A Concurrent Deviation Similarity Based Differential Protection Scheme for Inverter Based Islanded Microgrids

Fault detection in Inverter-Based Islanded Microgrids (IBIMGs) is challenging because of a restricted fault currents, rendering traditional protection schemes inadequate. This paper proposes an advanced differential protection system using the Concurrent Deviation Correlation Method (CDCM) to enhance reliability and speed in fault detection. The proposed scheme evaluates the Concurrent Deviation Correlation Coefficient (CDCC) to assess correlations between current deviations at the ends of the two lines. In addition, a Fault Detection Indicator (FDI) is defined to differentiate between internal and exterior faults. Simulations conducted on a modified IEEE 33 bus system using PSCAD/EMTDC and MATLAB. Results show that the proposed method achieves accurate fault detection across all fault types. Also, it demonstrates robustness against measuring errors, noise, synchronization error, and varying fault resistances. Consequently, the scheme enables rapid fault identification, with detection times reduced by over 50% compared to traditional methods, significantly improving operational reliability in IBIMGs.