Impact of Single and Combined Faults Composed of Rotor Eccentricity and Stator Interturn Short Circuit on Electromagnetic Torque Ripples in Synchronous Generator

Yu-Ling He,Zhi-Jie Zhang,Chris Gerada,Gaurang Vakil,David Gerada,Peng Gao,Xiao-Long Wang

doi:10.1155/2020/8535421

Abstract

In order to comprehensively study and identify the electromagnetic torque (EMT) difference among the single static air-gap eccentricity (SAGE) fault, the single stator interturn short circuit fault (SISC), and the combined fault composed of these two, this article investigates the EMT ripple properties due to the mentioned three faults. Different from other studies, this paper considers not only the effect of the single fault types but also the impact of the single fault combinations on the EMT ripple characteristics. Detailed EMT expressions for each fault are firstly derived on the basis of the magnetic flux density (MFD) analysis. Then, finite element calculation and experimental study on a CS-5 prototype generator with two poles at 3000 rpm, which is specifically designed and manufactured ourselves, are carried out to validate the analysis result. It is found that the three faults will induce different ripple components in EMT. The combined faults have the most intensive impact sensitivity on the EMT ripples, while the single SAGE fault ranks the last in the impact effect.

Highlights

In synchronous generators, the electromagnetic torque (EMT) ripple is a primary parameter for the energy conversion
The EMT ripple characteristics in a synchronous generator caused by the single static air-gap eccentricity (SAGE) fault, the single stator interturn short circuit fault (SISC) fault, and the combined fault composed of SAGE and SISC are analyzed and compared. e novelty of this paper primarily lies in the following three issues
(1) We investigate the EMT ripple properties under the single SAGE fault and the single SISC fault and in the combined fault cases which are rarely taken into account by other studies

Summary

Introduction

The electromagnetic torque (EMT) ripple is a primary parameter for the energy conversion. The EMT properties due to varied faults, especially the combined faults such as the static air-gap eccentricity (SAGE) and stator interturn short circuit (SISC) composite fault, have not been fully studied. For SAGE, scholars have investigated both the mechanical and the electrical faulty properties He et al investigated the unbalanced magnetic pull (UMP) [8], the vibration characteristics of the rotor [9], and the circulating current inside the parallel branches [10]. We proposed a comprehensive study on the impact of the single and the combined faults which are composed by SAGE and SISC on the electromagnetic torque ripples.

Theoretical Analysis Model

FEA and Experiment Validation

A 0 Rf

Conclusions