| The output power of wind and solar power generation is fluctuant and intermittent,and its large-scale grid connection brings major challenges to the stable operation of power grid.The traditional thermal power units have problems such as long response time and low regulation efficiency during the frequency regulation process,which cannot well solve the needs of various new energy grid connected and adapt to the fast track of power grid development.Under the background of new energy grid connected generation,how to ensure the safety and stability of system frequency has become one of the challenges facing the power grid.The rapid development of energy storage technology provides a new direction to solve these problems.The battery energy storage technology has a fast and accurate tracking ability,which can well assist conventional thermal power units to adjust the frequency of the power grid,and has important theoretical and practical value in improving the safety performance of the power grid and the ability to accept new energy.Therefore,based on the participation of conventional thermal power units in grid frequency modulation,this paper studies the promotion effect of large-scale energy storage battery assisted thermal power units participating in grid frequency modulation,and optimizes the control of auxiliary thermal power units participating in grid frequency modulation.The main research contents are as follows:1.Based on the principle of frequency regulation of power grid,the operation mode and mechanism of frequency regulation of conventional power grid are introduced.On this basis,the main components of the battery energy storage system,the working principle of the battery energy storage system participating in grid frequency modulation and the advantages of frequency modulation are introduced.2.The power grid model of auxiliary thermal power unit frequency modulation by battery energy storage system is constructed.According tothe working mode and physical structure of conventional regional power grid,the simulation model of traditional thermal power units participating in power grid frequency modulation is constructed;the simulation model of auxiliary thermal power units participating in power grid frequency modulation by battery energy storage system is established by analyzing the working characteristics of energy storage battery,and the effect of auxiliary thermal power units participating in power grid frequency modulation by battery energy storage system is studied.The results prove that the battery energy storage system participates in the frequency regulation of the grid efficiently.3.In terms of the battery energy storage system assisting the thermal power unit to participate in the optimization control of the frequency regulation of the power grid,for the primary frequency regulation,based on the traditional droop control,the output power of the battery energy storage system can be controlled by the real-time correction of the droop coefficient of the battery energy storage system through the state of charge.Aiming at the secondary frequency modulation,considering the load demand of the regional power grid and the state of charge of the battery energy storage system,a multivariable fuzzy control strategy is proposed to realize the power control and protection of the battery energy storage system.The simulation model was built and verified,and the results show that the proposed control strategy has more advantages in improving the frequency modulation effect of the regional power grid and increasing the service life of the energy storage device. |
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