A Hybrid Method to Diagnose 3D Rotor Eccentricity Faults in Synchronous Generators Based on ALIF_PE and KFCM

Chao Zhang,Lun Cheng,Shuai Li,Chuang-Jin He,Yu-Ling He,Xiang-Yu Liu,Xiao-Long Wang,Francisco Beltran-Carbajal

doi:10.1155/2021/5513881

Abstract

This paper proposed a new hybrid diagnosis method for the generator’s 3D static eccentricity faults which include the axial eccentricity, the radial eccentricity, and the mixed eccentricity composed of the former two. Firstly, adaptive local iterative filtering (ALIF) method was used to decompose the vibration signals of the generator under eccentricity faults. Then, in order to figure out the intrinsic mode function (IMF) components with the upmost feature information, the correlation coefficient was calculated. Finally, the components’ permutation entropy (PE) is extracted to construct the eigenvector matrix which can be used to input the kernel fuzzy C-means (KFCM) algorithm to obtain the result of clustering. The result indicates that the classification coefficient based on ALIF and KFCM behaves closer to 1, while the average fuzzy entropy (FE) is closer to 0, showing that this method is able to detect different eccentricity faults more accurately.

Highlights

As the center of electric system, generator is a typical highspeed rotating machine which is highly potential to suffer different faults such as rotor eccentricity or other mechanical failures from time to time [1, 2]
Some scholars pay attention to the motor current signature analysis; for example, Taner Goktas et al [5] dealt with the discernment of broken magnet and static eccentricity faults through the stator phase current. ey analyzed stator electromotive force and phase current waveforms in detail to identify the discerning components and characterize their dynamic behaviors. e method was verified through both simulations and experiments
Method to Test the Vibration Signal. e experiment is carried out on the CS-5 prototype generator which has one pole-pair and a rated rotation of 3000 rpm, as shown in Figure 8(a). e rotor is kept stable with the foundation by the bearing blocks, while the stator can be moved along the radial direction and axial direction, respectively, to simulate the radial eccentricity, the axial eccentricity, and the mixed eccentricity, as illustrated in Figure 8(b). e movements are performed by 8 screws, with four for the radial and the other four for the axial shifts, and controlled by four dial indicators

Summary

Introduction

As the center of electric system, generator is a typical highspeed rotating machine which is highly potential to suffer different faults such as rotor eccentricity or other mechanical failures from time to time [1, 2]. Some scholars pay attention to the motor current signature analysis; for example, Taner Goktas et al [5] dealt with the discernment of broken magnet and static eccentricity faults through the stator phase current. Attoui and Omeiri [6] proposed a new fractional-order controller (FOC) with a simple and practical design method which can ensure the stability of the nonlinear system in both healthy and faulty conditions. They used an online fault diagnostic technique based on the spectral analysis of stator currents by a fast Fourier transform (FFT) algorithm in order to detect the stator and rotor faults

Methods

Results

Conclusion