Signal-Model-Based Fault Diagnosis in Windings of Synchronous Generator

Any reduction in the cross-sectional area of wires (RCSAW) in the stator or rotor (field or damper) windings of synchronous generators (SGs) is considered as a fault in SGs. In this article, a signal-model-based fault detection, isolation, and estimation approach based on the eigenvalues estimation of SGs is presented to diagnose RCSAW fault. The subspace identification method is employed to estimate the state matrix eigenvalues. A form of the characteristic equation in the faulty condition is introduced for fault diagnosis of SGs in the presence of linear and nonlinear loads. The stator and field currents and voltages, and the rotor speed are used for fault diagnosis. The effectiveness of the introduced fault diagnosis method is shown using simulation and experimental results on a salient-pole SG in Iran-Safir (ER24) diesel-electric locomotives.

I. Introduction

Synchronous generators (SGs) are widely used to convert mechanical power to electrical power in the presence of linear or nonlinear loads. Fault diagnosis in SGs is essential for improving reliability, availability, maintainability, and safety. Faults in an SG can result in catastrophic failure of a power system, increase the repairing cost, and heavy financial losses. Faults in SGs are classified into electrical and mechanical faults. Electrical faults include faults in stator and rotor windings, and those in the insulation of a core, stator, and/or rotor [1]–[3].