Electric Power Components and Systems, 43(20):2262–2275, 2015 CopyrightCTaylor & Francis Group, LLC
ISSN: 1532-5008 print / 1532-5016 online DOI: 10.1080/15325008.2015.1082161
Fault Diagnosis of an Induction Generator in a Wind Energy Conversion System Using Signal Processing Techniques
Issam Attoui
1and Amar Omeiri
21Research Center in Industrial Technologies CRTI, Cheraga, Algeria
2Laboratory of Electrical Engineering Annaba (Laboratoire d’ ´Electrotechnique [LEA]), Badji Mokhtar-Annaba University, Annaba, Algeria
CONTENTS 1. Introduction
2. Modeling of the System
3. Electrical Fault-Related Components 4. Review of Conventional STFT and DWT 5. Implemented Diagnosis Procedure 6. Results and Discussions
7. Conclusion References Appendix A Appendix B
Keywords: wind energy conversion systems, induction generator, signal possessing, fault severity factor, faults classification, fault detection and diagnosis
Received 4 November 2013; accepted 26 July 2015
Address correspondence to Dr. Issam Attoui, Research Unit in Advanced Materials, Research Center in Industrial Technologies CRTI, P.O.Box 64, Cheraga, Algeria. E-mail: atoui article@yahoo.fr
Abstract—In this article, a contribution to fault diagnosis of an in- duction machine in a wind energy conversion system in closed-loop operation using a combination between short-time Fourier transform and discrete wavelet transform algorithms is proposed. An on-line fault diagnostic technique based on stator currents analysis of the squirrel-cage induction generator is proposed to detect and localize abnormal electrical conditions that indicate, or may lead to, a stator or rotor failure in a squirrel-cage induction generator. This technique also permits identification of a fault severity factor and consequently helps to determine the best choice of corrective maintenance. Further- more, a generalized model of the squirrel-cage induction generator is used to simulate both the rotor and stator faults, taking iron losses, main flux, and cross-flux saturation into account. The efficiency of diagnostic procedure in closed-loop operation of the wind energy conversion system under non-stationary operating conditions is illus- trated with simulation results.
1. INTRODUCTION
Over the past few years, the fault-diagnosis methods of elec- trical machines, such as the doubly fed induction machine (DFIM), squirrel-cage induction machine [1, 2], and the per- manent magnet synchronous machine (PMSM) [3, 4], have been the subject of increased attention. These electrical ma- chines can be used in almost all types of renewable energy applications [5–8]. These systems can be subjected to the un- avoidable stresses, such as electrical, environmental, mechan- ical, and thermal stresses, which create failures in their differ- ent parts [9]. In such applications, the induction machines that operate in the self-excited mode for stand-alone applications have become popular in view of their advantages over other types of machines [10, 11]. Cost-effective and reliable mainte- nance of these machines is thus needed to reduce the mainte- nance expenses by preventing high-cost failures and unsched- uled downtimes. In the other hand, the control of the terminal 2262
