Restoration of fuse-recloser coordination in distribution system with high DG penetration

Conventional distribution systems are radial in nature and use time-coordination for protection against disturbances. However, the recent trend of installing embedded distributed generation (DG) has raised concerns regarding disruption of radial nature of existing distribution networks and thus disturbing the coordination of the protective devices. A protection scheme using power electronics switch is proposed in this paper. The scheme ensures the restoration of original radial nature of the system. It is based on the principle of disconnecting DGs before the recloser or any of the fuse has chance to operate. It does not require major protection system upgrade. Developing an approximate fuse model accurate enough to be able to simulate its protective function was a part of this research. Simulations are carried out in PSCAD/EMTDCTM software.