IEC TS 63291-1:2023

High voltage direct current (HVDC) grid systems and connected converter stations - Guideline and parameter lists for functional specifications - Part 1: Guideline

IEC TS 63291-1:2023 contains guidelines on planning, specification, and execution of multi-vendor HVDC grid systems also referred to as HVDC grids. The terms "HVDC grid systems" or "HVDC grids" are used in this document to describe HVDC systems for power transmission having more than two HVDC stations connected to a common DC circuit. The DC circuit can be of radial or meshed topology or a combination thereof. In this document, the term "HVDC grids" is used.
While this document focuses on requirements specific for HVDC grids, some requirements are considered applicable to all HVDC systems in general, i.e., including point‑to‑point HVDC systems. Existing IEC (e.g. IEC TR 63363-1 [1]), Cigre or other relevant documents have been used for reference as far as possible.
Corresponding to electric power transmission applications, this document is applicable to high voltage systems, i.e. those having typically nominal DC voltages higher than 50 kV with respect to earth are considered in this document.
NOTE While the physical principles of DC networks are basically voltage independent, the technical options for designing equipment get much wider with lower DC voltage levels, e.g. in case of converters or switchgear.
This document covers technical aspects of:
- coordination of HVDC grid and AC systems,
- HVDC grid characteristics,
- HVDC grid control,
- HVDC grid protection,
- AC/DC converter stations,
- HVDC grid installations, including DC switching stations and HVDC transmission lines,
- studies and associated models,
- testing.
Beyond the scope of this document, the following content is proposed for future work:
DC/DC converter stations.

General Information

• Status: Published
• Publication Date: 28-Sep-2023
• ICS: 29.200 - Rectifiers. Convertors. Stabilized power supply
• ICS: 29.240.01 - Power transmission and distribution networks in general
• Technical Committee: TC 115 - High Voltage Direct Current (HVDC) transmission for DC voltages above 100 kV
• Drafting Committee: WG 15 - TC 115/WG 15
• Current Stage: PPUB - Publication issued
• Start Date: 11-Aug-2023
• Completion Date: 29-Sep-2023

Standards Content (Sample)

IEC TS 63291-1 ®
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 1: Guideline
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IEC TS 63291-1 ®
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 1: Guideline
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.200; 29.240.01 ISBN 978-2-8322-7571-9

– 2 – IEC TS 63291-1:2023 © IEC 2023
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
2 Normative references . 10
3 Terms, definitions and abbreviated terms . 11
3.1 Terms and definitions . 11
3.2 Abbreviated terms . 16
4 Coordination of HVDC grid and AC systems . 16
4.1 About HVDC grids . 16
4.2 HVDC grid structure . 17
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 . 20
4.5.1 General . 20
4.5.2 Basic operation functions – Converter normal operation state . 20
4.5.3 Basic operation functions – Converter abnormal operation state . 22
4.5.4 Ancillary services . 23
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 . 32
5.1.4 Attributes of an HVDC station . 33
5.2 Connection modes . 34
5.3 Grid operating states . 34
5.3.1 General . 34
5.3.2 Normal state . 35
5.3.3 Alert state . 35
5.3.4 Emergency state . 35
5.3.5 Blackout state . 35
5.3.6 Restoration . 35
5.4 DC voltages . 35
5.4.1 General . 35
5.4.2 Nominal DC system voltage . 35
5.4.3 Steady-state DC pole voltage . 36
5.4.4 Temporary DC pole voltage . 36
5.4.5 DC neutral bus voltage . 37
5.5 Insulation coordination . 39
5.6 Short-circuit characteristics . 39
5.6.1 Calculation of short-circuit currents in HVDC grids . 39
5.6.2 Short-circuit current design requirements . 41
5.7 Steady-state voltage and current distortions . 41
5.7.1 Emissions and impacts . 41
5.7.2 Rights and obligations of a connectee . 42
5.7.3 Similarities between HVDC grids and AC networks . 43
5.7.4 Voltage and current distortion limits . 44

5.7.5 Allocation of limits to individual connectees . 45
5.7.6 Frequency-dependent DC system impedance . 45
5.8 DC system restoration. 46
5.8.1 General . 46
5.8.2 Post-DC fault recovery . 46
5.8.3 Restoration from blackout . 46
6 HVDC grid control . 47
6.1 Closed-loop control functions . 47
6.1.1 General . 47
6.1.2 Core control functions . 47
6.1.3 Coordinating control functions . 47
6.2 Controller hierarchy . 48
6.2.1 General . 48
6.2.2 Internal converter control . 49
6.2.3 DC node voltage control . 49
6.2.4 Coordinated HVDC grid control . 50
6.2.5 AC/DC grid control . 52
6.3 Propagation of information . 53
6.4 Open-loop controls. 55
6.4.1 Coordination of connection modes between HVDC stations and their
PoC-DC . 55
6.4.2 Operating sequences for HVDC grid installations . 56
6.4.3 Post-DC fault recovery . 56
7 HVDC grid protection . 57
7.1 General . 57
7.2 DC fault separation . 58
7.3 Protection system related installations and equipment . 58
7.3.1 AC/DC converter station . 58
7.3.2 HVDC grid topology and equipment . 59
7.4 HVDC grid protection zones . 59
7.4.1 General . 59
7.4.2 Permanent stop P . 62
7.4.3 Permanent stop PQ . 64
7.4.4 Temporary stop P . 65
7.4.5 Temporary stop PQ . 68
7.4.6 Continued operation . 69
7.4.7 Example of a protection zone matrix . 71
7.5 DC protection . 72
7.5.1 General . 72
7.5.2 DC converter protections . 73
7.5.3 HVDC grid protections . 73
7.5.4 HVDC grid protection communication . 75
8 AC/DC converter stations . 75
8.1 Purpose . 75
8.2 AC/DC converter station types . 75
8.2.1 General . 75
8.2.2 AC/DC converter station type 1 (AC/DC type 1) . 75
8.2.3 AC/DC converter station type 2 (AC/DC type 2) . 75
8.2.4 AC/DC converter station type 3 (AC/DC type 3) . 76

– 4 – IEC TS 63291-1:2023 © IEC 2023
8.2.5 AC/DC converter station type 4 (AC/DC type 4) . 76
8.2.6 AC/DC converter station type 5 (AC/DC type 5) .
...