Islanding and fault detection of inverter based distributed generations using wavelet packet transform and ensemble

Abstract

The adoption of Distributed Generation (DG) technology has seen a substantial level of advancement in recent years. This has created potential protection issues in microgrids during faults and islanding. This paper proposes a fault and islanding detection method using wavelet packet transform (WPT) and Ensemble. A new index called Normalized RMS Node power index (NRNPI) is defined based on WPT to differentiate between transient behavior during faults and islanding, and the ensemble acts as a classifier. The ability of the method in detecting islanding and both grounded and non-grounded faults is demonstrated through simulations of a test system in Matlab Simulink. Real time simulation of the proposed method is done in OPAL-RT using UDP-IP communication protocol. The proposed method as an islanding detection technique gives an accuracy of 100% and 99.32 % as a fault detection technique under the test conditions. Results of both simulations and Hardware in Loop (HIL) implementation is promising. The proposed method has the potential of extending the idea for other transient analysis in the microgrid.