IEC TR 60919-1:2020

IEC TR 60919-1 ®
Edition 4.0 2020-04
REDLINE VERSION
TECHNICAL
REPORT
colour
inside
Performance of high-voltage direct current (HVDC) systems with
line‑commutated converters –
Part 1: Steady-state conditions

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IEC TR 60919-1 ®
Edition 4.0 2020-04
REDLINE VERSION
TECHNICAL
REPORT
colour
inside
Performance of high-voltage direct current (HVDC) systems with

line‑commutated converters –
Part 1: Steady-state conditions

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.200; 29.240.99 ISBN 978-2-8322-8226-7

– 2 – IEC TR 60919-1:2020 RLV © 2020
CONTENTS
FOREWORD . 8
INTRODUCTION . 2
1 Scope . 11
2 Normative references . 12
3 Terms and definitions . 12
4 Types of HVDC systems . 12
4.1 General . 12
4.2 HVDC back-to-back system . 13
4.3 Monopolar HVDC system with earth return HVDC system . 13
4.4 Monopolar HVDC system with metallic return HVDC system . 17
4.5 Bipolar earth return HVDC system . 18
4.6 Bipolar HVDC system with metallic return HVDC system . 21
4.7 Two 12-pulse groups per pole . 22
4.8 Converter transformer arrangements . 25
4.9 DC switching considerations . 26
4.10 Series-capacitor-compensated HVDC systems . 29
4.11 LCC/VSC hybrid bipolar system . 33
5 Environment information . 34
6 Rated power, current and voltage . 37
6.1 Rated power . 37
6.1.1 General . 37
6.1.2 Rated power of an HVDC system with transmission line . 37
6.1.3 Rated power of an HVDC back-to-back system . 37
6.1.4 Direction of power flow . 37
6.2 Rated current . 37
6.3 Rated voltage . 38
7 Overload and equipment capability . 38
7.1 Overload . 38
7.2 Equipment capability . 39
7.2.1 General . 39
7.2.2 Converter valve capability . 39
7.2.3 Capability of oil-cooled transformers and reactors . 39
7.2.4 AC harmonic filter and reactive power compensation equipment
capability . 40
7.2.5 Switchgear and buswork capability . 40
8 Minimum power transfer and no-load stand-by state . 40
8.1 General . 40
8.2 Minimum current . 40
8.3 Reduced direct voltage operation . 40
8.4 No-load stand-by state . 41
8.4.1 General . 41
8.4.2 Converter transformers – No-load stand-by . 41
8.4.3 Converter valves – No-load stand-by . 41
8.4.4 AC filters and reactive compensation – No-load stand-by . 41
8.4.5 DC reactors and DC filters – No-load stand-by . 42

8.4.6 Auxiliary power system – No-load stand-by . 42
8.4.7 Control and protection – No-load stand-by . 42
9 AC system . 42
9.1 General . 42
9.2 AC voltage . 42
9.2.1 Rated AC voltage . 42
9.2.2 Steady-state voltage range . 42
9.2.3 Negative sequence voltage . 43
9.3 Frequency . 43
9.3.1 Rated frequency . 43
9.3.2 Steady-state frequency range . 43
9.3.3 Short-term frequency variation . 43
9.3.4 Frequency variation during emergency . 44
9.4 System impedance at fundamental frequency . 44
9.5 System impedance at harmonic frequencies . 44
9.6 Positive and zero-sequence surge impedance. 44
9.7 Other sources of harmonics . 44
9.8 Subsynchronous torsional interaction (SSTI) . 44
10 Reactive power . 45
10.1 General . 45
10.2 Conventional HVDC systems . 45
10.3 Series capacitor compensated HVDC schemes . 47
10.4 Converter reactive power consumption . 47
10.5 Reactive power balance with the AC system . 47
10.6 Reactive power supply . 47
10.7 Maximum size of switchable VAR banks . 48
11 HVDC transmission line, earth electrode line and earth electrode . 48
11.1 General . 48
11.2 Overhead line(s) . 48
11.2.1 General . 48
11.2.2 Electrical parameters . 48
11.3 Cable line(s) . 49
11.3.1 General . 49
11.3.2 Electrical parameters . 49
11.4 Earth electrode line . 50
11.5 Earth electrode . 50
12 Reliability . 50
12.1 General . 50
12.2 Outage . 50
12.2.1 General . 50
12.2.2 Scheduled outage . 50
12.2.3 Forced outage . 50
12.3 Capacity . 51
12.3.1 General . 51
12.3.2 Maximum continuous capacity P . 51
m
12.3.3 Outage capacity P . 51
o
12.3.4 Outage derating factor (ODF) . 51
12.4 Outage duration terms . 51

– 4 – IEC TR 60919-1:2020 RLV © 2020
12.4.1 Actual outage duration (AOD) . 51
12.4.2 Equivalent outage duration (EOD) . 51
12.4.3 Period hours (PH) .
...