Comprehensive Broken Damper Bar Fault Detection of Synchronous Generators

Abstract

Reliable operation of synchronous generators in hydroelectric power plants is crucial for avoiding unplanned stoppages that can incur substantial costs. The damper winding of salient pole synchronous generators (SPSGs) contributes to machine operation only during transient periods; however, it is a critical component that preserves the dynamic stability and protects the rotor in case of a fault. Consequently, detection of a broken damper bar (BDB) fault is vital for safe operation. Current methods for the BDB detection depend on visual inspection or offline tests. However, most of the recently proposed approaches have used invasive sensors that can detect BDB faults only during transient operation. In this article, a novel method is proposed based on a noninvasive sensor with high sensitivity to BDB faults that can identify a BDB fault either during transient operation or in the steady-state (SS) period. The effectiveness of the proposed method is validated by finite-element modeling and by experimental results from a 100-kVA custom-made SPSG. The proposed method is confirmed to provide a reliable and sensitive diagnosis of BDB faults during transient or SS operation, even in noisy environments.