Detection of Rotor Faults in Synchronous Generators

Abstract

Synchronous generators are subject to a variety of failures which may occur in various parts of their structure. Furthermore, these faults may be categorized as partial failure or catastrophic faults. One may note that most partial faults can eventually result in a permanent lack of service. The present digest deals with a class of failures which may happen in the rotor of a turbo-generator. These faults include electrical failures in the Held n inding and mechanical faults in the form of dynamic eccentricity. Since the electromechanical conversion of energy is closely related to magnetic response of the machine any alteration of the excitation and geometry will result in detectable changes in stator quantities such as no-load voltage. The present digest is based on a detailed analysis of the electromagnetic response of a two pole turbo generator under various types of rotor faults. In the first step existence of detectable time-domain signatures have been investigated. Next, uniqueness of these signatures is studied. In the last part, a systematic method for just-in-time detection and classification of various rotor faults has been developed. Finite element analysis has been used for this study.