Transient Stability Constrained Adaptive Coordination scheme in a Microgrid Considering Different Network Topologies

The integration of distributed generators (DGs) has significantly impacted utility grid operations, making them more complex and affecting protection systems performance. Issues include bidirectional power flow, voltage profile fluctuations, and dynamic behaviour. Transient stability analysis helps to determine critical clearing time (CCT), which is the maximum time allowed for generator stability to be maintained. In this paper, relay coordination is carried out considering different network topologies that occur due to contingencies of sources as well as lines while maintaining the CCT of the system. A few contingencies have been considered, resulting in the formation of eleven topologies of the microgrid, which are grouped into three clusters using K-means clustering based on their average operating time. The optimal relay settings for all clusters were identified while complying with the CCT criteria using the Genetic Algorithm (GA). The proposed relay coordination scheme is verified on the 7-bus microgrid which is the distribution part of the modified IEEE-14 bus test system.