Advanced Islanding Detection Functionality for Future Electricity Distribution Networks

Islanding detection methods can be divided into communication-based and local detection-based methods. Proposed local passive detection methods have traditionally been dependent on the distributed generation unit type. A large nondetection zone (NDZ) near a power balance situation and unwanted distributed generation tripping due to other network events have also been major drawbacks of traditional, passive local islanding detection methods. In this paper, a new passive local multicriteria-based islanding detection algorithm with fault detection and islanding verification logic is presented. This new islanding detection algorithm, measuring voltage unbalance and voltage total harmonic distortion from all phases, is able to detect very fast and selectively islanding situations in a perfect power balance without NDZ with a simultaneous utilization of the available fault detection information and novel islanding verification logic. In addition to the new multicriteria-based islanding detection method, the fault detection information and islanding verification logic could also be used together with any other known passive islanding detection methods, that is, parameters which are not specified in the fault-ride-through (FRT) requirements of the future grid codes, to improve the performance of these methods in terms of reliability and speed of detection.