IEC TR 62001-3:2016

High-voltage direct current (HVDC) systems - Guidance to the specification and design evaluation of AC filters - Part 3: Modelling

IEC TR 62001-3:2016(E), which is a Technical Report, provides guidance on the harmonic interaction across converters, pre-existing harmonics, AC network impedance modelling and simulation of AC filter performance. The scope of this document covers AC side filtering for the frequency range of interest in terms of harmonic distortion and audible frequency disturbances. It excludes filters designed to be effective in the PLC and radio interference spectra. This document concerns the "conventional" AC filter technology and line-commutated high-voltage direct current (HVDC) converters. This first edition of IEC TR 62001-3, together with IEC TR 62001-1, IEC TR 62001-2 and IEC TR 62001-4, cancels and replaces IEC TR 62001 published in 2009. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to IEC TR 62001: a) expanded and supplemented Clause 6; b) new Clause 4; c) new Clause 5; d) new annexes on the location of worst case network impedance; e) accuracy of network component modelling at harmonic frequencies; f) further guidance for the measurement of harmonic voltage distortion; g) project experience of pre-existing harmonic issues; h) worked examples showing impact of pre-existing distortion; i) comparison of calculation methods.

General Information

• Status: Published
• Publication Date: 21-Sep-2016
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 29.200 - Rectifiers. Convertors. Stabilized power supply
• Technical Committee: SC 22F - Power electronics for electrical transmission and distribution systems
• Drafting Committee: MT 21 - TC 22/SC 22F/MT 21
• Current Stage: PPUB - Publication issued
• Start Date: 31-Dec-2016
• Completion Date: 22-Sep-2016

Relations

• Replaces: IEC TR 62001:2009 - High-voltage direct current (HVDC) systems - Guidebook to the specification and design evaluation of A.C. filters
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC TR 62001-3 ®
Edition 1.0 2016-09
TECHNICAL
REPORT
colour
inside
High-voltage direct current (HVDC) systems – Guidance to the specification and
design evaluation of AC filters –
Part 3: Modelling
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IEC TR 62001-3 ®
Edition 1.0 2016-09
TECHNICAL
REPORT
colour
inside
High-voltage direct current (HVDC) systems – Guidance to the specification and

design evaluation of AC filters –

Part 3: Modelling
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.200 ISBN 978-2-8322-3655-0

– 2 – IEC TR 62001-3:2016 © IEC 2016
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
2 Normative references. 10
3 Harmonic interaction across converters . 10
3.1 General . 10
3.2 Practical experience of problems . 11
3.3 Indicators of where harmonic interaction is significant . 13
3.4 Interaction phenomena . 14
3.5 Impact on AC filter design . 15
3.5.1 General . 15
3.5.2 AC side third harmonic . 15
3.5.3 Direct current on the AC side . 16
3.5.4 Characteristic harmonics . 16
3.6 General overview of modelling techniques . 16
3.6.1 General . 16
3.6.2 Time domain AC-DC-AC interaction model . 18
3.6.3 Frequency domain AC-DC-AC interaction model . 19
3.6.4 Frequency domain AC-DC interaction model . 19
3.6.5 Frequency domain current source model . 19
3.7 Interaction modelling . 20
3.7.1 General . 20
3.7.2 Coupling between networks . 20
3.7.3 Driving forces. 21
3.7.4 System harmonic impedances . 22
3.8 Study methods . 22
3.8.1 Frequency domain . 22
3.8.2 Time domain . 22
3.9 Composite resonance . 23
3.10 Core saturation instability . 23
3.11 Particular considerations for back-to-back converters . 23
3.12 Issues to be considered in the design process . 24
3.12.1 General . 24
3.12.2 Fundamental frequency and load issues . 24
3.12.3 Negative phase sequence . 25
3.12.4 Pre-existing harmonic distortion . 26
3.12.5 AC network impedance . 27
3.12.6 Converter control system . 28
3.12.7 Combination with "classic" harmonic generation . 29
3.12.8 Relative magnitude of pairs of low-order harmonics . 29
3.12.9 Superposition of contributions . 30
3.13 Parallel AC lines and converter transformer saturation . 30
3.14 Possible countermeasures . 32
3.14.1 AC (and/or DC) filters . 32
3.14.2 DC control design . 32
3.14.3 Operating restrictions and design protections . 33

3.15 Recommendations for technical specifications . 33
3.15.1 General . 33
3.15.2 Specified design data . 33
3.15.3 Requirements regarding calculation techniques . 34
4 AC network impedance modelling . 35
4.1 General . 35
4.2 Implications of inaccurate definition of network impedance . 36
4.3 Considerations for network modelling . 37
4.3.1 General . 37
4.3.2 Project life expectancy and robustness of data . 37
4.3.3 Network operating conditions . 37
4.3.4 Network impedances for performance and rating calculations . 38
4.3.5 Modelling of network components . 39
4.3.6 Representation of loads at harmonic frequencies . 40
4.4 Network harmonic impedance envelopes . 40
4.5 Methods of determining envelope characteristics . 43
4.5.1 General . 43
4.5.2 Low order harmonics . 43
4.5.3 Mid-range and higher order harmonics . 44
4.5.4 Balancing of risk and benefit . 45
4.5.5 Consideration of tolerances on harmonic bands . 46
4.5.6 Two separate envelopes for one harmonic band . 48
4.5.7 Critical envelope parameters . 49
4.5.8 Impedance envelopes for performance and rating conditions . 49
4.6 Examples of the impact of different network impedance representations . 50
4.6.1 Effect of network envelope parameters on resultant distortion . 50
4.6.2 Effect of network minimum resistance on filter rating . 53
4.7 Interharmonic impedance assessment . 54
4.8 Measurement of network harmonic impedance . 56
4.9 Conclusions . 57
5 Pre-existing harmonics . 57
5.1 General . 57
5.2 Modelling and measurement of pre-existing harmonic levels . 58
5.3 Harmonic performance evaluation, methods and discussion . 60
5.3.1 General . 60
5.3.2 "Incremental" harmonic performance evaluation . 60
5.3.3 "Aggregate" harmonic performance evaluation . 61
5.3.4 Both "incremental" and "aggregate" performance evaluation . 62
5.3.5 "Incremental" and "maximum magnification factor" harmonic
performance evaluation . 63
5.4 Calculation of total harmonic performance indices . 63
5.5 Harmonic rating evaluation . 64
5.6 Difficulties with the voltage source/worst network model for rating . 65
5.6.1 Background . 65
5.6.2 Illustration of the voltage source/worst network method . 66
5.7 Further possible calculation procedures for rating evaluation . 68
5.7.1 Using measured levels of pre-existing distortion . 68
5.7.2 Applying compatibility level voltage source at the filter busbar. 70

– 4 – IEC TR 62001-3:2016 © IEC 2016
5.7.3 Limiting the filter bus harmonic voltage to a maximum level for filter
rating (MLFR) . 72
5.7.4 Limiting total source distortion to the defined THD . 73
5.7.5 Limiting harmonic order of pre-existing distortion . 75
5.8 Conclusions . 75
Annex A (informative) Location of worst-case network impedance .
...