An adaptive overcurrent protection in smart distribution grid

High penetration of distributed energy resources (DERs) creates various protection challenges, such as protection blinding, false tripping, unsynchronized reclosing, etc. Additionally, adaptation of active network management approaches namely demand response and network reconfiguration also threats existing protection practice. In this study, a combination of a local adaptive and communication assisted central protection is proposed, whereby the relay settings are dynamically updated based on online identification of the network topologies and status of DERs. Particularly, the local adaptive protection updates relay settings based on DERs status (ON/OFF) employing locally acquired information, whereas the centralized protection updates the relay settings during major changes in grid topologies: network reconfiguration and switching between islanded and grid-connected modes. The effectiveness of the proposed algorithm is demonstrated through simulation results performed on a medium voltage (10 kV) distribution network using real time digital simulation (RTDS). Simulation results demonstrates that the proposed algorithm provides good discrimination and selectivity of faults during varied network conditions.