| Large-scale photovoltaic grid connection has exacerbated the frequency adjustment pressure of the power grid.On the one hand,the frequency adjustment tasks of traditional power grids are mainly undertaken by thermal power generation units.The replacement of traditional thermal power generation units by photovoltaic power generation has resulted in a rapid decrease in the frequency adjustment capacity of the system and a decrease in the frequency adjustment capacity of the power grid.On the other hand,the randomness and volatility of photovoltaic power generation increase the uncontrollability of the power supply of the power grid,resulting in an increase in the imbalance of the active power of the power grid,thereby increasing the pressure of frequency adjustment of the power grid.Therefore,the participation of photovoltaic power generation in frequency adjustment and peak shaving of the power grid and improving the controllability of power generation is an important issue under the situation of large-scale photovoltaic grid connection.First,this article introduces and analyzes the mathematical model,circuit topology and control method of photovoltaic array,energy storage battery,energy storage converter,photovoltaic grid-connected inverter in the photovoltaic power station with battery energy storage system.On this basis,the common DC bus light is compared the advantages and disadvantages and application scenarios of the photovoltaic power station with battery energy storage system and the common AC bus photovoltaic power station with battery energy storage system have laid the foundation for subsequent research in this article.Secondly,this paper studies a control strategy for photovoltaic power station with battery energy storage system to participate in grid frequency adjustment and peak shaving.The energy storage battery determines the reference power according to the grid frequency and the peak shaving period.The state of charge of the energy storage battery is divided to ensure that the energy storage battery can coordinate the two modes of frequency adjustment and peak shaving.The energy storage battery output constraint coefficient based on the state of charge feedback is designed to optimize the output characteristics of the energy storage battery.Build a model of optical storage system in MATLAB / Simulink software,carry out simulation and economic analysis of calculation examples to verify the effectiveness of the proposed optical storage systemto participate in the integrated control strategy of frequency and peak regulation of power grid.Combined with the pilot project,a signal generator test and a power grid experiment were conducted to verify the effectiveness of the control strategy.Finally,this paper studies the control strategy of the photovoltaic power station with battery energy storage system with frequency adjustment and peak shaving to improve the accuracy of the pre-generation plan execution.According to the evaluation method of the grid for the accuracy of the implementation of the photovoltaic power plant pre-generation plan,the main influencing factors of the photovoltaic power station's pre-generation plan execution accuracy cannot meet the grid evaluation standard.A control strategy to improve the accuracy of power generation plan execution is proposed and the effectiveness of the control strategy is verified through simulation.Combined with the control strategy of frequency adjustment and peak shaving of the photovoltaic power station with battery energy storage system,this paper proposes a comprehensive control strategy to improve the accuracy of the power generation plan execution based on the ability of the frequency adjustment and peak shaving of the photovoltaic power station with battery energy storage system.In MATLAB / Simulink software,numerical simulation and economic analysis are performed.Verify the effectiveness of the proposed comprehensive control strategy. |
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