Frequency Domain Methods for Detection of Rotor Faults in Synchronous Machines under No-Load Condition

Reliable and efficient generation of electricity is of paramount importance in an advanced electric power network. Whether in large synchronous generators that are installed in power plants or for distributed generators in wind farms, survivable performance of these electric machines plays a vital role in accomplishing this goal. The worldwide economical impact of achieving a reliable generation is immeasurable. As a result real time monitoring and just-in-time maintenance of synchronous generators deserves due attention. The present paper deals with this outstanding issue. Synchronous generators are subject to a variety of failures which may occur in various parts of their structure. The present paper deals with a class of failures which may happen in the rotor of a turbo-generator. 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 voltage and current. The present paper is based on a detailed finite element analysis (FEA) of the electromagnetic response of a two pole synchronous 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. Accordingly, a systematic method for just-in-time detection and classification of various rotor faults has been developed.