Operation Optimization Method Of Microgrid With CCHP Systems For Hydro-wind-solar Energy Complementation

Improving energy use efficiency and reducing pollutant emissions have become the development trend of energy economy and an important driving force for global economic development and sustainable development of mankind.Based on the principle of energy cascade utilization,the CCHP microgrid can simultaneously meet the demands of cooling and heating power load.It has the advantages of high primary energy utilization efficiency,flexible energy supply mode,high power supply reliability and green environmental protection.It has become an important technical means to solve the energy crisis and reduce environmental pollution.Therefore,in combination with the structural characteristics of the CCHP microgrid and the operating characteristics of the equipment,it is of great significance to deeply analyze the optimization of the CCHP microgrid in complex operating environments.This paper mainly studies the optimization model of CCHP microgrid with hydro-wind-solar energy complementation.The specific research contents are summarized as follows:(1)In order to decouple the strong coupling of the thermoelectric output of the micro-turbine,the purpose is to make the micro-turbine actively participates in the operation optimization of the CCHP microgrid.Firstly,it introduces the gas boiler and the heat supply mechanism of the CCHP microgrid to decouple the strong coupling of the thermoelectric output of the micro-turbine,and realizes the collaborative optimization of the electro-thermal energy flow in the CCHP microgrid.Secondly,it analyzes the principle basis of water-wind-solar complementary characteristics and establish the operation optimization model of microgrid based on electro-thermal collaboration,the objective function is the total daily operating cost of the CCHP microgrid,and the interior point method based on Hessian matrix iteration is used to solve the optimization model.The operation cost of the proposed model is reduced by 223.62 yuan and 74.87 yuan,respectively,compared with that of the CCHP microgrid with no hydro-wind-solar energy complementation and the CCHP microgrid with micro-turbine running under the thermal fixed electricity model.It is verified that the electrothermal collaborative mode has better effect in improving the operation economy.(2)In order to solve the problem of the error in the day-ahead prediction of the source load,based on the study of the interval and linear programming mathematical theory,the operation optimization model of the CCHP microgrid is established based on the intervalprogramming.The optimization model is divided into lower limit sub model and upper limit sub model by cross step method.The model is solved by using the IPOPT optimization toolbox in MATLAB programming environment.The model mainly deals with the uncertainty of source load prediction by adjusting the output power of micro-turbine to ensure that the CCHP microgrid still has certain economy under the uncertainty of source load.Compared with the CCHP microgrid without energy storage,when the storage battery is configured,the operation cost is reduced from the range [1143.71414.5] to the range[1110.71365.7],and the model's ability to deal with uncertainty is improved.(3)In order to solve the uncertainty of wind and solar and other forms of disturbances under different time sections of the CCHP microgrid,the feedback link in model predictive control is used to suppress various disturbances,and then the double-layer operation optimization model of the CCHP microgrid based on model predictive control is established.The upper-layer model of the day-ahead time section minimizes the operating costs of the CCHP microgrid,and the lower-layer model of the within-day time section model handles the forecast error and disturbance.Different solvers are used to solve the model in MATLAB environment.Under the schemes of peak-valley and peak-valley-flat electricity price,the two-layer model of CCHP microgrid with different time sections is 9.21% and 8.89% higher in economy than the single-layer model respectively.When the wind and solar prediction error increases from 10% to 40%,the charging and discharging power of the super capacitor increases from 16.74 k W,25.6k W to 26.69 k W,29.74 k W.The ability of the model to deal with uncertainty and improve economy is verified.