Complexity of ferroresonance phenomena: sensitivity studies from a single-phase system to three-phase reality

This paper contains a comprehensive literature review on ‘real case’ ferroresonance phenomena having occurred at different voltage levels of power systems. Sensitivity studies on a single phase system are conducted to understand the coupled effect of circuit breaker?s grading capacitor and circuit ground capacitor on the sustainability of ferroresonance. This coupling effect has been verified by test results obtained on a three phase 132/33 kV distribution system. ATPDraw simulation was performed to determine the correct values of grading and ground capacitances which then produce comparable simulation results to the field test recordings in terms of 3-phase voltages and currents measured from the two de-energisation tests. The complexity of ferroresonance issue is dominated by the nonlinearity of core, however circuit parameters, especially the “mix and match” of series capacitor and ground capacitor values also plays an importance role.