Detection and characterization of voltage disturbances using wavelet transforms

This paper presents a new technique for detecting and characterizing disturbances in power systems based on wavelet transforms. The voltage signal under investigation is often corrupted by noises, therefore the signal is first de-noised and then wavelet transform is applied. Using the first detail wavelet coefficients, voltage disturbance is detected and its duration is determined. The voltage disturbance is classified using the approximation wavelet coefficients. To test developed scheme, diverse data obtained from MATLAB for different types of transient disturbances, voltage sags, voltage swells, short time interruptions, and voltage dips are employed. Simulation results show that the proposed method is fast and accurate. Furthermore, remarkable efficiency of monitoring the power quality problems and high tolerance to the noises are approved.