This part of IEC 62001, which is a Technical Report, provides guidance on the performance aspects and verification of performance of harmonic filters. 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.