A Novel Active Islanding Detection Method of Grid-connected Photovoltaic Inverters Based on Current-Disturbing

A novel method for islanding detection of a grid-connected photovoltaic system is proposed in this paper. Islanding can be more effectively detected through adding periodical disturbing current to the output current of the inverter. Compared with the active frequency drift method, the method has the many merits that it does no harm to utility, doesn't affect the utility frequency and also it does not generate harmonic current and voltage. In addition to, it has the least NDZ (non detection zone). This method has been proved by simulations and experiments