Islanding Detection Method Based On Energy Wavelet In Distribution System Embedded With Distributed Generation

In this paper, a new passive method of islanding detection is proposed based on energy of wavelet coefficients in Distributed Generation (DG) systems. This new method is developed for islanding detection based on measuring the utility voltage signals. These voltage signals are measured before the main circuit breaker of micro grid including wind turbine DFIG, diesel generator, battery and different loads. Signal’s features are processed and extracted by Discrete Wavelet Transform (DWT) and adequate decomposition level. This method detects the islanding condition with the Daubiches wavelets. Voltage signals are sampled at 20 KHZ. Features and wavelet coefficients are achieved from mean voltage of three phases and these parameters are used for distinguishing the islanding conditions from non-islanding ones. The proposed method has been examined under various scenarios including one phase fault, three phases fault, capacitor switching, load shedding and load injecting. The numerical studies show that feasibility and applicability of the proposed method with acceptable and satisfactory results. The results show that the proposed islanding detection method is able to detect islanding operation very fast in an efficient way. Matlab/Simulink software is employed for this purpose.