A wavelet-based approach for protection of generators against unbalanced currents

Abstract

This paper presents a new wavelet-based negative-phase sequence (unbalanced currents) protection scheme for synchronous generators. The scheme utilizes the three line voltages and the three line currents available at the generator terminals. Wavelet transform concept is presented. The principle of operation of the algorithm is introduced. Feature extraction technique is derived. Data window necessary for the algorithm is ten samples based on 1200 Hz sampling frequency. Generated data from the simulation of a model power system using EMTP were used in the MATLAB software to test the performance of the technique. The performance under different system conditions is discussed. The results show that the new approach provides robust and accurate classification for a variety of power system conditions. (C) 2002 Elsevier Science B.V. All rights reserved