Transient overvoltage response performance of transformer windings with short‐circuit fault

Abstract

The fault diagnosis of transformer windings is a basis for condition maintenance. Conventional online or offline diagnosis methods require additional pulse or impulse signal. If the overvoltage signal can be regarded as the broadband excitation source for the fault diagnosis of transformer windings, the interference caused by signal injection is likely eliminated without additional pulse or impulse signals. In this study, the transient overvoltage response performance of transformer windings with short-circuit fault is presented, which could provide a new method for the diagnosis on transformer fault diagnosis. A 10 kVA, 2400 V/220 V, 50 Hz, 1-phase tapped transformer was designed, and a test platform for the fault diagnosis of transformer windings is established. The excitation signals for the fault diagnosis of the transformer windings included different lightning waves and damped oscillation waves, as indicated by the differences among actual overvoltage waveforms. The voltage and current of windings under normal and fault conditions are determined, and the frequency responses of admittance and voltage transfer function are calculated. The criterion for the fault diagnosis of transformer windings is obtained by comparing and analysing statistical indicators that reflected the differences in the frequency response of transfer function under normal and fault.