基于Lyapunov指数-相轨迹的发电机组故障诊断

Faults Diagnosis Based on Lyapunov Exponent and Phase Trajectory for a Generator Sets

以混沌理论为基础,根据非线性动力学系统的运动特性,对汽轮发电机组转子故障进行了分析阐述·通过对所测发电机组转子在3种不同工作状态下的时间序列进行的最大Lyapunov指数计算,并结合对这3种状态相轨迹图进行的分析和研究,发现发电机转子在不同工作状态下其时间序列的Lyapunov指数具有明显差异·因此,基于Lyapunov指数的实质,提出了发电机组故障诊断的'Lyapunov指数-相轨迹'法·该研究也为其他复杂机械的故障诊断和预测开辟了有效途径·

Based on chaos theory and the motional characteristics of non-linear dynamical systems, the fault diagnosis to a rotor of turbo-set generator was discussed. Three different running states of the generator rotor were studied in time series to determine the largest Lyapunov exponents from acquired time series, combining with the phase trajectory diagrams analyzed in the three states. The results showed that the largest Lyapunov exponents of time series obtained in the three different running states are different greatly form each other, with the types of the faults of the generator rotor thus revealed. The results were proved by the phase trajectories reconstructed with displacements and velocity shown by the time series data. It means that the largest Lyapunov exponent can be used as a quantified value to judge the motional characteristics of non-linear dynamical systems. So, a new and reliable method called as 'Lyapunov exponent-phase trajectory' is proposed to diagnose and predict the faults of a turbo-generator set or other complex mechanisms.