IEC61850 Based Integrated Directional Power Relaying for the Protection of Microgrids against Unbalanced Fault Conditions

This paper deals with an integrated directional relaying scheme for the protection of buses and lines of microgrid against asymmetrical fault conditions. The proposed scheme detects the asymmetrical faults and unbalanced conditions by tracking the unbalanced power measured at relaying points, and distinguishes the fault direction by monitoring the sign of negative sequence reactive power flow. Computer simulation studies show that the proposed scheme provides fast detection and tripping for the fault at buses and lines of the active distribution network. Integrated bus protection scheme has also been installed in IEC 61850 communications frame to test the performance of substation internal communication and the bus protection scheme.