电网短路故障下双馈风电机组传动链扭振响应

电网故障引起的电磁转矩波动易造成风电机组轴系扭振疲劳损耗,严重时会造成轴系故障,有必要研究不同类型电网故障下风电机组传动链扭振响应及其对关键部件的影响。首先,采用集中质量法,考虑叶片柔性建立了风电机组传动链四质量块模型,基于小信号模型,采用模态分析法对风电机组传动链扭振特性进行分析。其次,为了表征不同故障类型对风电机组传动链轴系扭振的影响,在双馈发电机电磁暂态模型的基础上,推导了电网对称与不对称故障下电磁转矩表达式。最后,基于四质量块传动链模型,仿真分析了单相、两相和三相接地电网故障对机组传动链扭振响应的影响。结果表明,不同类型电网故障会影响不同传动链扭振频率及其不同关键部件;三相接地电网故障引起的传动链扭振幅值大,齿轮箱和发电机转子间轴上传递转矩可以较全面反映扭振响应频率;与传动链其他部件相比,发电机转子受到电网故障影响更大。

Orsional vibration responses of drive train of doubly fed induction generators under grid short circuit faults

Due to grid fault, the fluctuation of electromagnetic torque can lead to the torsional vibration fatigue loss of wind turbine shaft system. In severe cases, it can damage the shaft. It is necessary to investigates the torsional vibration responses of drive chain and its influence on key components under different grid faults. First of all, a four-mass model considering the flexible wind turbine transmission chain is established by using the centralized quality method. The torsional vibration characteristics of the transmission chain of the wind turbine are analyzed by modal analysis. Secondly, in order to characterize the influence of different fault types on the torsional vibration of the drive train shaft of wind turbines, based on the electromagnetic transient model of doubly-fed generator, the expressions of electro-magnetic torque under symmetrical and unsymmetrical faults of the power grid are deduced. Finally, based on the 4-mass transmission chain model, the influences of single-phase, two-phase and three-phase earth fault on the torsional vibration transmission of the transmission chain are simulated and analyzed. The results of show that different kinds of power grid faults will affect the torsional frequency of different transmission chains and different key components. The torsional vibration amplitudes of transmission chains caused by three-phase grounding grid faults are high, and high-speed axis mass Inter-torsional torque can more fully reflect the torsional vibration frequency, and the generator components are more affected by grid faults.