IEC TS 63291-2:2023

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
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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

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 .
...