水电机组摆度周期性波动问题的分析和研究

Analysis and Research on the Cyclical Fluctuation of Swing in Hydro-generator Set

本文针对某水电站机组上导轴承摆度峰峰值持续呈正弦周期性波动的问题,通过增加临时探头测量机组动态和静态时上机架支臂和基坑的间隙,以及不同方向支臂的间隙和机组运行参数等,发现支臂和基坑间隙一一对应,且间隙随环境温度的增加而增加,该间隙的变化规律符合因大部件金属构件蠕变传递至基座传感器引起的上导摆度周期波动的特征。因此可以确定机组摆度周期性波动是因为大部件金属随着温度变化而出现较大的位移蠕变,且该蠕变为非对称蠕变,以上过程量逐级传递至基座传感器位置,同时该文建议采用该结构形式的机架时应充分考虑支臂蠕变方向和限位措施。

This paper deals with the problem that the peak-to-peak value of the swing of upper guiding shaft continuous change of a hydropower station continuously fluctuates sinusoidal periodicity,the temporary eddy current probe is added to measure the clearance between the upper frame arms and the foundation pit in dynamic and static state of the unit,as well as the clearance between the frame arms and the foundation pit in different directions and the operating parameters of the unit.It is found that the clearance between the upper frame arm and the foundation pit corresponds one by one and the clearance increases with the increase of ambient temperature.The change law of the clearance is consistent with the periodic fluctuation of the upper leading pendulum caused by the creep of the metal component of the large component to the sensor base.Therefore,it can be concluded that the periodic fluctuation of the swing of the unit is due to the large displacement creep of the large component metal with the change of temperature,and the creep is asymmetric creep.The above process quantities are transmitted to the position of the base sensor step by step.At the same time,it is suggested that the creep direction and limiting measures should be taken into full consideration for the frame with the structure.