Wavelet approach to power quality monitoring

Power quality issues have become more concerned with the extensive use of power electronic devices and nonlinear loads in the electric power system, the sensitive detection and accurate classification of power disturbances attracts more attention from both utilities and industrial customers. A wavelet transform based new approach to the detection of power disturbance and measurement of power quality is proposed in this paper. This approach adopts a series of complex wavelet functions as multi-channel band pass FIR filters to detect the occurrence of disturbance, and precisely estimate the instantaneous average magnitudes and frequencies in their respective frequency bands as time varies, which are essential to power quality assessment. The performance evaluation of the proposed approach has been conducted under a variety of disturbances including momentary interruption, sag, swell, flicker, harmonics, frequency deviation, transients etc., on the basis of simulations in MATLAB environment. The evaluation results demonstrate the effectiveness and advantages of the proposed approach