An Efficient Passive Islanding Detection Method for Integrated DG System with Zero NDZ

Abstract

In this paper an efficient passive islanding detection scheme is presented for renewable distributed generation (DG). Islanding is caused if DG supplies power to load after disconnecting from the grid due to system failure or an act of nature. As per the DG interconnection standards, it is required to detect the islanding within 2 seconds after islanding with the equipments connected to it. In this paper, the islanding is detected with the combined changes of rate of change of positive sequence voltage (ROCOPSV) and rate of change of positive sequence current (ROCOPSC). The islanding is detected if both the values of ROCOPSV and ROCOPSC are more than a predefined threshold value. The test system results carried on MATLAB shows the performance of the proposed method for various islanding and non islanding events with different power imbalances. Various non islanding cases like capacitor switching, load swithching are also clearly differentiated with islanding events. Islanding detction is posible at balanced islanding with zero non detection zone (NDZ) by proposed technique.