IEC TR 63502:2024
(Main)Guidelines for parameters measurement of HVDC transmission line
Guidelines for parameters measurement of HVDC transmission line
IEC TR 63502:2024, which is a Technical Report, gives information relevant to the on-site HVDC transmission line parameter measurement. HVDC transmission line can be overhead lines, land or submarine cables, or hybrid lines with overhead line section(s) and cable section(s) (or any combination of these). This document introduces measurement specification, including measurement conditions, safety precautions, measurement instrument, measurement methods, etc., in order to measure the parameters of HVDC overhead transmission line and cable with a DC voltage level above 100 kV.
This document is also relevant to line parameter measurement of earth electrode lines in HVDC power transmission systems.
General Information
Standards Content (Sample)
IEC TR 63502 ®
Edition 1.0 2024-12
TECHNICAL
REPORT
colour
inside
Guidelines for parameters measurement of HVDC transmission line
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.
IEC Secretariat Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.
About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.
IEC publications search - webstore.iec.ch/advsearchform IEC Products & Services Portal - products.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews, graphical symbols and the glossary.
committee, …). It also gives information on projects, replaced With a subscription you will always have access to up to date
and withdrawn publications. content tailored to your needs.
IEC Just Published - webstore.iec.ch/justpublished
Electropedia - www.electropedia.org
Stay up to date on all new IEC publications. Just Published
The world's leading online dictionary on electrotechnology,
details all new publications released. Available online and once
containing more than 22 500 terminological entries in English
a month by email.
and French, with equivalent terms in 25 additional languages.
Also known as the International Electrotechnical Vocabulary
IEC Customer Service Centre - webstore.iec.ch/csc
(IEV) online.
If you wish to give us your feedback on this publication or need
further assistance, please contact the Customer Service
Centre: sales@iec.ch.
IEC TR 63502 ®
Edition 1.0 2024-12
TECHNICAL
REPORT
colour
inside
Guidelines for parameters measurement of HVDC transmission line
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.240.20 ISBN 978-2-8327-0070-9
– 2 – IEC TR 63502:2024 © IEC 2024
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 8
4 General . 9
4.1 Background. 9
4.2 Measurement items . 10
4.3 Measurement conditions . 10
4.4 Safety precautions . 10
4.5 Measurement instruments . 10
5 Induced voltage and induced current measurement . 11
5.1 General . 11
5.2 Induced voltage measurement . 11
5.3 Induced current measurement . 12
6 Insulation resistance measurement . 12
7 Polarity verification . 13
7.1 Polarity verification method using megohmmeter . 13
7.2 Polarity verification method using a battery . 14
8 Measurement of DC resistance . 14
9 Measurement of frequency characteristics of HVDC transmission line . 16
9.1 General . 16
9.2 Differential mode measurement . 17
9.2.1 Measuring the differential mode short-circuit impedance . 17
9.2.2 Measuring the differential mode open-circuit impedance . 17
9.2.3 Calculating the frequency characteristics of differential mode
parameters . 17
9.3 Common mode measurement . 18
9.3.1 Measuring the common mode short-circuit impedance . 18
9.3.2 Measuring the common mode open-circuit impedance . 18
9.3.3 Calculating the frequency characteristics at common mode parameters . 19
9.4 Calculating the coupling parameters of pole line I and pole line II . 20
10 Measurement of coupling parameters of two bipolar HVDC transmission lines . 20
10.1 Measuring frequency characteristics at differential mode measurement . 20
10.2 Measuring frequency characteristics at common mode measurement. 21
10.3 Calculating the mutual coupling parameters . 22
11 Measurement of frequency characteristics of HVDC transmission line with
dedicated metallic return line . 22
12 Measurement of frequency characteristics of HVDC cable . 24
13 Measurement of earth electrode line parameter . 24
Annex A (informative) Anti-interference measures . 26
Annex B (informative) Method for locating faults of transmission line . 27
B.1 Overview. 27
B.2 Location of earthing faults . 27
B.3 Location of open-circuit faults . 28
B.4 Location of bipolar short-circuit faults . 28
B.5 Location of multiple faults . 29
Annex C (informative) Principle of measuring distributed parameters . 30
C.1 Distributed parameter circuit of the transmission line . 30
C.2 Definitions. 30
C.3 Telegraph equations . 30
C.4 Calculation of distributed parameters . 31
Annex D (informative) Case of measurement of transmission line parameters . 33
D.1 Base data . 33
D.2 Calculating process . 34
D.2.1 General . 34
D.2.2 Calculation of characteristic impedance and transmission constant . 34
D.2.3 Calculation of per unit length value of impedance and admittance . 34
D.2.4 Calculation of parameter in unit length . 35
D.3 Calculation of parameter in unit length under each selected frequency . 35
D.4 Curve fitting . 36
D.4.1 General . 36
D.4.2 R-f curve under the bipolar parallel measuring mode. 36
D.4.3 L-f curve under the bipolar parallel measuring mode . 36
Bibliography . 38
Figure 1 – Induced voltage test with the ending terminal open-circuited . 11
Figure 2 – Induced voltage test with the ending terminal short-circuited . 12
Figure 3 –Induced current test . 12
Figure 4 – Insulation resistance test of pole line I . 13
Figure 5 – Polarity verification of pole line I . 13
Figure 6 – Polarity verification for pole I using battery . 14
Figure 7 – Measurement of DC resistance . 15
Figure 8 – Measurement of DC resistance with dedicated metallic return . 15
Figure 9 – Measurement of differential mode short-circuit impedance . 17
Figure 10 – Measurement of differential mode open-circuit impedance . 17
Figure 11 – Measurement of common mode short-circuit impedance. 19
Figure 12 – Measurement of common mode open-circuit impedance . 19
Figure 13 – Measurement of differential mode short circuit impedance for two bipolar
transmission lines . 21
Figure 14 – Measurement of differential mode open circuit impedance for two bipolar
transmission lines . 21
Figure 15 – Measurement of common mode short circuit impedance for two bipolar
transmission line . 22
Figure 16 – Measurement of common mode open circuit impedance for two bipolar
transmission line . 22
Figure 17 – Measurement of differential mode short-circuit impedance with metallic
return line . 23
Figure 18 – Measurement of differential mode open-circuit impedance with metallic
return line . 23
Figure 19 – Measurement of common mode short-circuit impedance with metallic
return line . 23
– 4 – IEC TR 63502:2024 © IEC 2024
Figure 20 – Measurement of common mode open-circuit impedance with metallic
return line . 24
Figure 21 – Measurement of common mode short-circuit impedance of HVDC cable . 24
Figure 22 – Measurement of common mode open-circuit impedance of HVDC cable . 24
Figure 23 – Equivalent circuit of earth electrode line . 25
Figure A.1 – Anti-interference measures . 26
Figure B.1 – Location of earthing faults . 27
Figure B.2 – Location of open-circuit faults . 28
Figure B.3 – Location of bipolar short circuit faults . 28
Figure C.1 – Distributed parameter circuit of the transmission line . 30
Figure D.1 – R-f curve under the bipolar parallel measuring mode . 36
Figure D.2 – L-f curve under the bipolar parallel measuring mode . 37
Table D.1 – Open circuit impedance and short circuit impedance under the bipolar
parallel measuring mode . 33
Table D.2 –Line parameters within 30 Hz, 2 500 Hz . 35
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
GUIDELINES FOR PARAMETERS MEASUREMENT OF
HVDC TRANSMISSION LINE
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
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) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC TR 63502 has been prepared by IEC technical committee TC 115: High Voltage Direct
Current (HVDC) transmission for DC voltages above 100 kV. It is a Technical Report.
The text of this Technical Report is based on the following documents:
Draft Report on voting
115/374/DTR 115/386/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.
– 6 – IEC TR 63502:2024 © IEC 2024
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/publications.
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, or
• revised.
IMPORTANT – The "colour inside" logo on the cover page of this document 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.
INTRODUCTION
The development of global clean energy exacerbates uneven distributions of electrical energy,
which intensifies the demand for HVDC transmission techniques as a high-efficiency long-
distance transmission solution of the energy. Parameters of DC lines (e.g. overhead lines,
cables, or their combination) are essential in modelling transmission lines in computations, of
which the accuracy greatly affects the analysis results of the DC transmission system and the
correctness of determining operating strategies. However, the parameters of DC lines are
sensitive to the geological structures, weather characteristics along the transmission corridors,
earthing modes and other uncertainties, which make the theoretical values of parameters invalid.
Thus, on-site measurement is important.
The parameter testing of DC lines is generally carried out after the construction or renovation
of DC projects. The measured parameters of DC transmission lines are important for several
applications, mainly including DC transmission system steady-state calculation, transient
calculation, fault analysis, electromagnetic environment calculation, construction quality
assessment after newly launched HVDC project or renovation, etc. The test results of line
parameters can be used to verify whether the actual parameters meet the requirements of
engineering design. In steady-state calculation, DC resistance is generally used for power flow
computation, voltage drop computation, and resistance loss computation under different
operating modes. In transient calculation, the resistance, capacitance, inductance of the DC
line in per-unit length and its frequency characteristics are essential in performing the over-
voltage calculations under lightning strike, operation, fault, and other working conditions. In
electromagnetic environment calculation, the capacitance analysis of the DC line is the
prerequisite for the calculations of the surface electric field for the wire, the nominal electric
field and ion flow electric field generated by the DC line in the surrounding space, which further
give the important performance data of the DC line, including audible noise, radio interference,
corona loss, etc.
Based on the accurate descriptions of DC line parameters, considering the actual needs of the
above applications, the main DC line parameters described in this document are the DC
resistance and frequency characteristics. Frequency characteristics refer to the response of
line resistance per unit length, inductance, and capacitance as well as the necessary coupling
capacitance and inductance under different frequencies.
This document introduces measurement specification, including measurement conditions,
safety precautions, measurement instruments, measurement methods, etc., in order to measure
the parameters of HVDC overhead transmission line and cable with a DC voltage level above
100 kV.
– 8 – IEC TR 63502:2024 © IEC 2024
GUIDELINES FOR PARAMETERS MEASUREMENT OF
HVDC TRANSMISSION LINE
1 Scope
This document gives information relevant to the on-site HVDC transmission line parameter
measurement. HVDC transmission line can be overhead lines, land or submarine cables, or
hybrid lines with overhead line section(s) and cable section(s) (or any combination of these).
This document is also relevant to line parameter measurement of earth electrode lines in HVDC
power transmission 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 terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
source terminal
terminal of a transmission line, at which a power source is applied for the parameter
measurement
[SOURCE: IEC TR 63042-303:2021, 3.2]
3.2
ending terminal
terminal opposite to the source terminal of a transmission line
[SOURCE: IEC TR 63042-303:2021, 3.3]
3.3
parameter in unit length
resistance, inductance, and capacitance per unit length of HVDC transmission line. A length of
1 km is adopted as the unit length of a transmission line
3.4
frequency characteristics
parameters in unit length changing with different signal frequencies
3.5
induced voltage
voltage caused by electromagnetic or electrostatic effect of adjacent energized lines or
equipment
[SOURCE: IEC TR 63042-303:2021, 3.7]
3.6
induced current
electric current resulting from the displacement of charge carriers due to an induced voltage
[SOURCE: IEC 60050-121:2008, 121-11-29]
3.7
differential mode measurement
applying two-phase signals with equal amplitude and opposite phase into bipolar line to
measure the parameters of HVDC transmission line
3.8
common mode measurement
applying single-phase signal into bipolar line to measure the parameters of HVDC transmission
line
3.9
differential mode short-circuit impedance
input complex impedance of the measured line with the ending terminal short-circuited in
differential mode measurement
3.10
differential mode open-circuit impedance
input complex impedance of the measured line with ending terminal open-circuited in differential
mode measurement
3.11
common mode short-circuit impedance
input complex impedance of the measured line with the ending terminal short-circuited in
common mode measurement
3.12
common mode open-circuit impedance
input complex impedance of the measured line with the ending terminal open-circuited in
common mode measurement
3.13
signal connecting line
test wire connecting the measured line with test equipment and earthing devices
4 General
4.1 Background
The theoretical parameters of DC transmission lines can be invalidated by the varieties of soil
resistivity and tower configurations caused by various terrains that DC transmission lines pass
through, including mountains, rivers, plains, etc. Therefore, it is essential to obtain accurate
parameters of DC lines through on-site measurement. To ensure the smooth progress of on-
site measurement works and the accuracy of measurement results, this document has been
prepared to clearly introduce the measuring items, measuring methods, measuring tools,
measuring processes, and safety precautions.
– 10 – IEC TR 63502:2024 © IEC 2024
4.2 Measurement items
– Induced voltage and induced current
– Insulation resistance
– Polarity verification
– DC resistance
– Frequency characteristics
4.3 Measurement conditions
1) Dismantle all temporary earthing wires along the line.
2) Nobody works on the line.
3) Isolate the line from the reactors, capacitors, voltage dividers and other equipment.
4) The parameters of overhead line and cable are measured separately in case of hybrid
transmission line.
5) Earthing grid of the converter station is available to offer the earthing point for the
measurement. The earthing device can be artificially set to provide a potential reference
point for measurements when the test is done remotely.
6) Technically eliminate the effect of the resistance of the signal connecting line from the
measured result when measuring the DC resistance.
7) Record the earthing status of adjacent transmission lines, as they can affect the result of
the measurement.
4.4 Safety precautions
1) It is important to take anti-interference measures to reduce the induced voltage or induced
current, thus improving the safety of personnel or equipment. See Annex A for details.
2) Keep the line earthed when dismantling or assembling the test wires and use the earthing
switch to short-circuit the ending terminal of the line.
3) Reliably connect the signal line, earthing wire and other wires. Keep the test wires
sufficiently insulated to withstand test voltage and induced voltage.
4) Postpone the measurement if there are unfavourable weather conditions, such as
thunderstorm, rain, snow, etc. Environmental data, such as temperature, humidity, and
atmospheric pressure, also need to be recorded.
5) To protect the personnel and equipment from the lightning strike imposed on the measured
line during the measurement, a safety spark gap is used between the signal line and earthing
wire.
6) Use insulating gloves, insulating boots, insulating mat and other protective equipment to
protect test personnel.
4.5 Measurement instruments
1) Before the measurement, the induced voltage and current can be estimated by the
simulation calculation, in order to help select a suitable range of the voltmeters and
ammeters.
2) The resistance-capacitance divider is used when testing the induced voltage.
3) A megohmmeter with a source voltage of higher than 5 kV is used in testing the insulation
resistance.
4) The uncertainty of the DC resistance device is 0,5 % or lower, which can be determined
based on the method of IEC Guide 115:2023.
5) The frequency range of the test power supply used for measuring the frequency
characteristics covers the interval of 30 Hz to 2 500 Hz. In order to improve measurement
accuracy, the measurement frequency points can avoid the inherent resonant frequency of
the measured line. The voltage output of the test power supply is not less than 300 V and
the current output is not less than 3 A.
6) The uncertainty of the Hall transducer (HT) is 1 % or lower, which can be determined based
on the method of IEC Guide 115:2023. The frequency range of the current transformer (CT)
covers the interval of 30 Hz to 2 500 Hz.
7) The uncertainty of the potential transformer (PT) is 0,5 % or lower, which can be determined
based on the method of IEC Guide 115:2023. The frequency range of the PT covers the
interval of 30 Hz to 2 500 Hz.
5 Induced voltage and induced current measurement
5.1 General
For the safety considerations, the induced voltage is first measured before line parameters
measurements. The induced voltage and current are mainly caused by adjacent live AC/DC
lines, of which the amplitude and frequency are comprehensively determined by the electrical
geometric parameters of adjacent lines, weather conditions, geomagnetic storms, etc. Thus, it
is difficult to accurately determine the induced voltage and current by theoretical calculations,
which necessitates the on-site measurements. These measurements will form the basis for the
succeeding works regarding anti-interference and safety.
Owing to the fact that the potential induced voltage might be beyond several tens of kV, the
range of the measuring device would typically be in the range of 100 kV.
5.2 Induced voltage measurement
The induced voltage measurement is conducted at two pole lines separately. As shown in
Figure 1, the measurement is performed at the source terminal by a resistance-capacitance
divider and a voltmeter or an oscilloscope, with the ending terminal remaining open.
Figure 1 – Induced voltage test with the ending terminal open-circuited
Afterwards, the measurement is performed at the source terminal with the ending terminals of
two pole lines shorted and earthed, as shown in Figure 2. The induced voltage of pole line I and
pole line II are measured and recorded in the same way as mentioned above.
– 12 – IEC TR 63502:2024 © IEC 2024
Figure 2 – Induced voltage test with the ending terminal short-circuited
5.3 Induced current measurement
The induced current is measured at the source terminal with ending terminal shorted and
earthed as shown in Figure 3. The ammeter or the oscilloscope can be used to measure and
record the induced current.
Figure 3 –Induced current test
6 Insula
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...