IEC TR 61901:2016

IEC TR 61901 ®
Edition 2.0 2016-05
TECHNICAL
REPORT
Tests recommended on cables with a longitudinally applied metal foil for rated
voltages above 30 kV (U = 36 kV) up to and including 500 kV (U = 550 kV)
m m
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IEC TR 61901 ®
Edition 2.0 2016-05
TECHNICAL
REPORT
Tests recommended on cables with a longitudinally applied metal foil for rated

voltages above 30 kV (U = 36 kV) up to and including 500 kV (U = 550 kV)
m m
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.060.20 ISBN 978-2-8322-3386-3

– 2 – IEC TR 61901:2016 © IEC 2016
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references. 7
3 Terms and definitions . 7
3.1 Definitions concerning the tests . 7
3.2 Definitions concerning cable design . 8
3.3 Other definitions . 8
4 Development tests . 8
4.1 Tests on cables . 8
4.1.1 Impact test . 8
4.1.2 Abrasion test. 10
4.1.3 Sidewall loading test . 11
4.1.4 Long-term ageing of adhesive bonds of components of laminated
covering . 13
4.1.5 Mechanical properties of the weld (case of CD design) . 13
4.2 Tests on cable systems . 14
4.2.1 General . 14
4.2.2 Short-circuit test. 15
4.2.3 Corrosion at the accessories . 18
5 Type tests . 18
5.1 Test on cables – Bending test . 18
5.2 Tests on cable system . 19
6 Sample test on cables . 19
6.1 Adhesion and peel strength of the laminated metal foil . 19
6.2 Electrical properties and dimensions . 21
7 Routine tests . 21
8 After installation tests . 21
Annex A (informative) Details on cable designs given in 3.2 . 22
A.1 Combined design (CD) . 22
A.2 Separate design (SD) . 22
A.3 Separate semi-conductive design (SscD) . 23
Bibliography . 25

Figure 1 – Test apparatus for the impact test . 9
Figure 2 – Positions of the points of impact . 9
Figure 3 – Deformation at the impact points to be examined . 10
Figure 4 – Test arrangement for the abrasion test . 11
Figure 5 – Sidewall loading test arrangements . 12
Figure 6 – Test arrangement for the measurement of the mechanical properties of the weld . 14
Figure 7 – Short-circuit test arrangement for three kinds of joints . 16
Figure 8 – Adhesion of metal foil . 20
Figure 9 – Example of overlapped metal foil . 21
Figure 10 – Peel strength of overlapped metal foil . 21

Figure A.1 – Example of combined design 500 kV cable . 22
Figure A.2 – Example of separate design 400 kV cable . 23
Figure A.3 – Example of separate semi-conductive design 275 kV cable . 24

Table 1 – Impact test requirements . 9
Table 2 – Maximum acceptable sidewall loadings . 11
Table 3 – Minimum acceptable adhesion or peel strength forces . 19

– 4 – IEC TR 61901:2016 © IEC 2016
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
TESTS RECOMMENDED ON CABLES WITH A LONGITUDINALLY
APPLIED METAL FOIL FOR RATED VOLTAGES ABOVE 30 kV
(U = 36 kV) UP TO AND INCLUDING 500 kV (U = 550 kV)
m m
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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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
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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.
The main task of IEC technical committees is to prepare International Standards. However, a
technical committee may propose the publication of a Technical Report when it has collected
data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC TR 61901, which is a Technical Report, has been prepared by IEC technical committee
20: Electric cables.
This second edition cancels and replaces the first edition, published in 2005. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Recommendations on the tests to be performed at the different stages of the cable and
cable system qualification (development tests, type tests, sample tests, routine tests, after
installation tests) have been provided.

b) The performance level of the tests related to the longitudinally applied metal foil which
depends on the cable design has been detailed.
c) Three cable designs that represent the world production of cables with longitudinally
applied metal foil have been detailed.
d) A test on the weld design has been included, following the appearance of a new cable
design with smooth and longitudinally welded aluminium foil (referred to in this document
as combined design).
e) An examination of the cable at the end of the type test has been included.
f) The cable system approach (cable with installed accessories) has been considered and a
short circuit test with accessories has been introduced.
The text of this Technical Report is based on the following documents:
Enquiry draft Report on voting
20/1551/DTR 20/1621/RVC
Full information on the voting for the approval of this Technical Report can be found in the
report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

– 6 – IEC TR 61901:2016 © IEC 2016
INTRODUCTION
Numerous technical improvements have appeared on laminated coverings since 1992 and the
publication of CIGRE Electra 141[1] , in parallel with service experience. In 2006, CIGRE
requested an upgrade of Electra 141 which was issued in February 2011 as Technical
Brochure 446[2].
This new data was analysed and resulted in the revision of the first edition of IEC TR 61901.

___________
Numbers in brackets refer to the Bibliography.

TESTS RECOMMENDED ON CABLES WITH A LONGITUDINALLY
APPLIED METAL FOIL FOR RATED VOLTAGES ABOVE 30 kV
(U = 36 kV) UP TO AND INCLUDING 500 kV (U = 550 kV)
m m
1 Scope
IEC TR 61901, which is a Technical Report, specifies test methods and requirements for
power cable systems, cables with extruded insulation and their accessories for fixed
installations, for rated voltages above 30 kV (U = 36 kV) up to and including 500 kV
m
(U = 550 kV).
m
The requirements apply to single-core cables and to their accessories for usual conditions of
installation and operation, but not to special cables and their accessories, such as submarine
cables, for which modifications to the tests may be necessary or special test conditions may
need to be devised.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 Definitions concerning the tests
3.1.1
routine test
test made by the manufacturer on each manufactured component (length of cable or
accessory) to check that the component meets the specified requirements
3.1.2
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
3.1.3
development test
test made during the development of the cable system
3.1.4
type test
test made before supplying on a general commercial basis a type of cable system in order to
demonstrate satisfactory performance characteristics to meet the intended application

– 8 – IEC TR 61901:2016 © IEC 2016
Note 1 to entry: Once successfully completed, these tests need not be repeated, unless changes are made in the
cable or accessory materials, or design or manufacturing process which might change the performance
characteristics.
3.1.5
prequalification test
test made before supplying on a general commercial basis a type of cable system in order to
demonstrate satisfactory long term performance of the complete cable system
3.1.6
electrical test after installation
test made to demonstrate the integrity of the cable system as installed
3.2 Definitions concerning cable design
NOTE The following explanations are definitions of general designs types and not related to any specific
construction specified in any IEC standard. Technological advances may lead to developments of these examples.
3.2.1
combined design
CD
metal screen that combines radial watertightness and electrical properties
Note 1 to entry: More details are given in Clause A.1.
3.2.2
separate design
SD
design with radial watertightness and electrical properties, managed by different metal
components
Note 1 to entry: More details are given in Clause A.2.
3.2.3
separate semi-conductive design
SscD
design with separated electrical and radial watertightness properties with semi-conductive
plastic coated foil
Note 1 to entry: More details are given in Clause A.3.
3.3 Other definitions
3.3.1
cable system
cable with installed accessories including components used for thermomechanical restraint of
systems limited to those used for terminations and joints only
4 Development tests
4.1 Tests on cables
4.1.1 Impact test
There are three classes for resistance of the cable sheath to mechanical impact depending on
the design and installation conditions of the cable, see Table 1.

Table 1 – Impact test requirements
a
Impact test Design CD Design SD Design SscD
Height (m) 0,27 1 N/A
Weight (kg) 27 5 N/A
Radius (R) (mm) 1 2 N/A
Number of impacts 4 impacts per location 1 impact per location N/A
per location
Number of locations 2 different points (see 5 different points more N/A
Figure 2 for locations) than 100 mm apart
a
Impact test is not needed as this cable design is not intended to be directly buried.

R
IEC
Figure 1 – Test apparatus for the impact test
Sample: A piece of cable, at least 1 m in length.
Test:
a) Test on CD design
The cable should be installed on a rigid metal base.
The test should be undertaken at a temperature of (20 ± 15) °C using a weighted metal of
27 kg, wedge of 90°, falling onto the cable from a height of 0,27 m. The wedge should
have a radius of curvature of R = 1 mm at the point of impact and its axis should be
perpendicular to that of the cable (Figure 1).
The requirements for the impact test are presented in Table 1.
The test should be performed on the overlap or on the welded seam (Impact point A) and
on the opposite side of the cable (Impact point B) (see Figure 2).
A
B
IEC
Figure 2 – Positions of the points of impact
Result: Visual inspection and measurement of impact depth.

– 10 – IEC TR 61901:2016 © IEC 2016
After the impacts, the sample should be cut longitudinally along two lines at 90° from the
points of impact. The inner side of the metal screen or metal sheath should be examined
with normal vision:
– there should be no puncture at the points of impact A and B;
– a longitudinal cut should be made through the points of impact A and B (Figure 3). The
insulation should not be deformed by more than 1 mm (distance d, see Figure 3) and
should not show a deflection having a sharp angle into the insulation at the point of
impact.
IEC
Key
1 oversheath
2 screen or metal sheath
3 outer semiconductive layer
4 penetration into the insulation
Figure 3 – Deformation at the impact points to be examined
b) Test on SD design
The cable, at least 1 m in length, should be installed on a rigid metallic base. The test
should be undertaken at (20 ± 15) °C using a weighted metal wedge of 5 kg falling onto
the cable from a height of 1 m. The 90° wedge should have a radius of curvature of
R = 2 mm at the point of impact and its axis should be perpendicular to that of the cable
(Figure 1).
An impact should be successively made at five different points along the cable; the
distance between any two impact points should be at least 100 mm.
Result: Visual inspection
A 1 m sample should be dissected and visually examined. Examination of the samples
with normal or corrected vision without magnification should reveal no cracks or
separation of the metal foil of laminated protective coverings or harmful damage to other
parts of the cable.
c) Test on SscD design
No test is needed due to the specific installation conditions.
4.1.2 Abrasion test
The abrasion test should be carried out if the oversheath material is not of type S
...