Analysis of ferroresonance in a 20kV distribution network

Ferroresonance has more damaging effects on transformers and other equipments in distribution networks such as oscillating over voltages and over currents, distortion in voltage and current waveforms, transformer heating, loud noise due to magnetostriction and mal-operation of the protective devices. In this paper the factors that affect the ferroresonance over-voltages are checked to find the method that can mitigate the overvoltages in the 20 kV distribution system. The main factors mainly include; energization and deenergization phase angle, loads of transformer, multi-transformers in parallel, single-phase and multi-phase switching operation, line capacitance, connection of transformer primary winding and switching time duration. The purposed solutions of this problem are determined on the simulation results.