机-网耦合作用下风力发电机传动系统故障机理与诊断方法研究

Wind power is a complex system, including turbine, generator and grid. Focus on the doubly-fed induction generator wind turbine, the integrated model of wind turbine drivetrain-generator-grid with wind load and electromagnetic torque exciting is founded. Coupling mechanism between wind turbine drivetrain and grid is provided by analyzing on dynamic and damage characteristics of drivetrain under the grid impact，and the reaction of drivetrain to grid. The dynamic characteristics and fatigue life evaluation model of drivetrain are proposed under dual varying loads, including wind load and electromagnetic torque. Based on the effect mechanism of drivetrain fault to the generator and grid, drivetrain fault features of vibration, torque and current are discussed. The advantage of vibration signal is fault sensitivity, torque and current are anti-interference, thus The electrical-mechanical combined feature fault diagnosis method proposed by combining the advantages of the three parameters. Theoretical model associating experiment method is adopted to study multidisciplinary intercrossing, including machinery system dynamics, fault diagnosis technique, aerodynamics and power system stability involved in the proposal. New theoretical basis is supplied for the wind turbine safety foundation science.

风力发电系统是包含了机、电、网的复杂系统，课题以双馈风力发电机组为对象，建立风载-电磁转矩双激励下风力发电机传动系统-发电机-电网统一模型，研究电网冲击下风力发电机传动系统动力学特性变化规律及损伤特性，分析传动系统对发电机、电网的反作用特征，得到机-网耦合作用机理。建立风载、电磁振荡转矩双变载荷风力发电机传动系统疲劳寿命评估模型。研究传动系统故障对发电机、电网的作用机理，分析传动系统故障下振动、转矩、电流等参数的诊断特征，结合振动信号对故障的敏感性，转矩、电流信号不易受干扰的优点，提出基于振动、转矩、电流机-电联合特征的风力发电机传动系统故障诊断方法。课题采用理论建模与实验研究相结合的方式，涉及机械系统动力学、故障诊断技术、空气动力学、电力系统稳定等多学科交叉问题，为风电机组安全运行的基础科学研究提供新的理论依据。

以1.5MW实际机组参数建立了包括机械传动系统、发电机及控制系统及电网等部分的双馈风力发电机组机-电-网模型。通过模拟电网故障，分析了不同程度电压跌落条件下风力发电机有功功率和无功功率、电磁转矩、机械转矩及转速等的响应变化，得到了风力发电机传动系统机电耦合作用过程，分析总结了传动系统参数变化对机电系统振荡响应的基本影响规律。采用风力发电机齿轮传动系统非线性动力学模型，得到了考虑风速随机性、综合合啮合误差、啮合阻尼、齿侧间隙、支承刚度等因素变化下风力机传动系统动力学行为变化特征。利用数据采集与监控系统的多源数据信息，采用概率权重法给出了风力发电机运行数据之间的相关特性曲线，基于平均相关性指标实现了相关参数的量化分析方法，提出了基于组合模型残差和近似熵风电机组状态异常评估方法。研究了风力发电机传动系统早期故障特征，提出了基于概率主成分分析的滚动轴承早期故障诊断方法。研究了数学形态方法对振动信号的处理特性，提出了基于数学形态的早期故障特征提取方法。研究了风力发电机传动系统复合故障的响应及耦合特性，给出了部分重叠共振频带的多故障信号仿真模型，提出了相关峭度共振解调、自适应最大相关峭度解卷积的复合故障特征提取及分离方法。项目成果对于风力发电机传动系统设计与控制优化、安全可靠运行、提升风电场运维水平具有重要的理论和现实意义。