Research On Operation Optimization Of The Combined Cooling,heating And Power Micro Energy Grid

With the intensification of energy shortages and environmental pollution,combined cooling,heating and power(CCHP)has received extensive attention as the main development direction and form of distributed energy system.The combined cooling,heating and power micro energy grid extends from the micro grid.It is a small integrated energy system that contains various distributed energy sources and meet the needs of various energy sources such as cold,heat and electricity.The development of micro energy grid can promote large-scale access to distributed power sources,achieve multi energy complementation and provide high reliability supply of loads with various energy forms.Research on economic optimization of the combined cooling,heating and power micro energy grid include capacity optimization and operation optimization.This paper focuses the operation optimization,which can achieve the optimal economic operation of micro energy grid by optimizing outputs of distributed power at all times under the premise of determining the capacities of the main devices in the micro energy grid.The main research work include the following aspects:At first,developments and research status quo of CCHP and micro energy grid at home and abroad are introduced.In this paper,operation strategies of micro energy grid are explained,which are composed of grid connected operation and isolated island operation.By studying the energy structure of micro energy grid and the operating characteristics of the devices,this paper establishes the mathematical models of the photovoltaic,wind turbine,micro turbine,gas boiler,refrigerator,battery,and thermal storage device.Secondly,the energy structure of CCHP system and three operation modes are analyzed and studied.Taking the operation cost of the CCHP system as the goal,the economic operation optimization model of CCHP system is established.Based the case study,this paper compares the optimal results of three operation modes.This paper analyzes the economic influences factors,which include electricity prices,gas prices,networking strategies,load ratio,operation modes.Then,take the operation cost of CCHP micro energy grid as the goal,which consists of fuel cost,management cost of devices,start-up and shut-down cost of devices,purchased electricity cost from power grid.Considering the constraints of the energy balances and the outputs of devices,the economic operation model of CCHP micro energy grid is established.What's more,hybrid particle swarm optimization algorithm is proposed to solve the model.By case simulation in different typical days with different electricity price mechanism,scheduling schemes of CCHP micro energy grid are obtained.By summarizing and analyzing the optimal operation strategies of micro energy grid,the rationality and effectiveness of the proposed model and algorithm are verified.Finally,taking the daily operation cost,the daily environment cost and the primary energy rate as the goals,a multi-objective optimization model is established.Based on the principle of maximum membership,the fuzzy optimization method is used to transform the multi-objective optimization problem into a nonlinear single objective optimization problem.Comparing the multi-objective optimization results with the single objective optimization results,the multi-objective optimization can better reflect the actual operation of CCHP micro energy grid and coordinate the relationship of economy,environment and energy utilization.