Research On Frequency Regulation Control Strategy Of Wind Turbine Based On Standby Capacity

In the 21 st century with the rapid development of wind power technology,doubly-fed wind turbine,as the mainstream product of wind power,can not only operate at variable speed and constant frequency,but also has the advantage of high utilization rate of wind energy,so it is more and more favored by people.Because the rotor speed of wind turbine is decoupling from the frequency of power grid,it does not participate in the primary frequency regulation of power grid.When more and more doubly-fed wind turbines are connected to the grid without participating in primary frequency regulation,the frequency regulation pressure of conventional turbine will be increased.In this paper,the primary frequency regulation control strategy suitable for doubly-fed wind turbine is studied.The main work is as follows:In order to solve the problem that the doubly-fed wind turbine does not reserve enough frequency regulation reserve capacity,the rotor dynamic energy control and power standby control are studied,and the primary frequency regulation segmented control strategy of wind turbine is put forward.In this strategy,the load reduction operation of wind turbine is realized by over speed control and pitch angle control,and the wind speed is divided into three intervals.According to the operation characteristics of the turbine under different wind speed,different control strategies are designed.So that the wind turbine can dynamically adjust the load reduction coefficient under different wind speed,which not only ensures that the wind turbine reserves enough reserve capacity to participate in frequency regulation,but also reduces the influence on power generation.In order to solve the problem of torsional vibration of shafting caused by frequency change of wind turbine participating in primary frequency regulation,based on the mathematical model of shafting of wind turbine,the cause of torsional vibration of shafting is analyzed,and the damping controller of shafting is designed.The dynamic adjustment method of shafting damping controller parameters is designed by using fuzzy control,so as to reduce the amplitude of torsional vibration and the damage to wind turbine caused by torsional vibration of shafting.In order to verify the effectiveness of the proposed control strategy,a model of four-machine and two-area power grid is established in PSCAD/EMTDC simulation software.The frequency fluctuation of the power grid is simulated by changing the load,and the simulation is carried out under this condition.The simulation results show that the primary frequency regulation segmented control strategy proposed in this paper can reserve a certain amount of frequency regulation reserve capacity under different wind speeds,and has little effect on power generation.The dynamic adjustment method of shafting damping controller parameters proposed in this paper can ensure that wind turbines can effectively participate in the primary frequency regulation of power grid and reduce the torsional vibration of shafting caused by primary frequency regulation.