An islanding detection algorithm based on fuzzy adaptive phase drift control

Islanding detection is an indispensable function of grid-connected photovoltaic power generation system, and active phase shift method serves as an effective way to implement it. However, a too small disturbance quantity setting is likely to generate non-detection zone, and an adverse effect on output power quality when the disturbance is oversize. In order to solve the problem, an islanding detection algorithm based on fuzzy adaptive phase drift control is proposed, of which introduced self-adjust accelerating gain into frequency difference positive feedback. Basing on analysis of the relationship between the frequency drift of the point of common coupling voltage and the load characteristics after the initial disturbance, the algorithm parameters are discussed to adapt to frequency drift at different loads during the disconnection of power grid. The simulation and experimental results indicate that the algorithm has short detection time, no non-detection zone and less grid current THD.