Security Constrained Operation of Radial Micro Grids Based on the Loads’ Vulnerabilities and Flexibilities

This paper proposes a mathematical model for the short-term security constrained operation problem in a radial Microgrid. The conventional security modeling in the transmission system is not appropriate for radial networks, where, a line outage creates an island and usually leads to the load shedding. This paper proposes a security model for the radial Microgrid using the consumers’ damage indices. In addition, it analyses the load control effects. It includes these contingency state constraints in the short-term scheduling: power balance in the island, allowed frequency deviation range, island’s capability to continue the service and load sensitivity to the duration of the abnormal condition. Hourly scheduling of the resources, loads and power exchange with the main grid is performed with the aim of minimizing the load damage in the contingency states and maximizing the profit at this selected security level. The proposed model is applied to IEEE 123-bus test system.  It reduces the load damage index at least 38% in comparison to the other operational strategies. The cost-benefit assessment is performed to analyze the proposed method in different viewpoints.