Comparison of Non-Detection Zone of frequency drift anti-islanding with closed-loop power controlled Distributed Generators

Abstract

In this paper, the Non Detection Zones (NDZs) of frequency drift anti-islanding were compared according to the structure of positive feedback loop for closed-loop power controlled Distributed Generators (DGs). It was reported that the NDZ of frequency drift anti-islanding is enlarged with closed-loop based constant power controller. On the other hand, some research gives the functionality of the frequency drift anti-islanding even with the closed-loop power controller. If the principle of frequency drift is carefully considered, the positive feedback loop should be modified to maintain the performance of the conventional frequency drift anti-islanding when the cascade outer (power control) loop is constructed. And the NDZ of modified loop would not be degraded by the outer loop. In this paper, the rationale of the modification of the closed-loop is discussed. And, it is shown that the modified feedback loop doesn't degrade the performance of the frequency drift anti-islanding with the closed-loop power controller. The performance of modification is verified by computer simulations and hardware experiments.