Detection of islanding in microgrid using wavelet-MRA

With the advent of distributed generation (DG) systems, there is a demand of reliable and uninterrupted power supply to the consumers. Microgrids are a group of distributed generators that are tied to a distribution system to satisfy the local electrical loads. One of the major operational issues in the microgrid in synchronous mode with the main grid is islanding operation in the event of any disturbance on the grid side (i.e. short circuit faults). During the occurrence of such faults, protecting a microgrid and all other electrical equipment is really essential. Hence a reliable, fault detecting methodology is required to detect the islanding condition and protect the DGs in case of any fault. A novel approach for the isolation of the DG, on the occurrence of a fault on the grid side has been presented in this paper. This isolation is marked by examining the three phase current at the point of common coupling using Wavelet Transform (WT) Multi-Resolution Analysis (MRA). The simulation studied in MATLAB shows that this technique can automatically detect all the ten types of shunt faults that can occur on the grid side. The result validates the proposed islanding detection technique to be robust and accurate.