Microgrid Protection Using Low-Cost Communication Systems

Power electronics interface of renewable energy to system is now the trend in both transmission and distribution segments of power network. Unlike synchronous generators, the fault feeding and control characteristic of these renewable generators are different and mostly influenced by the topology, switching, and control deployed in power electronics interface. So, the network protection design and operational requirements are now challenged in the absence of large fault current. Although the differential current principle still works, its implementation is limited by the significant cost associated to its communication system. This paper proposes a differential line protection scheme based on local fault detection and comparing binary state outputs of relays at both ends of the line thus requiring a simple, flexible and low bandwidth communication system. The performance of the proposed scheme is assessed through simulation of an example system with several scenarios.