IEC TR 62001-4:2021

IEC TR 62001-4 ®
Edition 2.0 2021-09
REDLINE VERSION
TECHNICAL
REPORT
colour
inside
High-voltage direct current (HVDC) systems – Guidance to the specification and
design evaluation of AC filters –
Part 4: Equipment
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IEC TR 62001-4 ®
Edition 2.0 2021-09
REDLINE VERSION
TECHNICAL
REPORT
colour
inside
High-voltage direct current (HVDC) systems – Guidance to the specification and
design evaluation of AC filters –
Part 4: Equipment
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.200 ISBN 978-2-8322-4531-6

– 2 – IEC TR 62001-4:2021 RLV © IEC 2021
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references. 9
3 Terms and definitions . 9
4 Steady state rating . 9
4.1 General . 9
4.2 Calculation method . 10
4.2.1 General . 10
4.2.2 AC system pre-existing harmonics . 11
4.2.3 Combination of converter and pre-existing harmonics . 12
4.2.4 Equipment rating calculations . 12
4.2.5 Application of voltage ratings. 16
4.3 AC network conditions . 17
4.4 De-tuning effects . 17
4.5 Network impedance for rating calculations . 17
4.6 Outages . 18
5 Transient stresses and rating . 18
5.1 General . 18
5.2 Switching impulse studies . 19
5.2.1 Energization and switching . 19
5.2.2 Faults external to the filter . 21
5.2.3 Faults internal to the filter . 22
5.2.4 Transformer inrush currents . 23
5.3 Fast fronted waveform studies . 23
5.3.1 General . 23
5.3.2 Lightning strikes . 23
5.3.3 Busbar flashover studies . 23
5.4 Insulation co-ordination . 23
6 Losses . 25
6.1 Background . 25
6.2 AC filter component losses . 25
6.2.1 General . 25
6.2.2 Filter/shunt capacitor losses . 26
6.3 Reactor and resistor losses . 27
6.3.1 General . 27
6.3.2 Filter resistor losses . 28
6.3.3 Shunt reactor losses . 28
6.4 Criteria for loss evaluation . 28
6.4.1 General . 28
6.4.2 Fundamental frequency AC filter busbar voltage . 29
6.4.3 Fundamental frequency and ambient temperature . 29
6.4.4 AC system harmonic impedance . 29
6.4.5 Harmonic currents generated by the converter . 30
6.4.6 Pre-existing harmonic distortion . 30
6.4.7 Anticipated load profile of the converter station . 31

7 Design issues and special applications . 31
7.1 General . 31
7.2 Performance aspects . 31
7.2.1 Low order harmonic filtering and resonance conditions with AC system . 31
7.2.2 Definition of interference factors to include harmonics up to 5 kHz . 32
7.2.3 Triple-tuned filter circuits . 33
7.2.4 Harmonic AC filters on tertiary winding of converter transformers . 34
7.3 Rating aspects . 35
7.3.1 Limiting high harmonic currents in parallel-resonant filter circuits . 35
7.3.2 Transient ratings of parallel circuits in multiple tuned filters . 35
7.3.3 Overload protection of high-pass harmonic filter resistors . 36
7.3.4 Back-to-back switching of filters or shunt capacitors . 36
7.3.5 Short time overload – reasonable specification of requirements . 36
7.3.6 Low voltage filter capacitors without fuses . 37
7.4 Filters for special purposes . 38
7.4.1 Harmonic filters for damping transient overvoltages . 38
7.4.2 Non-linear filters for low order harmonics/transient overvoltages . 38
7.4.3 Series filters for HVDC converter stations . 39
7.4.4 Re-tunable AC filters . 42
7.5 Impact of new HVDC station in vicinity of an existing station . 43
7.6 Redundancy issues and spares . 44
7.6.1 Redundancy of filters – Savings in ratings and losses . 44
7.6.2 Internal filter redundancy . 45
7.6.3 Spare parts . 45
8 Protection . 46
8.1 Overview. 46
8.2 General . 46
8.3 Bank and sub-bank overall protection . 48
8.3.1 General . 48
8.3.2 Short-circuit protection . 48
8.3.3 Overcurrent protection . 48
8.3.4 Thermal overload protection . 48
8.3.5 Differential protection . 49
8.3.6 Earth fault protection . 49
8.3.7 Overvoltage and undervoltage protection . 49
8.3.8 Special protection functions and harmonic measurements . 50
8.3.9 Busbar and breaker failure protection . 50
8.4 Protection of individual filter components . 50
8.4.1 Unbalance protection for filter and shunt capacitors . 50
8.4.2 Protection of low voltage tuning capacitors . 52
8.4.3 Overload protection and detection of filter detuning . 52
8.4.4 Temperature measurement for protection . 52
8.4.5 Measurement of fundamental frequency components . 52
8.4.6 Capacitor fuses . 53
8.4.7 Protection and rating of instrument transformers . 53
8.4.8 Examples of protection arrangements . 54
8.5 Personnel protection . 54
9 Audible noise . 57
9.1 General . 57

– 4 – IEC TR 62001-4:2021 RLV © IEC 2021
9.2 Sound active components of AC filters . 57
9.3 Sound requirements . 59
9.4 Noise reduction . 59
10 Seismic requirements . 60
10.1 General .
...