Islanding Modelling and Detection for a Grid Connected Renewable Energy System

Abstract

Islanding is one of the issues that are related to grid – connected photovoltaic systems that affects the voltage and frequency of the system. Islanding is defined as the situation in which a distribution system becomes electrically isolated from the remaining power system and continues to be energized by the distributed generation resources. This study presents a method of detecting islanding phenomena in a distribution system equipped with renewable energy resources. The modeling of islanding phenomena was designed and simulated using MATLAB Simulink to extract the three–phase voltage signals at the common coupling point. Discrete Fast Fourier Transform and wavelet analysis techniques are used in this study to analyze the voltage on the loads to detect Islanding occurrence. Comparing between the results of both techniques show the effectiveness of Wavelet analysis over Discrete Fourier transform for different levels of loading. The fast response of wavelet analysis in Islanding detection can be added as a part of relay algorithm. The result will be helpful in development protection system design for a robust, fast response and effective protection system equipped with renewable energy sources.