Microgrid differential protection scheme using downsampling empirical mode decomposition and Teager energy operator

Abstract

This paper proposes a differential protection scheme for microgrid based on spectral energy content and phasor deviation of the current signals. A noise robust downsample based empirical mode decomposition (DEMD) technique is employed for fetching intrinsic mode functions (IMFs) of current and voltage waveforms. Teager energy operator is applied for tracking the instantaneous energy content of the IMFs. Pearson correlation coefficient between voltage and current waveforms is used as an estimation for phasor deviation. Finally, a simple threshold is outlined for the identification of fault and no-fault conditions. The proposed scheme is extensively validated for fault and no-fault situations with wide variations in operating parameters for radial and loop topology in grid-connected and islanded modes of operation. The performance is found to be satisfactory in terms of dependability, security, and speed. Simulation results also show the immunity of the proposed method against data synchronization error. Because of the low computational complexity of the DEMD algorithm and the use of a simple threshold for classification, this method is feasible and competent for real-time applications.