Differential Power Based Selective Phase Tripping for Fault-Resilient Microgrid

Abstract

Modern fault-resilient microgrids (MGs) require the operation of healthy phases during unbalanced short-cir-cuits to improve the system reliability. This study proposes a differential power based selective phase tripping scheme for MGs consisting of synchronous and inverter-interfaced distributed generators(DGs). First, the differential power is computed using the line-end superimposed voltage and current signals. Subsequently, to make the scheme threshold-free, a power coefficient index is derived and used for identifying faulted phases in an MG. The protection scheme is tested on different test cases on a standard MG operating in either grid-connected or islanding mode simulated using PSCAD/EMTDC. The efficacy of the scheme is also assessed on the OPALRT manufactured RTDS platform. Further, the performance of the proposed protection scheme is compared with a few existing methods. The results show that the selective tripping of faulted phases in MGs can be achieved quickly and securely using the proposed scheme.