IEC TR 60919-3:2009

IEC TR 60919-3 ®
Edition 2.1 2016-03
CONSOLIDATED VERSION
TECHNICAL
REPORT
colour
inside
Performance of high-voltage direct current (HVDC) systems with line-
commutated converters –
Part 3: Dynamic conditions
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IEC TR 60919-3 ®
Edition 2.1 2016-03
CONSOLIDATED VERSION
TECHNICAL
REPORT
colour
inside
Performance of high-voltage direct current (HVDC) systems with line-

commutated converters –
Part 3: Dynamic conditions
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.200; 29.240.99 ISBN 978-2-8322-3241-5

IEC TR 60919-3 ®
Edition 2.1 2016-03
CONSOLIDATED VERSION
REDLINE VERSION
colour
inside
Performance of high-voltage direct current (HVDC) systems with line-
commutated converters –
Part 3: Dynamic conditions
– 2 – IEC TR 60919-3:2009+AMD1:2016 CSV
 IEC 2016
CONTENTS
FOREWORD. 5
1 Scope . 7
2 Normative references . 7
3 Outline of HVDC dynamic performance specifications . 8
3.1 Dynamic performance specification . 8
3.2 General comments . 9
4 AC system power flow and frequency control . 9
4.1 General . 9
4.2 Power flow control . 9
4.2.1 Steady-state power control requirements . 9
4.2.2 Step change power requirement . 10
4.3 Frequency control . 12
5 AC dynamic voltage control and interaction with reactive power sources . 13
5.1 General . 13
5.2 Voltage and reactive power characteristics of an HVDC substation and other
reactive power sources . 13
5.2.1 General . 13
5.2.2 Converter as active/reactive power source . 14
5.2.3 Voltage characteristics of a.c. networks depending on the power
loading at the busbar of the HVDC substation . 16
5.2.4 Voltage characteristics of a.c. filters, capacitor banks and shunt
reactors for power compensation at the HVDC substation . 18
5.2.5 Voltage characteristics of static var compensator (SVC) . 18
5.2.6 Voltage characteristics of synchronous compensator (SC) . 19
5.2.7 Voltage characteristics of static synchronous compensator
(STATCOM) . 19
5.3 Voltage deviations on the busbar of an HVDC substation . 19
5.4 Voltage and reactive power interaction of the substation and other reactive
power sources . 20
5.4.1 HVDC converters, switchable a.c. filters, capacitor banks and shunt
reactors . 20
5.4.2 HVDC converters, switchable reactive power sources, SVC . 21
5.4.3 HVDC converters, switchable reactive power sources and
synchronous compensators . 21
5.4.4 HVDC converters, switchable reactive power sources, STATCOM . 22
6 AC system transient and steady-state stability . 23
6.1 General . 23
6.2 Characteristics of active and reactive power modulation . 23
6.2.1 General . 23
6.2.2 Large signal modulation . 24
6.2.3 Small signal modulation . 25
6.2.4 Reactive power modulation . 25
6.3 Classification of network situations . 26
6.4 AC network in parallel with the HVDC link . 26
6.5 Improvement of the stability within one of the connected a.c. networks . 30
6.6 Determination of the damping control characteristics . 30

 IEC 2016
6.7 Implementation of the damping controller and telecommunication
requirements . 31
7 Dynamics of the HVDC system at higher frequencies . 31
7.1 General . 31
7.2 Types of instability . 32
7.2.1 Loop instability (harmonic instability) . 32
7.2.2 Current loop instability . 32
7.2.3 Core saturation instability . 32
7.2.4 Harmonic interactions . 32
7.3 Information required for design purposes . 33
7.4 Means available for preventing instabilities . 34
7.5 Damping of low order harmonics by control action . 34
7.6 Demonstration of satisfactory performance at higher frequencies . 34
8 Subsynchronous oscillations . 35
8.1 General . 35
8.2 Criteria for subsynchronous torsional interaction with an HVDC system . 36
8.3 Screening criteria for identifying generator units susceptible to torsional
interactions . 37
8.4 Performance considerations for utilizing subsynchronous damping controls
controllers (SSDCs) . 38
8.5 Performance testing . 38
8.6 Turbine generator protection . 38
9 Power plant interaction . 39
9.1 General . 39
9.2 Specific interactions . 39
9.2.1 General . 39
9.2.2 Frequency variation effects . 39
9.2.3 Frequency controls interactions . 40
9.2.4 Overvoltage effects . 40
9.2.5 Harmonics . 40
9.2.6 Subsynchronous and shaft impact effects . 40
9.2.7 Resonance . 41
9.2.8 Overvoltages . 41
9.2.9 Stresses in a.c. switching equipment . 41
9.2.10 Under-frequency . 41
9.2.11 Starting procedure for an HVDC converter . 41
9.3 Special considerations for a nuclear plant . 41
Bibliography . 42

Figure 1 – Elements for reactive power compensation at an HVDC substation . 14
Figure 2 – P/Q diagram of a converter . 15
Figure 3 – Reactive power requirements of a weak a.c. system depending on the active
power loading for various constant voltage characteristics at the a.c. bus of an HVDC
substation . 17
Figure 4 – Representation of the a.c. network . 17
Figure 5 – Example of voltage – current characteristic showing possible current
modulation range in the absence of telecommunication between rectifier and inverter . 25
Figure 6 – Reactive power modulation in an HVDC transmission operating at minimum
extinction angle γ . 27
min
– 4 – IEC TR 60919-3:2009+AMD1:2016 CSV
 IEC 2016
Figure 7 – Reactive power modulation in an HVDC transmission operating at extinction
angle γ > γ . 28
min
Figure 8 – Stability improvement of an a.c. link or network . 29
Figure 9 – Principle arrangements of a damping controller . 29

----------------------
...

IEC/TR 60919-3 ®
Edition 2.0 2009-10
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
Performance of high-voltage direct current (HVDC) systems with line-
commutated converters –
Part 3: Dynamic conditions
Fonctionnement des systèmes à courant continu haute tension (CCHT) munis
de convertisseurs commutés par le réseau –
Partie 3: Conditions dynamiques

IEC/TR 60919-3:2009
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by
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IEC/TR 60919-3 ®
Edition 2.0 2009-10
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
Performance of high-voltage direct current (HVDC) systems with line-
commutated converters –
Part 3: Dynamic conditions
Fonctionnement des systèmes à courant continu haute tension (CCHT) munis
de convertisseurs commutés par le réseau –
Partie 3: Conditions dynamiques

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
X
CODE PRIX
ICS 29.200; 29.240.99 ISBN 978-2-88910-332-4
– 2 – TR 60919-3 © IEC:2009
CONTENTS
FOREWORD.4
1 Scope.6
2 Normative references .6
3 Outline of HVDC dynamic performance specifications.7
3.1 Dynamic performance specification .7
3.2 General comments .8
4 AC system power flow and frequency control.8
4.1 General .8
4.2 Power flow control.8
4.2.1 Steady-state power control requirements.8
4.2.2 Step change power requirement .9
4.3 Frequency control .11
5 AC dynamic voltage control and interaction with reactive power sources .12
5.1 General .12
5.2 Voltage and reactive power characteristics of an HVDC substation and other
reactive power sources.12
5.2.1 General .12
5.2.2 Converter as active/reactive power source .13
5.2.3 Voltage characteristics of a.c. networks depending on the power
loading at the busbar of the HVDC substation.15
5.2.4 Voltage characteristics of a.c. filters, capacitor banks and shunt
reactors for power compensation at the HVDC substation.17
5.2.5 Voltage characteristics of static var compensator (SVC) .17
5.2.6 Voltage characteristics of synchronous compensator (SC).18
5.3 Voltage deviations on the busbar of an HVDC substation .18
5.4 Voltage and reactive power interaction of the substation and other reactive
power sources.19
5.4.1 HVDC converters, switchable a.c. filters, capacitor banks and shunt
reactors .19
5.4.2 HVDC converters, switchable reactive power sources, SVC.20
5.4.3 HVDC converters, switchable reactive power sources and
synchronous compensators .20
6 AC system transient and steady-state stability.21
6.1 General .21
6.2 Characteristics of active and reactive power modulation.21
6.2.1 General .21
6.2.2 Large signal modulation.22
6.2.3 Small signal modulation.23
6.2.4 Reactive power modulation.23
6.3 Classification of network situations.24
6.4 AC network in parallel with the HVDC link .24
6.5 Improvement of the stability within one of the connected a.c. networks .28
6.6 Determination of the damping control characteristics.28
6.7 Implementation of the damping controller and telecommunication
requirements .29
7 Dynamics of the HVDC system at higher frequencies .29
7.1 General .29
7.2 Types of instability .30

TR 60919-3 © IEC:2009 – 3 –
7.2.1 Loop instability (harmonic instability) .30
7.2.2 Current loop instability.30
7.2.3 Core saturation instability .30
7.2.4 Harmonic interactions.30
7.3 Information required for design purposes .31
7.4 Means available for preventing instabilities .32
7.5 Damping of low order harmonics by control action.32
7.6 Demonstration of satisfactory performance at higher frequencies .32
8 Subsynchronous oscillations.33
8.1 General .33
8.2 Criteria for subsynchronous torsional interaction with an HVDC system.34
8.3 Screening criteria for identifying generator units susceptible to torsional
interactions .35
8.4 Performance considerations for utilizing subsynchronous damping controls .36
8.5 Performance testing .36
8.6 Turbine generator protection .36
9 Power plant interaction .37
9.1 General .37
9.2 Specific interactions .37
9.2.1 General .37
9.2.2 Frequency variation effects.37
9.2.3 Frequency controls interactions .37
9.2.4 Overvoltage effects .38
9.2.5 Harmonics .38
9.2.6 Subsynchronous and shaft impact effects .38
9.2.7 Resonance .39
9.2.8 Overvoltages .39
9.2.9 Stresses in a.c. switching equipment .39
9.2.10 Under-frequency.39
9.2.11 Starting procedure for an HVDC converter.39
9.3 Special considerations for a nuclear plant .39
Bibliography.40

Figure 1 – Elements for reactive power compensation at an HVDC substation .13
Figure 2 – P/Q diagram of a converter .14
Figure 3 – Reactive power requirements of a weak a.c. system depending on the active
power loading for various constant voltage characteristics at the a.c. bus of an HVDC
substation .
...