Evaluation Of Frequency Regulation Capability Of Wind Turbine From The Perspective Of Energy

Under the dual promotion of technology and policy,the proportion of wind turbines is gradually increasing.The large-scale grid connection of wind turbines reduces the equivalent inertia of the system and reduces the power reserve capacity,resulting in a decrease of the system frequency regulation capability;at the same time,the inherent volatility and randomness of wind turbine output makes the system frequency regulation capability change from time to time,which has a great impact on the grid frequency regulation and seriously threatens the system frequency stability.In this context,the evaluation of the frequency regulation capability of wind turbines has become an unavoidable hurdle in the study of system frequency stability.In this paper,the frequency regulation capability of wind turbines is evaluated from two perspectives,rotor kinetic energy and power reserve,respectively,from an energy perspective,and the specific research work is as follows.To evaluate the frequency regulation capability of wind turbines from the perspective of rotor kinetic energy,based on the principle of zonal operation of wind turbines,the release of rotor kinetic energy in the maximum power tracking zone and the constant speed zone are studied separately;in the specific research process,according to the role of rotor kinetic energy during frequency regulation,it is divided into two parts,one part is to compensate for the loss of captured wind energy due to frequency regulation,and the other part is to play a role in the frequency response.On this basis,the effect of wind speed and frequency regulation parameters on the release of rotor kinetic energy is analyzed in detail under stepwise frequency regulation,and the mechanism of their interaction is revealed,and the boundary range between the factors affecting the release of rotor kinetic energy is clarified under the maximum release of rotor kinetic energy,so as to realize the visualization of the wind turbine’s frequency regulation capability.The simulation results show that the classification of rotor kinetic energy in this paper is consistent with the actual situation,and the actual frequency regulation energy can reflect the frequency regulation capability of the generator to a certain extent,and the theoretical analysis of rotor kinetic energy is scientific and reasonable.In evaluating the frequency regulation capability of wind turbines from the perspective of power reserve,the wind turbine’s frequency regulation capability is firstly divided into the power-up capability and power-down capability according to whether the turbine increases or decreases its output during the frequency regulation period,and the upgrade reserve capacity and lower reserve capacity are used to evaluate them respectively.In evaluating the power-up capability of wind turbines,an upgrade reserve capacity evaluation method is proposed based on the wind speed and wind direction data measured by anemometer towers considering the influence of wake effect,terrain undulation and unit start-stop factors on the evaluation results,and in evaluating the power-down capability of wind turbines,a phased lower reserve capacity evaluation method is proposed based on the difference of rotor overspeed control and pitch angle control response speed,which divides the lower regulation reserve into fast down regulation reserve and slow down regulation reserve.The evaluation is carried out separately.Finally,the proposed method is validated by simulation experiments,and the results show that the proposed method can accurately evaluate the wind farm upgrade reserve capacity even in wind farms with frequent wind direction changes and rugged terrain,and can objectively reflect the frequency regulation capability of wind turbines.