Systematic analysis of the harmonics in resonant grounding systems

This paper deals with the causes, propagation and resonance phenomena of harmonics in the zero sequence currents and line-to-earth voltages of medium voltage (MV) networks with grounding via Peterson coils. Of special interest is the relation of these harmonics between normal and earth fault operation of the network. The results of these works are basic of further investigations in the field of fault arc clearance behaviour. To evaluate the damping, resonance and propagation of harmonics in MV systems, a test network is modelled and simulated during normal operation conditions and during a single-phase fault. Numerical results obtained with ATP-EMTP are presented.