Microgrid Differential Protection Based on Superimposed Current Angle Employing Synchrophasors

The inclusion of multi-energy distributed generators (DGs), especially inverter-interfaced generators, presents challenges in the microgrid's protection strategy and operational constraints. The work for designing primary protection mechanism for microgrid is continuously progressing. In this regard, this article presents a positive sequence superimposed current differential angle based protection scheme employing only positive sequence current phasor from both ends of the line. The proposed scheme collects current phasor measurements from the low-cost microphasor measurement units ($\mu$PMUs). The performance of the proposed scheme is analyzed through simulations on a seven-node microgrid in grid-connected and isolated mode operation under various fault and no-fault situations, and also considering the effect of DG penetration level and DGs types. The simulations are also carried out in the IEEE-33 node network considering C37.118.1 standards-compliant PMUs. Furthermore, a real-time control hardware-in-loop testing is performed to further validate the scheme for practical implementation.