| Due to the large number of new energy sources such as wind power and photovoltaic(PV)connected to the distribution network,the net peak-valley difference of power system load increases year by year,and the pressure of grid-side peak and frequency regulation increases.It is difficult to satisfy the safe,stable and economical operation requirements of power grid by only relying on the traditional generator sets.In recent years,the development of distributed energy storage technology and the rapid growth of installed capacity have led many scholars to focus on its application on the grid side.However,the power grid cannot directly use distributed energy storage system(DESS)due to its small single capacity,scattered access,and poor controllability.Therefore,this thesis uses aggregators to integrate DESS,fully tap the potential of DESS,and improve the level of power grid regulation.This thesis focuses on the evaluation of user-side aggregable capacity and the optimal allocation of aggregation-side DESS when participating in grid auxiliary services under the distributed energy storage aggregator(DESA)model.The specific work content is as follows:(1)Analyze the operating model of DESA.Firstly,the related concepts of DESA are described,including the definition of DESA,characteristics and advantages of its regulation,DESA's overall architecture and control mode.Secondly,research DESA's operation mode on the grid side and the user side from two levels of business content and transaction methods.Based on the research on the operation mode of DESA,it is concluded that the evaluation of the user-side DESS schedulable capacity and the optimal configuration of the aggregation-side DESS are the key to improving the operation control level and economic benefits of DESA.(2)A user-side schedulable capacity evaluation model based on user participation is proposed.Firstly,analyze the characteristics of a single energy storage on the user side and objective factors such as charging and discharging constraints during operation to obtain the schedulable capacity of a single energy storage during operation.Secondly,evaluate the users' subjective willingness to participate.On the basis of the price incentive model,consider the users' herd mentality,and evaluate the users' initial participation.The users whose initial participation is in the range of ‘participating' and‘non-participating' are treated with uncertainty,and the total number of users who are willing to participate in the aggregation scheduling under each price incentive is obtained.Thirdly,combining the objective factors of DESS operation and users' subjective willingness to participate,a DESS participation schedulable capacity evaluation model is established.Finally,this model is used to calculate the dispatchable capacity of DESS in a certain area.(3)An optimal configuration model of aggregation-side DESS with DESS participating in peak regulation is proposed.When the capacity of user-side DESS cannot meet the demand of grid peak regulation,aggregate-side DESS should be configured to participate in peak regulation together with user-side DESS.Firstly,according to the requirements of the system's peak-shaving capacity and the operation mode of the DESA,the problems of the configuration of the aggregator-side's DESS capacity and location are analyzed.Secondly,a particle swarm optimization(PSO)algorithm is proposed to solve the optimal incentive price and the optimal allocation capacity of the aggregator-side DESS with the goal of maximizing the DESA's annual revenue.Thirdly,with the goal of minimizing the active power loss of the system after aggregator-side DESS is connected,the Matlab program is used to calculate the optimal access point of aggregator-side DESS.Finally,the optimal incentive price scheme,site selection and capacity scheme of the aggregator-side DESS is obtained by using improved IEEE33 distribution network data,which provides a theoretical basis for the establishment of DESA. |
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