Detection of islanding conditions in distribution network with penetration of DGs based on wavelet analysis

This paper presents a new fast and reliable method for islanding detection based on measuring the utility current signal processed by discrete wavelet transform. This signal is measured before the main circuit breaker and its feature extracted by discrete wavelet transform. This feature is wavelet coefficient energy and distinguishes the islanding conditions from non-islanding ones. Because of changing in measuring point of current signal from point of common coupling in traditional methods to before the main circuit breaker in proposed method, and using its transient data, this new method detects the islanding conditions faster than the other methods. The proposed method is useful for islanding detection in the networks with multiple distributed generations. To confirm the accuracy of this method, the method has been validated through several scenarios. Simulation results supported the robustness of the proposed method for the application considered.