Application of Negative Sequence Voltage Contribution Factor to Detect Islanding

A novel islanding detection method without devastation and without non-detection zone is proposed. Firstly, the topology of the negative sequence of the microgrid is analyzed when the microgrid operates in grid-connected and islanded. Secondly, according to the changes of equivalent impedance of the negative sequence network, a islanding detection method which based on negative sequence voltage contribution factor is proposed. According to the IEEE Std.1547, theoretical analysis and simulation tests are conducted. The results indicate that the proposed method is able to detect the islanding rapidly in the worst case. Also, this method is effective when single-phase and two-phase of breaker are disconnected. Furthermore, trip on false islanding can be avoided. The method achieves the goals of islanding detection.