Energy Storage And Frequency Regulation In Isolated Highway Microgrids With Virtual Inertia And Virtual Damping

Under the severe challenges of resource shortage,climate change,and environmental pollution brought about by the rapid development of expressways,the integrated development of transportation and energy are an inevitable trend and practical demand for the development of China’s energy system in the transportation field towards high efficiency,high flexibility,and greening.However,due to the uncertainty of renewable energy output,such as wind power and photovoltaics,and the limited frequency regulation effect of existing energy storage,more stringent requirements are put forward to accurate predict of frequency response and safety and stability control of highway microgrids.Therefore,it is of great significance to construct the frequency response model of the microgrid and study the optimization method of energy storage frequency regulation control to maintain the frequency stability of the system.The main contents and achievements of this thesis are as follows:Based on the topology of the highway island microgrid system,this thesis proposes a method to classify distributed power by inertial type.It synthesizes the established wind turbine,photovoltaic high-fluctuation output model,and power supply model of the energy storage battery to construct a low-order frequency response model of the highway island microgrid.Based on the above,a virtual inertial damping strategy is proposed to control the output of energy storage batteries to improve the inertia and damping of highway island microgrids.The low-order frequency response model of the microgrid based on virtual inertial damping control is simulated for highway tunnel scenes and service area scenes,and the simulation results show that the virtual inertial damping control improves the frequency stability of the system to a certain extent.On the basis of the above,this paper applies Model Predictive Control(MPC)to virtual inertial damping control,considering the minimization of the sum of frequency deviation and frequency deviation change rate as the objective function and combining MPC with rolling prediction and feedback of the system model variables on the basis of the state space prediction model of highway islanded microgrid.Based on the highway islanding microgrid state space prediction model,the system model variables are continuously rolled and corrected with MPC to achieve real-time updates of the inertia and damping coefficients,thus improving the inertia response capability of the energy storage battery.The simulation results show that the proposed strategy can effectively improve the dynamic quality of the system frequency response.The research results of this thesis theoretically enrich the construction system of the frequency response model of highway island microgrid,broaden the strategy and method of energy storage frequency regulation,have specific theoretical research and practical guiding significance,and provide new ideas and methods for ensuring the safe and stable operation of the microgrid.