A Novel Scheme for AC Microgrid Protection Based on Differential Phase Angle of Fault Component Current

In the last decades, microgrids have been developed for the techno-economic management of distributed generation (DG) penetration in distribution networks. Providing a primary secure and dependable protection scheme for AC microgrids is a challenging task due to the use of a variety of DG technologies. In this paper, a new independent protection scheme using current synchrophasor measurements obtained from microgrid buses is presented to detect the different kind of internal and external faults in different location. The performance of the proposed protection scheme is evaluated under different operating conditions of the microgrid (in the grid connected and islanded mode) by entering and disconnecting the DGs and changing their penetration level.  In this regards, a novel index based on differential phase angle of fault component current obtained from both ends measurements of microgrid buses is proposed to distinguish the fault condition from no-fault situations. The proposed protection index is tested on standard 15-bus microgrid considering high resistance faults and variation in DG penetration in the grid connected and islanded mode. The obtained results indicate the capability and superiority of the proposed approach in reliable microgrid protection