Differential Negative Sequence Power Angle-Based Protection of Microgrid Feeders

Abstract

The design of accurate and robust protection scheme is one of the major challenges associated with microgrids. In microgrids, detecting faults during measurement noise and their discrimination from switching transients is challenging. To address these issues, this paper designs a protection scheme using the cumulative sum of differential negative-sequence power angle as a fault detection index. The simulation results, obtained using MATLAB/Simulink, show that the proposed scheme accurately detects all the internal faults and efficiently discriminates between internal fault events and other switching events. And it is found that all the faults are precisely detected within the minimum, maximum, and average fault detection time of 18.6, 28.63, and 22.74 msec, respectively. The scheme is further validated for real-time applications by developing an experimental setup using OPAL-RT real-time simulator. It is found that the proposed scheme is independent of the fault types, fault locations, fault inception angle, change in sampling frequency, simultaneous fault, and evolving fault. Furthermore, the proposed scheme is successfully compared with one of the existing schemes and found superior over the existing scheme. Based on the obtained results, it can be said that the scheme is reliable, accurate, discriminative, and consistent for all the considered events.