Turbine-generator condition assessment using Electromagnetic Interference (EMI) testing

Condition assessment of electric machinery has always been a challenge. Even with the best of monitoring, inspection and test, major uncertainties remain relative to remaining reliable life of a generator. On-line monitoring is particularly deficient. Other than load conditions of volts, currents, etc., there are few standard monitoring instruments: slot resistance temperature detectors (which give only a rough idea of what the copper temperatures might be), cooling gas temperatures, field ground, stator current differentials and winding grounds. Specialized devices can be added to improve capability somewhat: generator condition monitor, flux probe for field turn shorts, partial discharge (PD) instrumentation, and stator endwinding vibration instrumentation.