Wavelet transform based protection of stator faults in synchronous generators

Abstract

This article presents a novel wavelet power based algorithm for protection of stator windings of a three-phase synchronous generator. The proposed algorithm is based on the comparison of the instantaneous power of the wavelet packet transform coefficients of voltage and current samples of different faulted and normal conditions acquired from the terminals of the generator. The wavelet powers of the second level high frequency details of fault currents and voltages using a selected mother wavelet show distinctive features between different faulted and normal conditions. The proposed wavelet power based detection algorithm is developed and implemented in real-time using the ds1102 digital signal processor board. The protection technique is tested on-line on a laboratory 1.6 kW three-phase synchronous generator. Different types of stator faults at generator terminals for testing the technique in real-time, faults were identified promptly and properly, and the trip signal was initiated almost at the instant or within one cycle of fault occurrence.