A Passive Islanding Detection Technique for Grid connected Solar Photovoltaic System

Abstract

The world is moving progressively towards the power generation from renewable energy resources because these are inexhaustible, pollution free and available richly in the nature. Due to the advantages of renewable power generation, the grid interconnection of distributed generator (DG) is growing in the power market. The major drawback of this interconnection is an unintentional islanding. The islanding takes place in the power system when the distributed generator continues supply power even when the grid is not connected to the system. However, an unintentional islanding is an unplanned islanding which is harmful to the power system and the people working in it. Therefore it is essential to detect an unintentional islanding so to prevent from its harmful consequences. The islanding must be detected within minimum time delay i.e. within a 2 sec. as per the IEEE standard. In this paper, a solar photovoltaic DG is integrated with the main grid. A total harmonic distortion (THD) based passive method is employed here to detect the islanding in a grid tied solar PV system. In this method, changes in level of harmonics are observed in local parameters based on which detects the islanding. This method has reduced non-detection zone over other passive methods.