Coordination control of distributed generators and load resources for frequency restoration in isolated urban microgrids

Urban microgrids have become the main body of energy consumption in modern power systems. To reduce carbon emissions, distributed generators (DGs), such as roof photovoltaics (PVs), are increasing rapidly in urban microgrids. By utilizing the power output from local DGs, more microgrids have the ability to operate in isolated mode. However, isolated microgrids have less regulation capacities compared with large interconnected power systems, which significantly raises the difficulty for maintaining the stable operation of isolated microgrids. To address this issue, this paper proposes a coordination control method to tap flexibility from both DGs in supply-side and load resources in demand-side. First, the microgrid model with high -penetration DGs is developed considering virtual power plants (VPPs) by aggregating flexible loads. Then, a coordination control framework is proposed for DGs and VPPs in multi-scenarios, including stable operation, uncertain load disturbances, and accidental DG outages. Based on this framework, a distributed consensus algorithm (DCA) and a local control algorithm (LCA) are designed for DGs and VPPs, respectively. The DCA can achieve a quick regulation of DGs with high plug-and-play expansibility. The LCA can control VPPs considering both the quality of regulation services and comfortable requirements of heterogeneous users. Finally, numerical studies verify that the proposed models and methods can awaken fragmented DGs and VPPs to improve the stability and enhance the resilience of isolated microgrids.