Research On Operation Strategy Of Integrated Energy System Based On Combined Heat And Electricity Storage

The integrated energy system includes a series of links of energy input,conversion,transmission,storage,and supply,which operates in a flexible manner.It has the advantage of multiple complementary energy sources,providing a new way for the consumption of renewable energy such as wind and solar energy.However,the randomness of renewable energy output brings obstacles to the day-ahead operation method of the system.There is still a phenomenon of "wind and solar curtailment".The fluctuation of renewable energy output and user load is easy to cause a large deviation from the day-ahead plan in the actual operation process,which needs to be adjusted in the intra-day operation process.According to the above situation,the day-ahead operation method and multi-time scale optimal operation method of the integrated energy system are deeply studied in this paper.The multi-energy complementary characteristics of the integrated energy system are efficiently used in the day-ahead operation plan to improve the economy,environmental protection and energy efficiency of the system.In the process of intra-day operation,the work condition of the facilities in the system is updated layer by layer through the multi-time scale operation method to improve the operation reliability of the system.The main contents are as follows:Firstly,the models of renewable energy facilities,energy conversion facilities and energy storage facilities in the system are established.The wind and solar energy resources in specific areas are analyzed.Wind power output diagram and solar thermal collector output diagram of typical days in summer,transition season and winter are generated.Then,the objective function and constraint conditions of the optimization model are determined based on the process of system method.The combined operation method of heat storage and electricity storage is designed then the traditional operation method of separate production and independent operation method of heat storage and electricity storage are designed as comparative reference group.The CPLEX optimizer is used to solve the three methods.The operation results of the combined operation method of heat storage and electricity storage and the two reference methods are compared and analyzed.The results show that the total cost of the combined operation method is reduced by 32.15% compared with the traditional production division method,and by 20.51% compared with the independent operation method,which indicates that the combined operation method can reduce emissions,improve renewable energy utilization rate and economy efficiency.After that,the capacity sensitivity analysis of storage battery and heat storage tank is carried out.The control variate method is used to analyze the total cost of the system when the capacity of storage battery and heat storage tank changes,and the optimal capacity values of both are obtained.Finally,an intraday multi-time scale optimal operation method for the combined operation method of heat storage and electricity storage is proposed to reduce the adverse impact on the system caused by the errors of user load and renewable energy output prediction data in the actual operation process.The multi-scale operation method updates the operation state of the facilities in the system layer by layer through day-ahead scheduling,rolling scheduling,and real-time adjustment stages,which ensures the stable and sufficient supply of user load and increases the reliability of the system operation.The comparison with of the single time scale operation method results shows that the total cost of the multi-time scale method decreases by5.98%,5.25% and 7.43% in summer,transitional season and winter typical days respectively.With the time scale shrinking,the supply balance rate of energy also increases.And the reliability of energy supply is also improved with the continuous reduction of the time scale.It is proved that the multi-scale operation method proposed in this paper can effectively reduce the total operation cost and improve the reliability of the operation method.In this paper,the combined operation method of heat storage and electricity storage is formulated as the day-ahead 24 h overall operation method of IES,and the superiority of the combined operation method is verified by comparing with two comparative reference methods in the numerical simulation.Then,in order to improve the operation stability of the combined operation method in the intra-day scheduling stage,a multi-time scale operation method is developed.The comparison of the multi-time scale operation results with the single-time scale operation method in the numerical simulation proves that the multi-time scale operation method can effectively improve the economy and stability of the system operation.This research provides a reference idea for operation method of IES.