Protection of meshed microgrids with communication overlay

The higher reliability of meshed grids, whether in power or communication, when compared with radial grids is well established. However, while meshed grids provide higher reliability, protection of meshed grids is challenging. In smaller systems such as microgrids, line impedances can be small and many branches may experience approximately the same level of fault current. Locating faults quickly before damage to the equipment and system occurs becomes a non-trivial task and cannot be achieved without communication. This paper discusses a comprehensive scheme for protecting meshed microgrids with multiple levels of protection for redundancy. Power line carrier (PLC) technology is proposed as cost effective and robust means of communication, obviating the need for additional cabling.