CLC IEC/TS 63291-2:2025

SLOVENSKI STANDARD
01-november-2025
Sistemi visokonapetostnega enosmernega omrežja in priključene pretvorniške
postaje - Smernice in seznam parametrov za funkcijsko specifikacijo - 2. del:
Seznam parametrov
High voltage direct current (HVDC) grid systems and connected converter stations -
Guideline and parameter lists for functional specifications - Part 2: Parameter lists
Hochspannungsgleichstrom-Netzsysteme und angeschlossene Umrichterstationen -
Leitfaden und Parameterlisten für funktionale Spezifikationen - Teil 2: Parameter-Listen
Réseaux en courant continu à haute tension (CCHT) et postes de conversion connectés
- Lignes directrices et listes de paramètres pour les spécifications fonctionnelles - Partie
2: Listes de paramètres
Ta slovenski standard je istoveten z: CLC IEC/TS 63291-2:2025
ICS:
29.200 Usmerniki. Pretvorniki. Rectifiers. Convertors.
Stabilizirano električno Stabilized power supply
napajanje
29.240.01 Omrežja za prenos in Power transmission and
distribucijo električne energije distribution networks in
na splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION CLC IEC/TS 63291-2

SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION September 2025
ICS 29.240.01; 29.200 Supersedes CLC/TS 50654-2:2020
English Version
High voltage direct current (HVDC) grid systems and connected
converter stations - Guideline and parameter lists for functional
specifications - Part 2: Parameter lists
(IEC/TS 63291-2:2023)
Réseaux en courant continu à haute tension (CCHT) et Hochspannungsgleichstrom-Netzsysteme und
postes de conversion connectés - Lignes directrices et angeschlossene Stromrichterstationen - Leitfaden und
listes de paramètres pour les spécifications fonctionnelles - Parameter-Listen für funktionale Spezifikationen - Teil 2:
Partie 2: Listes de paramètres Parameter-Listen
(IEC/TS 63291-2:2023) (IEC/TS 63291-2:2023)
This Technical Specification was approved by CENELEC on 2025-08-26.

CENELEC members are required to announce the existence of this TS in the same way as for an EN and to make the TS available promptly
at national level in an appropriate form. It is permissible to keep conflicting national standards in force.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye 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
© 2025 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. CLC IEC/TS 63291-2:2025 E

European foreword
This document (CLC IEC/TS 63291-2:2025) consists of the text of document IEC/TS 63291-2:2023,
prepared by IEC/TC 115 "High Voltage Direct Current (HVDC) transmission for DC voltages above
100 kV".
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.
This document is read in conjunction with CLC IEC/TS 63291-1:2025.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Technical Specification IEC/TS 63291-2:2023 was approved by CENELEC
as a European Technical Specification without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 60633:2019 NOTE Approved as EN IEC 60633:2019 (not modified)
IEC 61660-1:1997 NOTE Approved as EN 61660-1:1997 (not modified)
IEC 61000-4-7 NOTE Approved as EN 61000-4-7
IEC 61975:2010 NOTE Approved as EN 61975:2010 (not modified)
IEC 61975:2010/A1:2016 NOTE Approved as EN 61975:2010/A1:2017 (not modified)
IEC 60909 (series) NOTE Approved as EN 60909 (series)
IEC 62271-100 NOTE Approved as EN IEC 62271-100
IEC 62271-102 NOTE Approved as EN IEC 62271-102
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.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 62747 2014 Terminology for voltage-sourced converters EN 62747 2014
(VSC) for high-voltage direct current (HVDC)
systems
+ A1 2019 + A1 2019
IEC/TS 63291-1 2023 High voltage direct current (HVDC) grid CLC IEC/TS 63291-1 2025
systems and connected converter stations -
Guideline and parameter lists for functional
specifications - Part 1: Guideline

IEC TS 63291-2 ®
Edition 1.0 2023-09
TECHNICAL
SPECIFICATION
colour
inside
High voltage direct current (HVDC) grid systems and connected converter

stations – Guideline and parameter lists for functional specifications –

Part 2: Parameter lists
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.200; 29.240.01 ISBN 978-2-8322-7572-6

– 2 – IEC TS 63291-2:2023 © IEC 2023
CONTENTS
FOREWORD . 9
INTRODUCTION . 11
1 Scope . 12
2 Normative references . 12
3 Terms, definitions and abbreviated terms . 13
3.1 Terms and definitions . 13
3.2 Abbreviated terms . 17
4 Coordination of HVDC grid and AC systems . 18
4.1 About HVDC grids . 18
4.2 HVDC grid structure . 18
4.3 Purpose of the HVDC grid and power network diagram . 18
4.4 AC/DC power flow optimisation . 19
4.5 Converter operational functions . 21
4.5.1 Basic operation functions – Converter normal operation state . 21
4.5.2 Basic operation functions – Converter abnormal operation state . 22
4.5.3 Ancillary services . 24
5 HVDC grid characteristics . 28
5.1 HVDC circuit topologies . 28
5.1.1 Availability and reliability . 28
5.1.2 Basic characteristics and nomenclature . 28
5.1.3 Attributes of HVDC grids or HVDC grid subsystems . 29
5.1.4 Attributes of an HVDC station . 29
5.2 Connection modes . 30
5.3 Grid operating states . 30
5.3.1 General . 30
5.3.2 Normal state . 30
5.3.3 Alert state . 30
5.3.4 Emergency state . 30
5.3.5 Blackout state . 30
5.3.6 Restoration . 30
5.4 DC voltages . 31
5.4.1 General . 31
5.4.2 Nominal DC system voltage . 32
5.4.3 Steady-state DC pole voltage . 32
5.4.4 Temporary DC pole voltage . 32
5.4.5 DC neutral bus voltage . 33
5.5 Insulation coordination . 35
5.6 Short-circuit characteristics . 35
5.6.1 Calculation of short-circuit currents in HVDC grids . 35
5.6.2 Short-circuit current design requirements . 37
5.7 Steady-state voltage and current distortions . 37
5.7.1 Emissions and impacts . 37
5.7.2 Rights and obligations of a connectee . 39
5.7.3 Similarities between HVDC grids and AC networks . 39
5.7.4 Voltage and current distortion limits . 39
5.7.5 Allocation of limits to individual connectees . 39

IEC TS 63291-2:2023 © IEC 2023 – 3 –
5.7.6 Frequency-dependent DC system impedance . 39
5.8 DC system restoration. 39
5.8.1 General . 39
5.8.2 Post-DC fault recovery . 40
5.8.3 Restoration from blackout . 40
6 HVDC grid control . 40
6.1 Closed-loop control functions . 40
6.1.1 General . 40
6.1.2 Core control functions . 40
6.1.3 Coordinating control functions . 40
6.2 Controller hierarchy . 40
6.2.1 General . 40
6.2.2 Internal converter control . 40
6.2.3 DC node voltage control . 40
6.2.4 Coordinated HVDC grid control . 41
6.2.5 AC/DC grid control . 44
6.3 Propagation of information . 44
6.4 Open-loop controls. 48
6.4.1 Coordination of connection modes between HVDC stations and their
PoC-DC . 48
6.4.2 Operating sequences for HVDC grid installations . 48
6.4.3 Post-DC fault recovery . 49
7 HVDC grid protection . 49
7.1 General . 49
7.2 DC fault separation . 49
7.3 Protection system related installations and equipment . 50
7.3.1 AC/DC converter station . 50
7.3.2 HVDC grid topology and equipment . 50
7.4 HVDC grid protection zones . 50
7.4.1 General . 50
7.4.2 Permanent stop P . 53
7.4.3 Permanent stop PQ . 54
7.4.4 Temporary stop P . 54
7.4.5 Temporary stop PQ . 54
7.4.6 Continued operation . 54
7.4.7 Example of a protection zone matrix . 54
7.5 DC protection . 55
7.5.1 General . 55
7.5.2 DC converter protections . 55
7.5.3 HVDC grid protections . 55
7.5.4 HVDC grid protection communication . 55
8 AC/DC converter stations . 55
8.1 Purpose . 55
8.2 AC/DC converter station types . 55
8.3 Overall requirements . 55
8.3.1 Robustness of AC/DC converter stations . 55
8.3.2 Availability and reliability . 56
8.3.3 Active power reversal . 56

– 4 – IEC TS 63291-2:2023 © IEC 2023
8.4 Main circuit design . 56
8.4.1 General characteristics . 56
8.4.2 DC side . 57
8.4.3 AC side. 62
8.5 HVDC grid control and protection interface . 62
8.6 Controls . 63
8.6.1 General . 63
8.6.2 Automated vs manual operation . 63
8.6.3 Control modes and support of coordination . 63
8.6.4 Limitation strategies . 64
8.6.5 Operating sequences for AC/DC converter station . 65
8.6.6 Dynamic behaviour . 65
8.7 Protection . 66
8.7.1 General . 66
8.7.2 Configuration requirements . 66
8.7.3 Function requirements . 66
8.7.4 Fault separation strategy for faults inside the AC/DC converter station . 66
8.7.5 Coordination of the DC protection with the HVDC grid . 66
8.7.6 Example for coordination of the DC protection with the HVDC grid . 66
9 HVDC grid installations . 66
9.1 General . 66
9.2 DC switching station . 66
9.2.1 Purpose . 66
9.2.2 Overall requirements . 67
9.2.3 Main circuit design . 67
9.2.4 HVDC grid control and protection interface . 74
9.2.5 Controls . 75
9.2.6 Protection . 78
9.3 HVDC transmission lines. 79
9.3.1 Purpose . 79
9.3.2 Overall requirements . 79
9.3.3 Main circuit design . 80
9.3.4 HVDC grid control and protection interface . 82
9.3.5 Controls . 83
9.3.6 Protection . 83
9.4 DC/DC converter stations . 83
10 Studies and associated models . 84
10.1 General . 84
10.2 Description of studies . 84
10.2.1 General . 84
10.2.2 HVDC grid planning studies . 84
10.2.3 HVDC grid design studies . 84
10.2.4 HVDC grid extension studies . 84
10.2.5 Studies for HVDC grid installation refurbishments and other
modifications . 84
10.3 Models and interfaces . 84
10.3.1 General . 84
10.3.2 Model interfaces and integration compatibility . 85
10.3.3 Model capability . 85

IEC TS 63291-2:2023 © IEC 2023 – 5 –
10.3.4 Model format . 85
10.3.5 Model maintenance and portability . 86
10.3.6 Model aggregation . 86
10.3.7 Model testing and validation . 86
11 Testing . 87
11.1 General . 87
11.2 Off-site testing . 88
11.2.1 General . 88
11.2.2 Factory system tests . 88
11.3 On-site testing . 88
Bibliography . 89

Figure 1 – Definition of the point of connection-AC and the point of connection-DC at
an AC/DC converter station . 14
Figure 2 – Rigid bipolar HVDC system . 16
Figure 3 – Generic AC over- and undervoltage ride through profile of an AC/DC
converter station: Different values can be specified for symmetrical and asymmetrical
faults . 24
Figure 4 – Temporary DC pole to earth voltage profiles at a PoC-DC . 31
Figure 5 – Generic neutral bus voltage profile at a PoC-DC . 34
Figure 6 – Standard approximation function . 37
Figure 7 – Typical DC node voltage control modes (illustration in DC voltage/power
plane) . 41
Figure 8 – Generation of final converter schedules including converter control modes
and its parameters . 45
Figure 9 – Propagation of switching commands to individual HVDC stations . 46
Figure 10 – Operating sequences as transitions between operating states . 48
Figure 11 – Example voltage and current traces in the event of "permanent stop" . 51
Figure 12 – Example voltage and current traces in the event of "temporary stop P" . 52
Figure 13 – Example voltage and current traces in the event of "continued operation" . 53

Table 1 – Nomenclature of HVDC circuit topologies . 19
Table 2 – Active and reactive power characteristics for a given AC system voltage
operating range of an AC/DC converter station . 19
Table 3 – Parameters of an HVDC transmission line . 21
Table 4 – Parameter list for AC system frequency following a frequency / power droop
operation of an AC/DC converter station . 21
Table 5 – Parameter list for DC voltage / DC power droop operation of an AC/DC
converter station . 22
Table 6 – Parameters describing the operation conditions of the AC network at an
AC/DC converter station prior to and after a fault . 22
Table 7 – Time requirements for power restoration in the event of temporary faults . 23
Table 8 – AC undervoltage ride through requirements for an AC/DC converter station . 23
Table 9 – AC overvoltage ride through requirements for an AC/DC converter station . 24
Table 10 – Coordination of power associated with primary frequency control . 25
Table 11 – FCR parameters for an AC/DC converter station, parameters for active
power frequency response in FSM . 26

– 6 – IEC TS 63291-2:2023 © IEC 2023
Table 12 – Voltage range capability parameters for an AC/DC converter station . 27
Table 13 – Reactive power capability parameters for an AC/DC converter station . 27
Table 14 – Parameters describing electromechanical oscillations . 27
Table 15 – Parameters describing post-fault active power recovery at an AC/DC
converter station . 28
Table 16 – Characteristics of the HVDC grid . 28
Table 17 – DC circuit earthing parameters . 29
Table 18 – Parameters for each return path . 30
Table 19 – Nominal DC system voltage at a PoC-DC . 32
Table 20 – DC pole voltage range parameters at a PoC-DC of an HVDC station –
Steady-state . 32
Table 21 – DC pole voltage range parameters at a PoC-DC of an HVDC station –
Temporary undervoltages . 32
Table 22 – DC pole voltage range parameters at a PoC-DC of an HVDC station –
Temporary overvoltages . 33
Table 23 – DC neutral bus voltage range parameters . 34
Table 24 – Insulation levels at a PoC-DC . 35
Table 25 – Maximum converter current of an HVDC station into the HVDC grid . 35
Table 26 – Component data – Earthing branch . 36
Table 27 – Component data – Standalone DC capacitors and DC filters of an HVDC
station . 36
Table 28 – Component data – DC line reactors of an HVDC station . 36
a
Table 29 – Component data – DC lines (OHL, cable including electrode lines) . 36
Table 30 – Short-circuit current parameters at a PoC-DC . 37
Table 31 – Equivalent impedances for calculating voltage and current distortions at a
PoC-DC . 38
Table 32 – Pre-existing DC voltage and current distortions at a PoC-DC. 38
Table 33 – Planning levels and permissible DC voltage and current distortions at a
PoC-DC . 38
Table 34 – Coupling factors for calculating voltage distortions at a remote bus caused
by emissions at a PoC-DC . 39
Table 35 – Specification of DC system impedance . 39
Table 36 – DC node voltage control parameters . 41
Table 37 – System state variables and equipment status signals (interface list) . 42
Table 38 – General interface (signal list) for autonomous adaption control rules . 42
Table 39 – General interface (signal list) for defining an observation . 43
Table 40 – General interface (signal list) for defining countermeasures of rules . 43
Table 41 – Interface parameters required from the HVDC grid control layer . 44
Table 42 – General interface (signal list) for orders from TSOs . 44
Table 43 – General interface (signal list) defining a "converter schedule" . 45
Table 44 – General interface (signal list) defining "switching commands" . 46
Table 45 – General signal interface (physical quantities) of the "station information" . 47
Table 46 – General signal interface (control parameters) of the "station information" . 48
Table 47 – Unified description of operating sequences . 49
Table 48 – Parameters for recovery sequences after DC line faults . 49

IEC TS 63291-2:2023 © IEC 2023 – 7 –
Table 49 – Example of an HVDC grid protection zone matrix . 50
Table 50 – DC protection parameter list . 50
Table 51 – DC converter protection parameter list . 55
Table 52 – Converter station topology . 56
Table 53 – Energy dissipation/absorption capability at a PoC . 57
Table 54 – DC connection modes of the AC/DC converter station . 58
Table 55 – DC circuit re-configuration time requirements . 58
Table 56 – Repetition of DC fault events and recovery attempts . 59
Table 57 – DC circuit energisation . 60
Table 58 – Connecting the AC/DC converter station . 60
Table 59 – Disconnecting the AC/DC converter station . 60
Table 60 – DC circuit de-energisation . 61
Table 61 – Parameters for the automatic control interface of the AC/DC converter
station according to standard protocols . 63
Table 62 – Parameters for the automatic control interface of the AC/DC converter

station according to proprietary protocols. 63
Table 63 – Parameters for the available control modes of the AC/DC converter station . 64
Table 64 – Limitation strategies . 65
Table 65 – Operating states and transitions for the AC/DC converter station . 65
Table 66 – Protection coordination of the AC/DC converter station and the HVDC grid
(for main and backup concept including the separation concept and the FSD) . 66
Table 67 – DC switching station topology . 67
Table 68 – Temporary energy dissipation/absorption capability of the DC switching
station . 68
Table 69 – Power flow controlling capability of a DC SU . 68
Table 70 – DC connection modes of a DC SU for PoC-DCx . 69
Table 71 – DC circuit re-configuration time requirements . 69
Table 72 – Repetition of DC fault events and recovery attempts . 71
Table 73 – DC circuit energisation . 72
Table 75 – Disconnecting the DC switching station . 72
Table 76 – DC circuit de-energisation . 73
Table 77 – Parameters for the automatic control interface of the DC switching station
according to standard protocols . 75
Table 78 – Parameters for the automatic control interface of the DC switching station
according to proprietary protocols . 75
Table 79 – Parameters for the available control modes of the DC switching station . 76
Table 80 – Limitation strategies . 77
Table 81 – Operating states and transitions for a SU of the DC switching station . 78
Table 82 – Protection coordination of the DC switching station and the HVDC grid (for
main and backup concept including the separation concept and the FSD) . 79
Table 83 – DC line power transmission parameters for the transmission line including

all different HVDC transmission line sections, if any. 80
Table 84 – Frequency range for specification of DC system impedance . 82
Table 85 – Parameters defining the model generalities . 84

– 8 – IEC TS 63291-2:2023 © IEC 2023
Table 86 – Parameters to characterize the model capability . 85
Table 87 – Parameters to define the model format . 85
Table 88 – Parameters defining the model aggregation . 86
Table 89 – Parameters defining the model validation . 86
Table 90 – Parameters for testing . 87
Table 91 – Minimum set of parameters to be defined for all test scenarios . 87

IEC TS 63291-2:2023 © IEC 2023 – 9 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HIGH VOLTAGE DIRECT CURRENT (HVDC) GRID SYSTEMS AND
CONNECTED CONVERTER STATIONS – GUIDELINE AND PARAMETER
LISTS FOR FUNCTIONAL SPECIFICATIONS –

Part 2: Parameter lists
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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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 TS 63291-2 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 Specification.
The text of this Technical Specification is based on the following documents:
Draft Report on voting
115/320/DTS 115/329/RVDTS
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 Specification is English.
This Technical Specification is to be used in conjunction with IEC TS 63291-1:2023.

– 10 – IEC TS 63291-2:2023 © IEC 2023
A list of all parts in the IEC 63291 series, published under the general title High voltage direct
current (HVDC) grid systems and connected converter stations – Guideline and parameter lists
for functional specifications, can be found on the IEC website.
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
...