Efficient extraction method of friction fault characteristics in vibration signal of rotating shaft

Abstract

The invention discloses an efficient extraction method of friction fault characteristics in a vibration signal of a rotating shaft, comprising the following steps of: selecting a plurality of monitoring sections along the direction of the rotating shaft; mounting an eddy-current transducer to monitor the vibration signal (t) of the rotating shaft; carrying out two times of differential continuously on time by virtue of the actually-monitored vibration signal and carrying out burr point enhancement operation on the signal processed by the two times of differential to obtain Z(t); calculating statistic characteristics of the Z(t) signal to obtain a sample average, a sample variance and a signal Z'(t) without an average value; calculating a signal distortion amplitude fault degree coefficient and a distortion frequency rate fault degree coefficient; calculating average values of the signal distortion amplitude fault degree coefficients and the distortion frequency rate fault degree coefficients in a plurality of periods, and taking the maximum value umax in the two average values as friction fault degree coefficients to judge the friction fault degree; and judging a friction position according to the friction fault degree coefficient of each measuring point of the rotating shaft. The method disclosed by the invention can effectively amplify the early-period friction fault characteristics and improve the diagnosis accuracy of early-period friction faults.

Description

technical field The invention relates to a method for extracting frictional fault features from vibration signals of a rotating shaft. Background technique In order to prevent the leakage of steam, compressed air, lubricating oil and other working media, steam turbines, generators, gas turbines, compressors, pumps, fans and other rotating machinery are equipped with various seals on both sides of the shaft, blade tips and bearings. The gap between parts is small, and friction between moving and static parts is easy to occur during operation. After the friction fault occurs, the vibration of the unit will increase, which will affect the safe and stable operation of the unit. In severe cases, it will lead to serious accidents such as large shaft bending and bearing bush fragmentation. According to incomplete statistics, more than 70% of the bending accidents of turbogenerator sets in domestic power systems are caused by friction failures. Efficient monitoring, analysis and d...