Power Quality Disturbances Analysis using Two Forms of Wigner-Ville Distribution

Power quality (PQ) is a major concern to both power utilities and consumers due to the widespread use of sensitive loads, power electronic devices and industrial equipments. This paper presents an analysis of PQ disturbances as a first step of their appropriate identification using time-frequency analysis. The research focused on the two most common forms of PQ disturbances in Nigeria: voltage sag and swell. The disturbance analysis was based on two basic forms of Wigner-Ville distribution (WVD); the windowed WVD and the filtered WVD used in conjunction with Hilbert transform. Results obtained showed that both forms of WVD are able to accurately capture the disturbances with concentration of energy along the main power supply frequency of 50Hz within the PQ disturbance duration of 0.1s. The proposed methodology showed that the WVDs would be a good signal processing method for subsequent classification of PQ disturbances in electrical power smart grid.