Research On Optimal Dispatch Of Park Integrated Energy System Based On Conditional Value At Risk Theory

The development of integrated energy systems helps increase the consumption of new energy and improve energy efficiency.The uncertainty of photovoltaic output and load demand has an impact on the optimal operation of the integrated energy system.The multi-energy complementary park is one of the main forms of integrated energy system planning.Therefore,it is of great significance to study the optimal scheduling strategy of the park integrated energy system that takes into account the economics of operation and the uncertainty of forecasting.First,take a typical multi-energy complementary park as an example,introduce the system structure of the park,analyze the energy flow and the modeling process of the mathematical model of the energy coupling equipment in the system,establish the park integrated energy system model.Lay the foundation for the following chapters to study the optimal dispatch of the park’s integrated energy systemSecond,with the goal of minimizing the operation cost of the park within 24 hours a day,a day-ahead economic scheduling model of the park is established that considers multi-energy complementarity.The economic dispatch model is linearized and transformed into a mixed integer linear economic dispatch model.The algorithm principle of the branch and bound method is analyzed,and the model is solved by this method.The results of the example verify the economic efficiency of using energy coupling equipment and energy storage equipment optimization.Third,considering the uncertainty of load demand and photovoltaic output forecasting,the Latin hypercube sampling and spanning tree method are used to construct multi-random variable scenes,and the synchronous back-generation elimination method is used to reduce the number of scenes,therefore a typical scene set of load demand and photovoltaic output is established.Use risk assessment tool CVaR(conditional value at risk)in finance to quantify the load loss risk of the park system and add it to the objective function.Based on the model established in Chapter 3,Day-ahead optimal scheduling model of the park is established based on CVaR theory.The objective function is the minimum operating cost and the compensation for loss of power loss.The model is solved by branch and bound method.Comparing the results of CVaR model scheduling with traditional economic scheduling,the results show that the established CVaR scheduling model can effectively reduce the risk of system load loss caused by uncertain scenarios,especially extreme scenarios.Finally,a day-ahead-day coordination and optimization scheduling model based on the model predictive control strategy is established.The day-ahead economic dispatch formulates a park scheduling plan.The intra-day scheduling is based on model predictive control,and the conditional risk value CVaR describing the risk of load loss is added to the intraday rolling optimization strategy,and the intra-day scheduling plan is revised following changes in photovoltaic output and load demand.The objective function of the intra-day scheduling model is the minimum cost including the park energy purchase cost,the penalty cost of abandoning the light,the scheduling default cost and the compensation cost for the loss of load risk.Use branch and bound method to solve the model.The results of the calculation example verify the advantages of the day-ahead-day coordinated optimal scheduling model based on the model predictive control strategy compared with a single open-loop day-ahead optimal scheduling model in terms of economy and processing uncertainty.Day-ahead economic dispatch and intra-day rolling optimal dispatch jointly constitute the park’s integrated energy system dispatch strategy,and realize the optimal dispatch of the park’s integrated energy system.