PMU based islanding detection method for large photovoltaic power station

With the application of synchronous phasor measuring units (PMU) and the development of wide area measurement system (WAMS) on power systems, islanding detection of large photovoltaic (PV) power station can be implemented based on communication and embed islanding detection function on central management unit (CMU), instead of on PV inverters. This paper discussed an islanding detection method based on synchronous phasor measurement technology, or on WAMS which collects the frequencies of photovoltaic power station and the connected utility. The discussed method can release the conflict in satisfying national code demands for large photovoltaic power station: low voltage ride through (LVRT) and islanding detection. The frequency difference between photovoltaic power station and the utility is main index to distinguish islanding. The paper developed simulations using MATLAB/Simulink to discuss frequency performance of grid in power mismatch result from load shedding, generator tripping, and islanding events. Simulation results show that the frequency performance of PV stations have difference with those in synchronous machine power system. The criteria rule of islanding detection and threshold setting for algorithm are discussed to provide guide for PV station applications.