| With the promotion of the construction of new power system under the goal of "carbon peak and carbon neutralization",the proportion of wind power,photovoltaic and other renewable energy with random,intermittent and fluctuating characteristics is increasing,and the proportion of traditional thermal power units is decreasing.Although the carbon emission is reduced,it also has a certain impact on the safe and stable operation of power system,increasing the peak valley difference of net load,which poses a challenge to the safe and stable operation of the system.The access of energy storage can alleviate the pressure of system peak shaving and ensure the reliable operation of the system.Therefore,it is of great significance to establish the transaction model of energy storage participating in peak shaving and study the impact of energy storage access on system power flow.In view of the above problems,this paper studies from the following three aspects.First,take the actual new energy output data in a certain region as an example,carry out research on the output characteristics of new energy on multiple time scales of year,month and day;establish a mathematical model of net load peak-valley difference,and analyze the impact of different new energy penetration rates on the net load peak of the system.Considering the influence of valley difference,a method for analyzing the demand of power grid peak regulation under different new energy penetration rates is proposed;considering energy storage as an independent market entity to participate in the peak regulation auxiliary service market,energy storage adopts a step-by-step quotation strategy,and establishes a flexible load joint regulation of thermal power and energy storage.The trading plan before the peak day,and the calculation example results verify that the proposed method can alleviatethe system peak shaving pressure and reduce the system peak shaving cost.Secondly,based on the net load curve after the energy storage stabilizes the peak and valley,the output optimization of each thermal power unit is studied,and the unit combination model is established with the goal of economical and environmental protection.The energy efficiency index was introduced to sort thermal power units,and a day-ahead unit combination model based on the improved priority method was proposed.After determining the unit combination scheme,the NSGA-II algorithm was used to complete the load distribution of thermal power units.The above method can not only allocate the load reasonably,but also improve the computing efficiency.Finally,based on the second and third chapters,the optimization results of the energy storage charging and discharging power and the output of thermal power units are put into the actual system for power flow calculation.The method of solving dynamic power flow online;considering the influence of energy storage access to different nodes on system power flow,set up different scenarios of energy storage access PQ node and PV node for simulation analysis;based on the IEEE57 node system,a numerical example is simulated to verify the proposed method effectiveness.Under the background of high proportion of new energy access,the paper analyzes the impact of wind power and photovoltaic access on the system,from three aspects:the transaction mode of energy storage participating in peak shaving and valley filling,the output optimization strategy of thermal power units and the dynamic power flow calculation of the system Carry out research to provide a reference for high proportion of new energy to take over energy storage peak regulation strategy and thermal power output optimization. |
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