Analysis on non-detection zone of the islanding detection in photovoltaic grid-connected power system

Until now, there is a great development in photovoltaic grid-connected power system. In addition, there is an ongoing research on the problems existed in the system. Islanding of photovoltaic grid-connected power system have adverse impact on power quality and utility equipments, affecting the performance of the utility even worse, it may damage people´s lives. Islanding detection is a key consideration for grid-connected DG. The effects of islanding detection are not only subject to the strategy it employed, but also subject to the parameter setting. Non-detection zone (NDZ) is an important index to evaluate the performance of islanding detection. In this paper, the NDZs of active frequency drift and active frequency drift with positive feedback (AFDPF) are mapped into two different load space, i.e. L×C_norm space and Q_f0 × C_norm space. Based on it, theoretical deductions are given and simulations are developed to validate the discussions.