Wavelet-based Islanding Detection in Grid-Connected PV Systems

Abstract

Distributed Power Generation Systems (DPGS) based on inverters require reliable islanding detection algorithms (passive or active) in order to determine the electrical grid status and operate the grid connected inverter properly. These methods are based on the analysis of the DPGS voltage, current and power in time or frequency domain. This paper proposes a time-frequency detection algorithm based on monitoring the DPGS output power considering the influence of the PWM, the output LCL filter and of the employed current controller. Wavelet analysis is applied to obtain time localization of the islanding condition. Simulation and experimental results show the performance of the proposed detection algorithm also in comparison with existing methods.