Overview
IEC TR 62001-4:2021 - High-voltage direct current (HVDC) systems: Guidance to the specification and design evaluation of AC filters - Part 4: Equipment - is a Technical Report from the IEC that gives practical guidance on the AC-side filter equipment used at HVDC converter stations. It covers basic data, ratings, power losses, design issues and special applications, protection, seismic requirements, and equipment design and test parameters for AC filters and their components (capacitors, reactors, resistors, arresters, instrument transformers, switching gear).
The report addresses harmonic distortion and audible-frequency disturbances of interest for HVDC systems (mainly conventional AC filter technology and LCC - line-commutated converter - HVDC), noting much of the guidance is applicable to VSC (voltage-sourced converter) systems. It excludes filters intended for power line carrier (PLC) or radio-interference spectra. Annex A from the previous edition was deleted and its content is now covered by IEC 61803.
Key topics and technical requirements
- Steady-state ratings - methods for calculating filter/component ratings considering converter and pre-existing AC system harmonics, network impedance, de-tuning and outage conditions.
- Transient stresses and insulation coordination - energisation, switching impulses, internal/external faults, fast-front waveforms, lightning and transformer inrush effects.
- Losses and thermal evaluation - component loss mechanisms, criteria for loss evaluation, ambient and loading considerations.
- Design issues & special applications - resonance and low-order harmonic filtering, triple-tuned filters, tertiary-winding filters, re-tunable filters, damping of transient overvoltages, redundancy and spare strategy.
- Protection - bank/sub-bank protection schemes, overcurrent, differential, earth-fault, thermal overload, unbalance and detuning detection, measurement functions and personnel protection.
- Audible noise & mechanical design - noise sources, measurement and mitigation.
- Seismic requirements - load specification, qualification by analysis, design criteria and documentation.
- Equipment design & tests - technical information for procurement, electrical/mechanical data and factory/site tests for capacitors, reactors, resistors, arresters, instrument transformers and switchgear.
Practical applications and users
This TR is essential for:
- HVDC converter station designers and electrical engineers specifying AC filters
- Utilities and system operators preparing technical specifications and tender documents
- Manufacturers of filter capacitors, reactors, resistors, arresters and switchgear
- Test laboratories and commissioning teams validating equipment ratings, losses, insulation coordination and seismic qualification
- Project managers and consultants assessing filter performance, reliability, and noise/environmental compliance
Related standards
- IEC TR 62001 (series) - overarching guidance for HVDC AC filters
- IEC 61803 - referenced for Annex A content (now covered there)
- Applicable IEC standards for capacitors, reactors, surge arresters and instrument transformers (consult TR 62001-4 for specific normative references)
Keywords: IEC TR 62001-4:2021, HVDC AC filters, harmonic filtering, LCC HVDC, VSC HVDC, filter design, capacitor/reactor/resistor tests, insulation coordination, seismic qualification.