A communication-based strategy for protection of microgrids with looped configuration

• A communication-aided strategy has been proposed to protect looped microgrids in both modes of operation.
• The proposed protection strategy does not require protection mode switching and is independent of fault current levels; and type, size, and location of distributed generators.
• The proposed strategy offers a backup protection in case of communication system failures.
• The proposed protection strategy can be implemented by commercially available relays.
• The paper outlines the structure and key modules of the required digital relay.

One of the main issues associated with the microgrid implementation is to devise an appropriate protection strategy that is effective in both operational modes of the microgrid, that is, the grid-connected mode and the islanded mode. The problem gets even more complicated when the microgrid has a looped configuration. This paper proposes a communication-based strategy for protection of looped/meshed microgrids. The proposed strategy, which can be implemented by commercially available microprocessor-based relays, also offers a backup protection scheme to manage communication network failures. Transient time-domain studies are carried out to verify the effectiveness of the proposed protection strategy for a realistic distribution network simulated in the PSCAD/EMTDC software environment.