Research On Intersectional Characteristic And Diagnosis Method Of Generator Winding And Eccentric Fault

Firstly, the electric characteristics of electric fault, such as rotor winding inter-turn short circuit faultand stator winding inter-turn short circuit fault, and the vibration characteristics of machinery fault such asair-gap eccentric fault are analyzed. Then the vibration characteristics of electric fault and the electriccharacteristics of machinery fault(named as intersectional characteristic of fault) are ulteriorly studied.Finally, the automatically identifying method of fault characteristic, adaptive artificial neural networkalgorithm, and fault diagnosis method based on intersectional characteristics are proposed respectively, andfault diagnosis system based on virtual instrument is developed successfully. The main research content inthis paper is following:1. The vibration and electric characteristics of stator and rotor winding inter-turn short circuit fault areanalyzed based on theory and experiment, and the electric characteristics include the stator winding parallelbranch circulating current characteristic and excitation current harmonics characteristic, and the vibrationcharacteristics include stator and rotor radial vibration characteristic and the effect of short circuit positionon vibration feature. After analyzing and comparing the stator and rotor radial vibration characteristic ofrotor winding inter-turn short circuit fault and rotor imbalance fault, a new rotor fault diagnosis methodbased on stator and rotor vibration characteristics is presented, which can distinguish between rotorwinding inter-turn short circuit fault and imbalance fault effectively.2. The vibration and electric characteristics of air-gap eccentric fault are analyzed based on theory andexperiment. Through analyzing the characteristic of air-gap magnetic field, the results show that air-gapstatic eccentric fault will excite stator and rotor vibrate in second mechanical frequency, and air-gapdynamic eccentric fault will excite rotor vibrate in first mechanical frequency, and stator vibrate in first,second, third, fourthly mechanical frequency. Through analyzing the electromotive force difference andcirculating current expressions, the results show fundamental circulating current will increased when thefault has happened. Then comparing the differences among rotor winding inter-turn short circuit, rotorimbalance, air-gap static eccentric and air-gap dynamic eccentric fault, the generator fault diagnosis methodbased on rotor vibration and circulating current characteristics is developed.3. The influence on rotor axis orbit of rotor winding inter-turn short circuit fault is analyzed based onexperiment, the results show that eletric fault is the same as mechanical fault, can causes the change of axisorbit. And a new method for automatically identifying the axis orbit moving direction is presented based oncomputer graphics analysis method, the simulation and experiment results show the method is effective.4. A new adaptive BP network algorithm named as the error contracting gradually algorithm and a newadaptive radial basis function neural network (RBFNN) algorithm named as two levels iteration clusteralgorithm are put forward, which are applied to the generator fault diagnosis system.5. The diagnosis system of generator winding and eccentric fault based on virtual instrument isdeveloped successfully, which is applied to SDF-9 generator.