Study On Two-stage Optimal Dispatch Strategy Of PV-BESS Integrated System Under TOU Electricity Price And TOU Electricity Price Optimization Study

“Peak carbon dioxide emissions” and “carbon neutrality” are important energy development future goals of China,and the distributed PV-BESS integrated system is one of the significant methods to achieve it.Nevertheless,there are few researches focus on optimal dispatch strategy of distributed PV-BESS integrated system at present.In addition,the existing dispatch strategy researches have some problems,such as poor economy of system operation and inapplicability under low solar radiation intensity scenarios.At the same time,with the increase of the proportion of PV-BESS users in the power grid,due to the influence of special power supply mode on the power grid and the different response forms to TOU electricity price,the traditional TOU electricity price optimization method will have limitations.Base on the problems mentioned above,this paper relies on the National Natural Science Foundation of China "Research on risk assessment and optimization of active distribution system considering demand response" project,carries out research works on the optimization dispatch of PV-BESS integrated system under TOU electricity price,time partition and TOU price optimization model with the consideration of PV-BESS integrated system users,and so on.The main research contents of this paper are as follows:(1)Study on two-stage optimal dispatch strategy of PV-BESS integrated system under TOU electricity price.Combining the dispatch strategy of energy storage system with the optimal dispatch strategy of PV generation system to form the two-stage optimal dispatch strategy of PV-BESS integrated system.Firstly,a dispatching cycle is divided into two stages based on TOU electricity price information,and the concept of scheduling day is introduced to make each stage continuous.Secondly,the charging and discharging power of the energy storage system is optimized by taking the scheduling coefficient as the optimization variable and maximizing user benefits as the optimization objective.Finally,different PV output scenarios are taken to verification,and the result shows that the proposed two-stage optimization dispatch strategy can effectively improve the overall operation efficiency under each scenario.At the same time,it can effectively respond to the TOU price,so as to shift the peak load to the valley time at a certain extent more actively.So that the power grid can reduce the peak load and improve the valley time load,and cut down the difference between peak load and valley load of the power grid.(2)Study on dynamic correction operation strategy for forecast error.Day-ahead dispatching of PV-BESS integrated system is based on accurate prediction of PV output power and load power,but the existing prediction technology cannot achieve absolute accuracy.Hence,this paper proposes a dynamic correction operation strategy in actual operation of PV-BESS integrated system.Based on the difference between the predicted value and the actual value,this strategy adjusts the charging and discharging power of energy storage system,the power bought from grid and the selling power in real time so as to balance the predicted error.The results show that the strategy can adjust the charging and discharging power of energy storage system,the power bought from grid and the selling power in real time to balance the predicted error value,ensure the power balance constraint during the system operation,and update the subsequent scheduling plan to maintain the optimal result of the overall scheduling.(3)Study on TOU electricity price optimization considering energy storage strategy adjustment of PV-BESS integrated system users.Firstly,mathematical modeling is carried out for the special power consumption mode of PV-BESS integrated system users,and the integrated load curve of the power grid containing a certain proportion of PVBESS integrated system users is obtained.Secondly,the time period is divided according to the synthesis load curve of power grid,and the demand side response model which can reflect the energy storage strategy adjustment of optical storage users is constructed based on the elastic matrix of electricity price.Finally,the particle swarm optimization algorithm is used to solve the problem,and the calculation example is analyzed.The results show that the proposed TOU electricity price optimization method can effectively reflect the real load curve of PV-BESS integrated system users after TOU electricity price,and correct the description error of traditional TOU electricity price optimization method on the response curve of PV-BESS integrated system users,so as to minimize the peak load and the difference between peak load and valley load of power grid.