An integrated passive islanding detection method for grid connected PV distributed generators

Abstract

This study proposes an islanding detection method for use with gridinterconnected distributed generators (DGs). The method is based on two indices; the rate of change of frequency (ROCOF) and the rate of change of voltage (ROCOV). When a DG is connected to grid, the ROCOF and ROCOV are lower than the threshold value. In contrast, as an islanding occurs, the ROCOF or ROCOV become much higher than the threshold values. Detection systems monitor terminal voltage at the grid-interconnected point to calculate ROCOF and ROCOV, and issue an operating signal when the value and exceed a given threshold. In this study, simulations are performed to illustrate the principles of the proposed technique for grid connected photo-voltaic (PV) generator. The test results show that the proposed method is reliable, economical, and easy to implement for islanding detection of distributed generators. Islanding detection methods are investigated, simulated and evaluated using MATLAB /SIMULINK package.