A Robust Anti-islanding Method for Grid-Connected Photovoltaic Inverter

In a modern power system, photovoltaic as distributed generated source is growing larger and it can cause a variety of problem. Most issued problem is an islanding phenomenon. In order to prevent islanding phenomenon, three kinds of active islanding detection methods have been studied. These are respectively to change magnitude, frequency, and the start phase of inverter output current. Among them, both frequency and start phase variation anti-methods make the islanding frequency drift away from the trip window of the frequency relay if an islanding is occurred. This paper presents a robust anti-islanding method, which are consisted of a frequency variation method as AFD (active frequency drift) method and a start phase variation method as SMS (slip mode frequency shift) method. Clearly, the proposed anti-islanding method shows the satisfied islanding detection ability to IEEE 1547 Standard. To validate the performance of the proposed method, simulation and experiment are performed. Possible islanding conditions are followed by the IEEE Standard 1547. The methodology presented in the paper can be extended to the other active anti-islanding methods