Detection, classification, and location of faults on grid-connected and islanded AC microgrid

A new spectral energy differential protection scheme using sparse Fourier kernel fast time-frequency transform is proposed for the detection, classification, and location of faults either on the grid-connected or islanded AC microgrid. Initially, the three-phase average and differential components of the current samples measured on either side of the distribution line are processed through an alteration detection filter, which identifies the fault incipient and consequently registers an alteration index for the particular phase, which identifies the fault. The spectral energy of the differential current components are than computed to classify the type of the fault under a number of intrinsic operating conditions like the meshed and radial architectures and grid-connected or islanded mode of operation and varying fault distance ratios. Extensive numerical experimentation illustrates satisfactory results for all the cases investigated in this paper, which include detection, classification, and location of faults on the microgrid.