Influence of winding short circuits on the transfer function of power transformer windings by example of homogeneous coils

The analysis of transfer functions, calculated e.g. from exciting voltage and current to ground, is a method for monitoring of power transformers in service. Especially for the detection of mechanical changes in the winding assembly, the transfer function method is in discussion. A second application field is the evaluation of the impulse test of power transformers in the test laboratory. However, up to now, there exists nearly no knowledge about the relationship between nature and location of an internal fault and its effect on the transfer function. In this paper the influence of the location of short circuits in the winding on the waveform of the transfer function is examined at the example of homogeneous coils by comparing measurements and calculations.