Simulation of Ferroresonance Occurring in Power System Containing voltage Transformer

Ferroresonance is a prolonged overvoltage condition that can damage transformers and other connected equipment. It can occur in the inductive voltage transformers as a result of the disconnecting of a busbar or a line section by opening circuit breakers equipped with grading capacitors. Ferroresonance creates highly distorted waveforms, which can cause abnormally high overvoltages. The level of overvoltages depends on the system parameters and the values of those parameters therefore need to be known. Such knowledge is possible either by means of practical experiments or by computer analyses. Due to the fact that it is not possible to do a lot of practical experiments in a real power system, the second possibility prevails. In this paper some outputs of analyses performed in the MATLAB and Simulink environment are shown and results are discussed.