A Novel Method for Anti-Islanding using Reactive Power

Since the islanding of the PV generation systems can cause a loss of lives and damage to equipments, it has to be avoided by a reliable detection system. In this paper, a novel anti-islanding method is presented. The PV generation system applied to the proposed method maintains the real average output power components of the system by MPPT control, which is similar to the conventional PV system. However, the reactive output power components of the system exist and change periodically. It can induce increases or decreases of frequency of load voltage and current. The proposed method enables islanding detection, in the worst case, no load-variation comparing before removing of the grid. So the method does not have a non-detection zone (NDZ). From the experimental result, it was recognized that the whole procedure, from removing grid to system stop, was finished within 0.5 second