基于非线性动力学的水电机组操作油管振动故障研究

Research on vibration faults of operation oil tubing in hydropower units based on nonlinear dynamics

贯流式机组操作油管与受油器浮动瓦碰摩现象会引起操作油管的异常振动,导致漏油、窜油现象,为更好地保证水电机组的安全运行,在考虑水电机组运行过程中常见频发性故障的情况下,建立包含定转子电磁激励影响和操作油管不对中故障的操作油管-转子振动碰摩的动力学模型及微分方程,采用数值积分法对操作油管径向振动随油管不对中量、励磁电流大小和定子刚度系数等参数变化的非线性动力学特征进行分析,使用时域波形图、频谱、轴心轨迹图、庞加莱截面图和分岔图等多种手段表征系统耦合故障下的动力学响应,发现碰撞摩擦、不平衡磁拉力等因素对机组振动的影响较大,相关研究可为工程实际中多故障源激励耦合造成机组异常运行、停机等现象提供耦合故障类型诊断思路。

The frictions between operation oil tubing of the cross-flow unit and floating tile of the oil receiver can cause abnormal vibration of the operating oil tubing,resulting in oil leakage and channeling.To better ensure safe operation of hydropower unit,this paper develops a dynamic model and differential equation of operation oil tubing-rotor vibration friction including the influence of electromagnetic excitation of stator and rotor and the faults of operating oil tubing misalignment under the condition of common frequent faults in the operation of hydropower units.Numerical integration method is applied to analyze the nonlinear dynamic features of radial vibration of operating tubing with the change of tubing misalignment,excitation current,stator stiffness coefficient and other parameters.The dynamic response of the system under coupling faults is characterized by time domain waveform diagram,spectral diagram,axis center trajectory diagram,Poincare surface of section diagram and bifurcation diagram.It is found that the factors such as collision friction and unbalanced magnetic pull have great influence on the vibration of the unit.This research can provide reference for coupling fault type diagnosis of the abnormal operation and shutdown of the unit caused by coupling of multiple fault sources in engineering practice.