低电压穿越过程中风电机组载荷特性联合仿真研究

Joint Simulation Study on Load Characteristics of Wind Turbines in Low Voltage Ride Through Process

【目的】电网电压跌落故障会引起风电机组载荷的剧烈变化,严重影响风电机组的安全稳定运行。随着风电机组的大型化,风电叶片长度不断增加,塔筒增高,其载荷特性对系统参数波动变得敏感。因此,需要研究电网电压跌落过程中关键部件的载荷与振动特性。【方法】提出了基于动态链接库和Socket通信的数据交互方式,建立了Simulink与Bladed的联合仿真方法。基于某3.4 MW风电机组模型,采用给定风速变化的工况对联合仿真平台进行验证。研究了低电压穿越(low voltage ride through,LVRT)过程中机组总体性能与叶片、塔筒载荷的变化关系。【结果】电网电压跌落幅值对电机功率影响较大,对风轮的调节参数影响较小。低电压穿越过程中风轮的桨矩角调节和转速有较长时间的波动,叶片外叶展处载荷的变化大于内叶展处,叶尖位移增加。塔架的振动频率与固有频率接近,存在潜在风险,需要在机组设计中考虑。【结论】联合仿真平台可以很好地模拟风电机组的气动性能与部件载荷的暂态特性,为机组的优化控制提供参考。

[Objective]The grid fault of voltage drop will cause severe variations to the load of wind turbines,and seriously affect the safe and stable operation of wind turbines.With the increasing of the wind turbine scale,the blade length and the tower height increase continually,leading to the increase of the sensitivity of load characteristics to the system parameter fluctuations.Therefore,it is necessary to study the load and vibration characteristics of key components in the process of grid voltage drop.[Methods]A data interaction method based on dynamic link library and Socket communication was proposed,and a joint simulation method of Simulink and Bladed was established.Firstly,based on a 3.4 MW wind turbine model,the joint simulation platform was verified by a given wind speed variation condition.Then,the relationship between the overall performance of the unit and the load of the blade and tower during low voltage ride through(LVRT)was studied.[Results]The amplitude of grid voltage drop has a great impact on the generator power,and has little impact on the wind turbine control parameters.In the process of LVRT,the blade pitch angle and rotational speed of the wind turbine fluctuate for a long time,the load change at the outer blade span is greater than that at the inner blade span,the blade tip displacement increases,and the vibration frequency of the tower is close to the natural frequency.These potential risks should be considered in wind turbine design.[Conclusion]The joint simulation platform can effectively simulate the aerodynamic performance of the wind turbines and the transient characteristics of the component loads,and provide a reference for the optimal control of the unit.