Overview of anti-islanding US patents for grid-connected inverters

Recent rapid interest in renewable energy generation, especially high penetration of the grid-connected photovoltaic system, is imposing new challenges to the anti-islanding protection. In practice, there is a potential risk of failure for anti-islanding protection due to the interaction between different islanding detection algorithms. It is of great importance to identify which kind of islanding detection methods are used in field applications for further analysis of this interaction problem. Although many anti-islanding detection methods have been reported in the last decades, most of them have been presented and discussed from the academic point of view, and they are very interesting, but complicated to implement and might not be practical for real applications. Therefore, the objective of this paper is to provide a comprehensive review of relevant international patents to find out the potential anti-islanding algorithms in real applications, which would be useful for the further investigations of interaction between different anti-islanding algorithms in a real distributed grid.