An Optimization Strategy For Cooperative Operation Of "DG-Grid-ED-EV-DS" In Microgrids Of Smart Community

In order to achieve Chinese grand strategic goal of being carbon neutral by 2060,the integration of new energy into the grid has become a necessity.With the increase of the proportion of renewable energy generation and the connection of electric vehicles etc.loads,the stability and economy of the operation of the microgrid in the smart community can not be ignored.The microgrid with CCHP can realize the cascade utilization of energy and reduce the operating costs.At the same time,a variety of energy supplies increase the coupling of the microgrid generator sets,so as to reasonably coordinate the power supply and load demands of the units to achieve the balance between supply and demand.This paper focuses on the coordinated operation of "DG-Grid-ED-EV-DS" microgrid with CCHP in smart community,and the main work is summarized as follows:(1)The virtual energy storage of some controllable loads in intelligent district is studied to suppress the active power fluctuation of higher power grid.Considering the controllable characteristics of air conditioning load and gas storage reserve of natural gas pipeline in residential area,virtual energy storage is established,and the contact line power of microgrid is adjusted by virtual energy storage charge and discharge to reduce the fluctuation of active power in power grid.The active power of the power grid is divided into three types: target frequency band,high frequency band and low frequency band by wavelet transform.The line active power between the superior power grid and the microgrid is close to the target frequency band and the active power changes more smoothly.(2)In view of the "DG-ED-DS" cooperative operation of the microgrid,considering the uncertainties of photovoltaic renewable energy and load,the virtual energy storage of air conditioning group is used to suppress the uncertainties of photovoltaic and load,and the robust optimization model of "DG-ED-DS" cooperative operation of the CCHP microgrid is established with the goal of minimizing the daily operation cost.Robust optimization model is a non-deterministic problem.In order to reduce the computational complexity of the robust optimization model and improve the ability of solving the problem,an improved column constraint generation(C&CG)algorithm was used to solve the robust optimization problem with uncertain sets,which was transformed into a mixed integer linear programming problem that was easy to solve.In winter and summer typical day scenarios,the effect of air-conditioning virtual energy storage on reducing the uncertainty of photovoltaic and load is analyzed.The example results show that the actual cost of the robust optimization model with air-conditioning virtual energy storage is reduced by 5% compared with that of the deterministic model.(3)The collaborative operation of the microgrid "DG-Grid-ED-EV-DS" was studied.Considering the randomness of electric vehicles,Monte Carlo sampling was adopted to simulate the time and state of off-grid and grid-connection of electric vehicles in the community,and virtual energy storage of electric vehicles was constructed.Electric vehicle virtual energy storage is used to cut peak and fill valley,and air conditioning virtual energy storage is used to compensate for active power deviation caused by uncertainty of photovoltaic and load.The robust optimization model of "DG-Grid-ED-EV-DS" cooperative operation of microgrid is established with the goal of minimum voltage deviation and daily operation cost.The robust optimization model is transformed into a mixed integer programming problem by C&CG algorithm.The Mosek solver is used to solve the problem.The results show that the virtual energy storage of electric vehicles reduces the voltage deviation and the daily operation cost of microgrid.