Dynamic Overvoltages and Ferroresonance Found in Switching Surge Studies for Iran 400 KV System

This paper describes the most significant results of a study performed for the 400 kV Reza Shah Kabir (RSK) hydroelectric project in Iran. Emphasis is placed on dynamic overvoltages and ferroresonance caused by saturation of the generator transformer. The effect of changes in generator and transformer reactances on ferroresonance is presented and discussed. Closing, reclosing and fault clearing overvoltages together with the transients following load rejection are described. The possibility of using single phase reclosing is discussed.