A maintenance alarm for alternators based on eigensolutions

Abstract

Important variations in response behaviors of power plant alternators are observed in a population of otherwise nominally identical installations due to numerous and significant sources of variability. Moreover, the complexity of such structures render difficult the design of a reliable physics-based model so that the dynamic behavior is assess among other by the identified eigensolutions when the machine is shutdown. In this article, a maintenance alarm is formulated based on this identified modal basis. The objective is to usefully bound the response in operation based on the identified eigensolutions obtained on the machine alone. However, it is known that thermal and nonlinear mechanical effects of the functioning alternator modify the associated eigenparameters. Since these effects are not well known, an info-gap robustness analysis is performed to investigate the impact of this lack of knowledge on the response levels of interest. The proposed methodology is illustrated both on a simplified numerical model of a stator and on an identified modal basis of an academical structure. © (2012) by the Katholieke Universiteit Leuven Department of Mechanical Engineering All rights reserved.