A Novel Islanding Detection Technique For Grid Connected High Pentrated Photovoltaic Systems

摘要

The increase in penetration of distributed generators (DG’s) connected to the grid, increases the efficiency of the grid, but at the same time brings new challenges. One such challenge is islanding, it is a critical and a hazardous condition in a power system, it occurs when a part of power system gets disconnected from the electric grid due to the grid outage, but that isolated part of the power system still remains energized by the local DG’s like photovoltaic (PV) system or so. The main disadvantage of islanding is that the utility staff working on-site in the islanded section may be prone to fatal accidents as they work on the live section without having knowledge of it, also there is a chance of damage to customer equipments, islanding may avoid automatic re-closure of devices to the grid after the fault is cleared. Hence, detection of islanding is a serious matter of concern. Islanding detection methods are classified as active, passive and hybrid methods. In this paper a novel islanding detection method using wavelet transformation (WT) for a grid connected high penetrated photovoltaic (PV) system is presented. This novel technique disconnects the islanded PV inverter from the system within 20ms, also ceases its operation as per IEEE-1547 and the THD of the grid voltage, grid current is less than 5% which is also as per the standards. The effectiveness of the proposed technique is validated by simulation using MATLAB/SIMULINK. The simulation results authenticate the proposed technique competence.