Evaluation of Transformer Faults Using Double Fourier Series – a Fastest Method for Field Computations

Transformers are essential and important elements of power systems. In the past few years, there has been an increasing concern about the occurrence of turn-to-turn faults in power transformers due to the high costs that unexpected outages cause. It is not always possible to analyze the transformer behavior under such faults under rated conditions, since the tests are largely destructive. Therefore, in order to avoid severe damage to machines, models are used for the analysis. Thus, many attempts were made to develop a more accurate method to compute the fault currents, among which Finite Element Method (FEM)-based approaches are the most accurate. Unfortunately, the time taken to model and solve by such methods is more, especially when the number of elements considered are more. This tempts the designer to think of an accurate and quickest method of evaluation of fault currents. One such method is presented in this article. Here, a field-based method is proposed for the analysis of internal winding faults of a Power transformer. The transformer with turn-to-turn fault is modeled using an analytical method based on the concept of “Application of Double Fourier Series for irregular flux distribution” [1]. The normal and various faulty cases are presented, which will help in the study of the terminal behavior of the transformer.