Zero Sequence Harmonic Current Generation in Transmission Lines Connected to Large Convertor Plant

Although the bridge-type convertor produces only positive and negative sequence harmonic currents, the coupling between sequence networks resulting from ac transmission asymmetries can cause considerable zero sequence interference in nearby power or communications lines. This paper discusses the modelling of ac system and convertor plant components needed to assess the level of zero sequence harmonic current generation in transmission lines connected to large convertor plant.