TRANSFORMER INTERNAL FAILURE DETECTION BY FREQUENCY RESPONSE ANALYSIS (FRA)

Abstract

Detection of internal failures in the power transformers is the major issue as these factors are much needed for the power system as far the reliability is concerned and also the replacement cost of these components is more. Mainly the internal faults occur due to winding deformation, buckling of conductors, winding displacements, stretching of conductors and these may cause the transformer failure. Thus the monitoring of the transformer condition is necessary. Although, there are many methods presented for detection of internal failures in the transformer, but frequency-response analysis (FRA) has gained great interest due to its sensitivity to failures in the windings. These failures can be detected by evaluating transfer function changes. The new methodology is based on decomposition of signals to obtain smoothed response for comparison; it gives robustness to the process by defining type of internal fault on winding