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 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 paper, a novel method is proposed based on a non-invasive sensor with high sensitivity to BDB faults that can identify a BDB fault either during transient operation or in the steady-state 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 steady-state operation, even in noisy environments.

Advanced Fault Detection of Synchronous Generators Using Stray Magnetic Field

“…Both the detailed specification of the SPSG geometry and the non-linearity of the material are considered in finite element modeling (FEM), since both have a marked impact on the stray flux distribution. The eddy effect in damper bars is also considered since a synchronous machine with a fractional winding layout has a circulating current in the damper bars even during steady-state operation [4]. A 2D FEM model of the SPSGs is adequate since the rotor or damper bars are not skewed.…”

Multi-Parametric Condition Monitoring of Medium-Power Generators with Brushless Exciters under Mechanical Faults

“…In order to make it easier for implementation, a non-intrusive axial and radial flux search coil has been proposed [11]. Alternatively, a non-invasive search coil has been suggested to capture the stray flux at the back side of the stator yoke to detect broken damper bars as well [12]. The magnetic flux monitoring has known tremendous interest and advancement lately, as shown by recent review works [13]- [14].…”