电力系统次同步振荡对风力发电机轴系疲劳损伤影响的可靠性分析

FATIGUE RELIABILITY ANALYSIS OF WIND TURBINES SHAFTS CAUSED BY SUB-SYNCHRONOUS OSCILLATIONS DURING POWER SYSTEM FAULTS

为了分析电力系统发生次同步振荡时对双馈风力发电机轴系疲劳损伤程度的影响,根据2 MW级双馈风力发电机轴系机械结构,运用三质块等效数学模型,通过PSCAD软件仿真得到电力系统发生次同步振荡时风力发电机的电磁扭矩。基于雨流计数法按照电磁扭矩振荡模型制作等效载荷谱。利用Solid Works软件建立风力发电机轴系变速齿轮有限元模型,并用ANSYS软件对其模型进行网格划分与静强度分析。基于S-N曲线理论与Miner线性疲劳累积损伤方法,通过Ncode软件计算风力发电机轴系齿轮在次同步振荡扭振载荷作用下的疲劳损伤程度。分析不同次同步振荡时长对风力发电机轴系齿轮部分疲劳损伤程度的影响。分析结果有助于预测风力发电机轴系齿轮部分使用寿命,提高风电系统安全可靠性。

Fatigue and destruction in the shafts of a wind turbine caused by sub-synchronous oscillations during power system faults is critical for wind turbine reliability. This paper investigates a three-mass shaft model according to a MW class doubly fed wind generator shaft mechanical structure and obtains the electromagnetic torque of wind turbine by PSCAD simulation when sub-synchronousoscillation occurred in power system. The equivalent load spectrum is obtainedvia the rain flow counting method. The finite element model of gear is set up by Solidworks software. And then it is meshed by ANSYS software and finally the equivalent von-Mises stress is got. The fatigue damage oftransmission gear caused by sub-synchronous vibrationloads could be accessed through Ncode software based on the S-N theory theory, then carries on the analysis of reliability. To sum up, the paper provided is an analysis of the fatigue and Miner damage of wind turbines shafts caused by sub-synchronous oscillations of various durations during power system faults. The results are helpful to predict the fatigue life of wind turbine gear, to better maintain wind turbine shafts in time and to improve the safety and reliability of wind power system.