) . 44
Annex D (informative) List of type tests on cable systems . 45
Annex E (normative) Tests on outer protection for joints . 46
E.1 General . 46
E.2 Range of approval. 46
E.3 Voltage tests . 46
E.3.1 General . 46
E.3.2 Assemblies embodying accessories without sheath sectionalizing
insulation . 46
E.3.3 Assemblies embodying sheath sectionalizing insulation . 46
E.4 Examination of test assembly . 47
Annex F (informative) Prequalification test of the cable system . 48
Bibliography . 49

Figure A.1 – General refrigeration process with indication of temperature and energy
flows . 37
Figure A.2 – General system components and process flow . 39
Figure B.1 – Test setup for electrical four-probe method . 41
Figure B.2 – Voltage-current characteristic for superconductor . 42

Table 1 – Test voltages . 34
Table 2 – Non-electrical type tests for oversheathing compounds for cables . 35
Table 3 – Test requirements for mechanical characteristics of oversheathing

compounds for cables (before and after ageing) . 36
Table 4 – Test requirements for particular characteristics of PVC oversheathing for
cables . 36
Table D.1 – Type tests on cable systems . 45
Table E.1 – Impulse voltage tests . 47

– 6 – IEC 63075:2019  IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SUPERCONDUCTING AC POWER CABLES AND THEIR ACCESSORIES
FOR RATED VOLTAGES FROM 6 KV TO 500 KV –
TEST METHODS AND REQUIREMENTS
FOREWORD
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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 63075 has been prepared by IEC technical committee 20: Electric
cables.
The text of this International Standard is based on the following documents:
FDIS Report on voting
20/1858/FDIS 20/1865/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.

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.
A bilingual version of this publication may be issued at a later date.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 8 – IEC 63075:2019  IEC 2019
INTRODUCTION
As a result of major developments in superconducting cable systems with cold dielectric for
medium- and high-voltage AC applications, CIGRE study committee B1 set up working group
(WG) B1.31 in 2009 with the aim to prepare recommendations for testing superconducting AC
cable systems for power transmission at a rated voltage of up to 150 kV.
The recommendations of CIGRE WG B1.31 were published in TB 538 in June 2013 [1] . At
the time of preparation of the CIGRE recommendation, laboratory experience at voltages up
to and including 275 kV was available, but operating experience was limited to 154 kV. At the
time of preparation of this document, several projects up to 220 kV are in progress, and many
others are planned for the near future. As the insulation system of high-temperature
superconducting (HTS) cable systems considered in this document is comparable to oil-filled
cable systems, it was agreed to extend the voltage range to 500 kV in order to be compatible
with IEC 60141-1 [2].
In 2014, TC 20 decided to start the standardization work on testing of HTS AC cables based
on the published CIGRE TB 538. Manufacturers of HTS cable systems, utilities as the main
users, and independent test laboratories will benefit from this document.
A list of relevant references is given in the Bibliography (see [3], [4], [5], [6]).

__________
Numbers in square brackets refer to the Bibliography.

SUPERCONDUCTING AC POWER CABLES AND THEIR ACCESSORIES
FOR RATED VOLTAGES FROM 6 KV TO 500 KV –
TEST METHODS AND REQUIREMENTS
1 Scope
This document specifies test methods and requirements for high-temperature superconducting
(HTS) AC power cable systems, cables and their accessories, for fixed installations, for rated
voltages from 6 kV (U = 7,2 kV) up to and including 500 kV (U = 550 kV).
m m
The requirements apply to single-core, three-core and three-phase concentric cables with cold
dielectric and their accessories that are not intended for fault current limitation purposes.
This document does not cover special cables and their accessories, such as fault current
limiting cables or submarine cables, for which modifications to the standard tests may be
necessary or special test conditions may need to be devised.
This document does not cover test methods and requirements for the cooling system.
NOTE For considerations regarding cooling systems, refer to Annex A.
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 60060-1, High-voltage test techniques – Part 1: General definitions and test requirements
IEC 60229:2007, Electric cables – Tests on extruded oversheaths with a special protective
function
IEC 60230, Impulse tests on cables and their accessories
IEC 60332-1-2, Tests on electric and optical fibre cables under fire conditions – Part 1-2: Test
for vertical flame propagation for a single insulated wire or cable – Procedure for 1 kW pre-
mixed flame
IEC 60811-202, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 202: General tests – Measurement of thickness of non-metallic sheath
IEC 60811-203, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 203: General tests – Measurement of overall dimensions
IEC 60811-401, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 401: Miscellaneous tests – Thermal ageing methods. Ageing in an air oven
IEC 60811-409, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 409: Miscellaneous tests – Loss of mass test for thermoplastic insulations and sheaths

– 10 – IEC 63075:2019  IEC 2019
IEC 60811-501, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 501: Mechanical tests – Tests for determining the mechanical properties of insulation and
sheathing compounds
IEC 60811-505, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 505: Mechanical tests – Elongation at low temperature for insulations and sheaths
IEC 60811-506, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 506: Mechanical tests – Impact test at low temperature for PVC insulations and sheaths
IEC 60811-508, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 508: Mechanical tests – Pressure test at high temperature for insulations and sheaths
IEC 60811-509, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 509: Mechanical tests – Tests for resistance of insulations and sheaths to cracking (heat
shock test)
IEC 60811-605, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 605: Physical tests – Measurement of carbon black and/or mineral filler in polyethylene
compounds
IEC 60885-3, Electrical test methods for electric cables – Part 3: Test methods for partial
discharge measurements on lengths of extruded power cables
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 Definitions of dimensional values (thicknesses, cross-sections, etc.)
3.1.1
nominal value
value by which a quantity is designated and which is often used in tables
Note 1 to entry: In this document, nominal values usually give rise to values to be checked by measurements,
taking into account specified tolerances.
3.1.2
median value
middle value if the number of available values is odd, and mean of the two middle values if
the number is even, when several test results have been obtained and ordered in an
increasing (or decreasing) succession
3.2 Definitions concerning tests
3.2.1
routine test
test made by the manufacturer on each manufactured cable system component to check that
the component meets the specified requirements

3.2.2
sample test
test made by the manufacturer on samples of complete cable, or components taken from a
complete cable or accessory, at a specified frequency, so as to verify that the finished product
meets the specified requirements
3.2.3
type test
test made before supplying, on a general commercial basis, a type of cable system covered
by IEC 63075, in order to demonstrate satisfactory performance characteristics to meet the
intended application
Note 1 to entry: Once successfully completed, these tests need not be repeated, unless changes are made in the
cable or accessory with respect to materials, manufacturing process, design or design electrical stress levels,
which might adversely change the performance characteristics.
3.2.4
prequalification test
test made before supplying, on a general commercial basis, a type of cable system covered
by IEC 63075, in order to demonstrate satisfactory long-term performance of the complete
cable system
3.2.4
extension of prequalification test
test made before supplying, on a general commercial basis, a type of cable system covered
by IEC 63075, in order to demonstrate satisfactory long-term performance of the complete
cable system, taking into account an already prequalified cable system
3.2.5
test after installation
test made to demonstrate the integrity of the cable system as installed
3.3 Other definitions (general design and cryogenic system)
3.3.1
cable system
cable with installed terminations and/or joints
3.3.2
nominal electrical stress
electrical stress calculated at U using nominal dimensions
3.3.3
high-temperature superconductor
HTS
class of superconductors with a critical temperature generally higher than about 25 K
[SOURCE: IEC 60050-815:2015, 815-11-11] [7]
3.3.4
HTS cable
cable comprising one or more phase conductors consisting of HTS material and a cryostat
Note 1 to entry: An HTS cable can be a single-core, a three-core and a three-phase concentric cable, all within a
common cryostat.
3.3.5
cold dielectric
dielectric material which operates within a cryogenic environment

– 12 – IEC 63075:2019  IEC 2019
3.3.6
HTS cable core
either one or three concentrically arranged phase conductors consisting of HTS material with
cold dielectric insulation and a screen
Note 1 to entry: A screen consists of metal or HTS material, or both.
3.3.7
single-core HTS cable
cable with HTS cable core comprising one phase conductor placed in a cryostat
3.3.8
three-core HTS cable
cable with three HTS cable cores, each comprising one phase conductor placed in a common
cryostat
3.3.9
three-phase concentric HTS cable
cable with an HTS cable core comprising three concentric phase conductors placed in a
cryostat
3.3.10
cryostat
container that provides the cryogenic environmental conditions to operate a superconducting
device
[SOURCE: IEC 60050-815:2015, 815-15-51]
3.3.11
termination
device fitted to the end of a cable to ensure electrical connection with other parts of the
system and to maintain the insulation up to the point of connection
Note 1 to entry: The termination is also an interface between cryogenic temperature and ambient temperature.
Note 2 to entry: The termination could also comprise an interface to the cooling system.
[SOURCE: IEC 60050-461:2008, 461-10-01, modified – The notes to entry have been added.]
3.3.12
joint
accessory making a connection between two HTS cables to form a continuous electrical
circuit and a continuous thermal insulation
Note 1 to entry: The joint could also comprise an interface to the cooling system.
3.3.13
critical current
I
c
maximum direct current that can be regarded as flowing without resistance practically
Note 1 to entry: I is a function of magnetic field strength and temperature.
c
[SOURCE: IEC 60050-815:2015, 815-12-01, modified – "and strain" has been deleted from
Note 1 to entry.]
3.3.14
fault current limiting cable
HTS cable that limits fault currents to acceptable values

3.3.15
AC loss
power dissipated in an HTS cable core owing to application of a time-varying magnetic field,
electric current or voltage
Note 1 to entry: AC loss includes time average hysteresis loss of the HTS material, a coupling current loss and an
eddy current loss of the conductor, an eddy current loss of the structural material, and a dielectric loss of the
electric insulation.
Note 2 to entry: AC loss customarily also includes the power dissipated in the HTS material owing to application
of transient changes in magnetic field or current.
3.3.16
cryogenics
study of the production and behaviour of materials at temperatures below 120 K
3.3.17
cryogen
liquid that boils at cryogenic temperatures below 120 K and is used to obtain very low
temperatures
Note 1 to entry: The most common cryogen for HTS cables is liquid nitrogen due to its availability, cost and
dielectric properties.
3.3.18
cryogenic refrigeration system
cryogenic cooling system
system that is capable of cooling cryogen at cryogenic temperatures
3.3.19
maximum allowable working pressure
maximum pressure (gauge) across the entire operating and testing temperature range to
which the superconducting cable system may be exposed and operated
Note 1 to entry: The maximum allowable working pressure is referred to for pressure testing.
Note 2 to entry: The maximum allowable working pressure includes pressure variations within the normal
operation.
Note 3 to entry: The maximum operating pressure shall be less or equal to the maximum allowable working
pressure.
4 Voltage and current designations
4.1 Rated voltages
In this document, the symbols U , U and U are used to designate the rated voltages of
0 m
cables and accessories, where these symbols have the meanings given in IEC 60183 [9].
4.2 Rated operating current
In this document, the symbol I is used to designate the rated operating current of the cable
r
and accessories. The rated operating current is the RMS value of the current that the system
shall be able to carry continuously under specified conditions of the cryogen. Preferably,
current ratings in accordance with IEC 60059 [10] should be applied.

– 14 – IEC 63075:2019  IEC 2019
5 Cable materials
5.1 Cable conductor materials
This document is applicable to cables having a conductor consisting of HTS material. In
addition, the cable conductor may comprise metal.
NOTE Commonly used HTS materials for the cable conductor are copper-oxide superconductors (see IEC 60050-
815:2015, 815-11-08) in the form of tapes.
5.2 Cable insulating materials (dielectric insulation)
This document is applicable to cables having a cold dielectric consisting of lapped insulating
tapes impregnated with the cryogen.
NOTE 1 Commonly used insulating tapes are kraft paper, polypropylene laminated paper, etc.
NOTE 2 Commonly used cryogen is liquid nitrogen.
5.3 Cable screen materials
This document is applicable to cables having a screen consisting of either HTS material or
metal or a combination of both.
NOTE Commonly used HTS materials for the cable screen are copper-oxide superconductors (see IEC 60050-
815:2015, 815-11-08) in the form of tapes.
5.4 Cable cryostat materials (thermal insulation)
This document is applicable to cables having a cryostat consisting of an inner envelope at
cryogenic temperature and an outer envelope at ambient temperature with a thermal
insulation in between.
NOTE The cable cryostat generally consists of an inner and outer tube made of stainless steel or aluminium
alloys with a vacuum insulation in between.
5.5 Cable oversheathing materials (outside cryostat)
The oversheath is optional.
If an oversheath is required (e.g. using the cryostat as metal screen), it shall be tested.
Tests are specified for the following types of oversheath:
– ST and ST based on polyvinyl chloride (PVC);
1 2
– ST and ST based on polyethylene (PE).
3 7
The choice of the type of oversheath will depend on the design of the cable and on the
mechanical, thermal and fire constraints during installation and operation.
6 Cable characteristics
For the purposes of carrying out the cable system tests described in this document and
recording the results, the cable shall be identified. The following characteristics shall be
known or declared:
a) name of manufacturer, type, designation and manufacturing date or date code;
b) rated voltage: values shall be given for U , U, U (see 4.1 and 8.4);
0 m
c) rated operating current: value shall be given for I ;
r
d) maximum and minimum operating temperature of cryogen shall be given;

e) maximum and minimum operating pressure of cryogen shall be given;
f) maximum allowable working pressure of the system shall be given;
g) type of HTS material, number of HTS tapes in each phase conductor, if applicable nominal
cross-section and type of metal conductor in each phase conductor, design critical current
of each phase conductor at 77,3 K and function of its temperature dependency;
) (see 5.2);
h) material and minimum thickness of insulation (t
min
i) type of cryogen;
j) if applicable, type of HTS material, number of HTS tapes in cable screen and/or nominal
cross-section and type of metal conductor in cable screen, design critical current of screen
conductor at 77,3 K and function of its temperature dependency;
k) nominal diameter of the cable core (d);
l) nominal inner diameter of the cable cryostat (D );
i
m) material and type of cryostat and type of thermal insulation;
n) if applicable, material and nominal thickness of oversheath;
o) nominal overall diameter of the cable (D) (outside the cryostat or oversheath);
p) nominal inner diameter (d ) and calculated minimum outer diameter (D ) of the insula
...