Mitigating ferroresonance in MV power system involving power transformer and circuit breaker capacitance using alternating transient program

Abstract

Ferroresonance is a phenomenon usually initiated by transients in power networks resulting from switching operations or ground faults or others. Nonlinear behavior of the core of a power transformer results in magnetic saturation. Long-lasting ferroresonant state is dangerous to the equipment due to prolonged overvoltage and large overcurrents in MV windings. In this thesis, a ferroresonance solution using Alternating Transient Program, was attempted. The ferroresonant oscillations analyzed result from interaction between the power transformer and a grading capacitance of a circuit breaker. Some practical solutions are suggested and introduced after creating a ferroresonance situation, they had a considerable effect on damping and eliminating the risk of ferroresonance.