Islanding disclosure for grid interactive PV-VSC system using negative sequence voltage

This paper presents a new study on active islanding detection method for grid connected photovoltaic (PV) based voltage source converter (VSC) system. The VSC system is basically controlled by positive sequence P-Q loop, where point of common coupling (PCC) power components are measured parameters. But during grid disconnection an islanding detection loop is further implemented with existing control, based on negative sequence voltage ( neg dq V , ) at PCC. The threshold for the feedback sequence voltage is determined to maintain a negligible non detection zone (NDZ) and to avoid false detection during other power quality issues. Worst case scenario is considered by implementing a PV based VSC system from IEEE UL 1741 standard. Performance of the proposed islanding detection loop is investigated in MATLAB/ Simulink environment. The efficient detection of islanding with less than a cycle Run on time is ensured by the result analysis, where no significant effect in power quality during normal operating condition has been maintained.