Controlling ferroresonance oscillations in potential transformer: Part I

Ferroresonance overvoltage is an unwanted electrical phenomenon, which may cause over voltages and over currents in the electrical power. This paper studies the effect of circuit breaker shunt resistance, and Metal Oxide Surge Arrester (MOSA) on the control of chaotic ferroresonance in a Potential transformer (PT). It is expected that this resistance, and MOSA generally can cause ferroresonance `dropout´. For confirmation this phenomenon, simulation is investigated on a one phase potential transformer rated 100 VA, 275 kV. Simulation results reveal that considering shunt resistance on the circuit breaker and MOSA in parallel with potential transformer exhibits a great mitigating effect of ferroresonance over voltages. Significant effect on the onset of ferroresonance, the range of parameter values that may cause to chaotic ferroresonance is obtained and presented.