Insulation fault monitoring of power transformer by transfer function method

A transfer function method is being developed for both the impulse test and monitoring of power transformers. A three-phase equivalent circuit of power transformer based on the Bergeron method is created in this paper. The influences of input signals with different frequency characteristics on transfer function calculation are analyzed and a suitable input is selected to perform the evaluation of transformers' insulation conditions by transfer function method. Three different types of transformer faults are simulated in this paper. The results show the potential contributions to insulation fault monitoring and location.