Optimal Control Strategy Of Wind And Energy Combined System Participating In Primary Frequency Regulation Of Power System

The wind power has the characteristics of fluctuation and intermittence,which will lead to an increase in the burden of frequency regulation after wind power is connected to the grid.The response time of conventional frequency regulation unit is too long to meet the current requirements of power system frequency regulation,which will lead to a more serious problem of primary frequency modulation in power system with wind power.The characteristics of rapid changing of wind power output make it possible for wind turbines to participate in primary frequency modulation.However,the conventional inertial response capacity of wind turbines is small.The energy storage system(ESS)with fast charging capacity are always cooperated with wind power to participate in the primary frequency regulation of power system.Therefore,it is an important issue to study the coordinated control strategy of primary frequency regulation of power system for energy storage system and wind farm.Firstly,this article studies the impact of wind power into the power system on primary frequency regulation and the regulating ability of ESS in primary frequency regulation.The change ratio of demand for primary frequency regulation action is given by analyzing datas.Considering the frequency drop of power system under the same disturbance and different wind power permeability,the influence of wind power permeability on primary frequency regulation of power system is studied.Based on the actual operation parameters of power system,the mathematical model of primary frequency regulation of power grid involving thermal power unit,hydropower unit,wind power unit and energy storage system is established.Based on the same wind power permeability,the influence of ESS on the frequency of power system is studied.And the primary frequency regulation ability of energy storage system is verified.Secondly,the optimal control strategy of wind power and ESS combined system participating in primary frequency regulation of power system is studied.Considering the requirement of paying equal attention to the primary frequency regulation effect and the economy of frequency regulation in the actual operation of power system,taking into account the advantages of serial and parallel control strategies of traditional wind-storage system,the maximum deviation frequency,steady-state frequency value and energy storage capacity requirement are comprehensively measured,and the optimal control strategy of wind-storage combined system is proposed.Using the control variable method and taking the minimum objective function as the simulation,the serial allocation proportion of the optimal control strategy and the reduction of the output time of the energy storage system are determined.Basedon Simulink simulation software,the primary frequency regulation effect of different control strategies for wind-storage combined system is studied.Finally,the comprehensive evaluation method of wind-storage combined system participating in primary frequency regulation of power system is studied.Considering the primary frequency regulation effect of different control strategies for wind storage combined system and the cost,benefit,penalty and compensation of wind storage system participating in primary frequency regulation service of power system,a comprehensive evaluation method of wind storage system participating in primary frequency regulation of power system is proposed.Based on this evaluation method,the primary frequency regulation effect of the combined wind storage system using serial,parallel and optimized control strategy is evaluated comprehensively.Therefore,the research on the optimal control strategy of wind storage combined system participating in primary frequency regulation of power system has certain reference value for improving wind power connection.And this reach has certain engineering reference significance.