An innovative islanding detection scheme in distributed generation using rate of change of the ratio of negative and positive sequence superimposed voltage components.

This article presents a unique method for detecting localized islanding in distributed generation (DG) system which connected to the main power grid, using a passive approach. The proposed methodology involves calculating the cumulative sum of rate of change of ratio of negative and positive sequence superimposed voltage components (RCR21) at the distributed generation (DG) side, which is then employed to detect the occurrence of islanding. The current active methodologies deliberately introduce disruptions to the power system, posing potential issues concerning stability, power quality, and overall reliability of the prevailing grid. Passive methods, on the other hand, has a considerable non-detection zone (NDZ). The technique recommended in this article successfully addresses the NDZ issue without introducing any disturbances. To evaluate its effectiveness, PSCAD/EMTDC is employed for simulating a system. The proposed method undergoes several tests on the said system to assess its performance. The results demonstrate that the suggested approach exhibits the minimum NDZ and can distinguish islanding within a remarkably short period of time, significantly faster than a recloser which typically requires 150 ms for detection.