| With the large-scale use of new energy sources and the improvement of the people's living standards,the power variations at both ends of the source and the load are more complex and diverse,which exacerbates the frequency instability of the power system and puts forward higher requirements for frequency adjustment of the power system.There exists the problems in traditional power plants,such as the slow response and low climbing speed.However,the rapid response and accurate response characteristics of energy storage batteries can fill in these deficiencies.The adoption of energy storage batteries for auxiliary power grid frequency tuning has been widely recognized in the industry,and domestic and foreign countries have successively carried out demonstration projects on the participation of energy stora ge in grid frequency regulation.How to play the advantage of energy storage battery in grid frequency modulation has become a hot issue in the current research.This paper focuses on the application of ultra-short term load forecasting in energy storage participation in frequency regulation control.The main contents are as follows:First,the characteristics of load and wind power fluctuation and their influence on the frequency of the power system are studied.The characteristics of load fluctuation and wind power fluctuation characteristics were analyzed by using moving average method,the low pass filter method,difference of load fluctuation quantity extracted method.We judge the load changes and fluctuations of wind power calculation related characteristics,combined with the numerical analysis of the influence of the fluctuation of typical wind power on power system frequency,and summarize the impact of wind power on power system frequency control.Secondly,the basic principle and simulation model of power system frequency modulation are studied.The frequency characteristics of the generator and load of electric power system in a frequency modulation and two frequency modulation work mode and work characteristics are described.Primary frequency modulation regional simulation model is established according to the primary frequency modulation structure process,and simulation and analysis of the thermal power units with different types in primary frequency grid are done as well.The defects and shortcomings of conventional unit participation in frequency modulation are analyzed,and four methods of modeling the equivalent model of energy storage battery and their advantages and disadvantages are discussed.The last is verified by numerical simulations of energy storage auxiliary conventional units in the grid frequency advantage,and the current energy storage in key and difficult problems of frequency modulation in grid are summarized,the necessity of ultra-prediction applied in energy storage in the grid frequency short term load is analyzed as well.Finally,based on the ultra-short term load forecasting,a new energy storage auxiliary conventional unit to participate in the power grid frequency m odulation control method is proposed.The working state area of energy storage is defined and divided,and the system frequency deviation prediction is carried out based on the results of ultra-short term load forecasting.The necessary parameters of energ y storage state identification are obtained through data identification of system frequency deviation prediction results.The adaptive control strategy of storage energy in frequency regulation working state and the energy storage SOC(State of Charge)recovery strategy considering load forecasting are formulated respectively.The simulation of the proposed strategy and conventional control strategy validate that the proposed adaptive short-term load forecasting based on dynamic output + SOC benchmark method can contribute more frequency regulation capacity to meet the requirements under the premise of frequency regulation and improve storage capacity utilization,thereby reducing the demand for energy storage capacity allocation. |
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