Resilience Improvement With Zero Load Curtailment by Multi-Microgrid Based on System of Systems

This article studies the resilience and energy management in multi-microgrid system. In the proposed model, the microgrid is formed by four sub-microgrids. Based on the system of systems (SOS), these sub-microgrids pool their resources and capacities together to form a new and more complex microgrid that provides further functionality than the basic separated microgrids. One of the sub-microgrids is connected to the external grid. The tie-line connections are between all sub-microgrids. Some connections are normally-open and the rest are normally-closed. The status of normally-open connections is changed to close when the resilience or economic criteria dictate. The sub-microgrids are integrated with solar panels, wind turbines, battery energy storage (BES) and loads. All sub-microgrids are also equipped with diesel generator as emergency resource. Under normal operating condition, the proposed model optimally utilizes the resources of all sub-microgrids to minimize the cost, pools the extra resources of sub-microgrids, and optimizes the operation of batteries and diesel generators. Under faulty operating condition when some or all sub-microgrids are islanded, the model supplies the loads with zero load curtailment and minimizes the costs. In the faulty condition, the model may change the status of connections from normally-open to close when required. The simulation results on a given test system verify that the recommended model confirms optimal operation of the microgrid. Furthermore, all sub-microgrids, improves resilience, minimizes operating cost, handles the events and achieves zero load curtailment under both faulty and healthy conditions.