Research On Primary Frequency Regulation Of Wind-thermal Power Coordination

The construction of a new power system with new energy as the main body is the main energy development goal to achieve peak carbon dioxide emissions,carbon neutrality.The access of large-scale new energy will form a high proportion of power electronic power system with converter as the interface,which will gradually replace the traditional synchronous generator units in the power system and become the development trend of the new power system in the future.However,with the continuous growth of the proportion of new energy,the level of rotational inertia of high proportion electronic power system continues to decline,which significantly reduces the frequency regulation capability of power system under active power disturbance fault and there is a certain risk of frequency instability.Therefore,the new energy generation system represented by wind turbines should have the frequency response capability of traditional synchronous units,and the frequency stability of the system should be improved by adding additional frequency control links under the background of the new power system.In this paper,based on the minimum inertia demand of the system: firstly,the frequency regulation mechanism of wind turbine output inertia participating in the system is studied in the full wind speed range.Secondly,the control scheme and strategy of wind-fire cooperative frequency regulation are constructed in an all-round way,combined with the inertia control of traditional thermal power units and considering the frequency characteristics of load.Finally,a simulation example is given to verify the effectiveness and feasibility of the proposed method and scheme.1.To study the inertia control in the full wind speed section of wind turbine with doubly-fed wind turbine as the research object.Calculate of the output inertia of wind turbine and evaluate the frequency regulation capability of the wind turbine using rotor kinetic control and power standby control.The optimal exit frequency regulation strategy of wind turbine is studied to avoid the secondary frequency drop accident of the system under the rotor kinetic energy control strategy.The equivalent inertia output model of wind farm is established according to the inertia control and frequency regulation capability evaluation of wind turbine.The inertia control and frequency regulation capability evaluation of the wind farm are studied to ensure the maximum power generation benefit of the wind farm.2.The evaluation method of minimum inertia demand under active power disturbance fault is studied,considering the frequency regulation characteristics of synchronous units,the frequency characteristics of load,and the constraints of frequency change rate and frequency offset.The inertia output control method of the wind farm and the evaluation of frequency regulation capability are proposed,based on the minimum inertia demand of the system,combined with the real-time operating conditions of the wind farm.Combined with the frequency regulation characteristics of thermal power units and considering the advantages of flexibility and plasticity of wind power frequency regulation control,the cooperative primary frequency regulation framework of wind farm and thermal power units is constructed,and the cooperative frequency regulation strategy of wind power and thermal power is studied.3.It proposes the use of the dispatching layer to realize the wind-fire cooperative frequency regulation strategy.The dispatching center investigates the optimal allocation of frequency regulation power between wind farms and thermal power plants in the system according to the active disturbance fault characteristics of the system and the operating conditions of wind turbines and wind farms,combined with the minimum inertia demands of the system.Based on a typical 36-node example,a large-scale regional power system frequency regulation model including wind power and thermal power is built to verify the effectiveness and feasibility of the proposed frequency regulation scheme and strategy.The simulation results show that the wind-fire cooperation combined with primary frequency regulation can effectively improve the frequency response capability of the power system and provide a theoretical basis for the operation of a high proportion of new energy power systems.