Composite islanding detection method of photovoltaic grid-connected inverter

Islanding detection is an important issue for the distributed grid-connected photovoltaic generation systems. Based on traditional passive islanding detection method and active current amplitude offset method and combining with their advantages, the paper puts forward a new composite islanding detection method, and introduces the principle and realization process of the method. According to the technical specifications of IEEE.Std.2000-929, simulations and experiments of the new method are carried out. The results show that, when the inverter output and the load power are balanced and the load is resistive, the new islanding detection method can detect islanding quickly, have no non-detection zone and little influence on the power quality. What is more, it can reduce the impact on the output power of photovoltaic generation systems.