A novel measurement technique for power transformer faults using spectral comparison technique

The paper proposes a new measurement technique for detecting transformer faults. A specially designed transient current detection device is used to capture the fault generated high frequency current transients. The device tuned to a special band of high frequency is connected to the transformer through the CTs at both high and low voltage sides of the transformer. The captured transient signals at both ends of the transformer are then compared, with particular emphasis on the high frequency characteristics in the frequency domain; the internal faults are discriminated from the external fault by spectral comparison. The high frequency modelling of the transformer is incorporated into the simulation. The simulation also involves the modelling of the faults between any turn and the earth and between any two turns of the transformer windings.