Mains harmonics in supply systems other than 230/400 V 50 Hz

By J. M. Woodgate B.Sc.(Eng.) C.Eng.  MIET SMIEEE FAES Hon FInstSCE MIOA

Mains harmonics in supply systems other than 230/400 V 50 Hz

We have IEC 61000-3-2 and -12 (and the Technical Report IEC TR 61000-3-4), but these only apply to 230/400 V (or similar) 50 Hz systems. They have ben adapted/adapted by some countries outside Europe and Japan has extensively modified 61000-3-2 for their 100 V 50 Hz and 60 Hz systems. Attempts were made in IEEE to produce a standard for the Americas, or at least North America, but it did not receive sufficient support.

The fundamental (!) cause is that some Canadian distribution system operators (DSOs) have serious trouble with the effects of harmonics on their extremely long medium voltage (MV) feeders, while the majority of US DSOs do not have much trouble with harmonics. They have a site-level standard IEEE 519 which applies to industrial sites, but nothing at household level because the system feeds only a few dwellings at low-voltage (LV) from a single MV:LV transformer. But they have many troubles with their often outdated systems, and a shortage of inter-state high-power distribution lines, so harmonic limitation is not a priority.

The Canadian National Committee approached IEC SC77A with a proposal, which has been somewhat modified, to begin with a world-wide survey and data collection for all AC distribution systems. This is intended to be published as a Technical Report in the IEC 61000-1 series.  Advanced statistical methods are being used to analyse the limited amount of data so far received. of course, these data relate to system-level power quality issues, so do not relate directly to emission limits at load equipment level.