Abstract. Condition-based maintenance for turbine generators (TG) experience is given in the paper. Defects in stator winding and in magnet core are determined before repair on the basis of double-coordinate on-line discharge events location. Full information about ground wall semiconductivity layer in bars, slot discharges, sparking between plates in magnet core are provided by generators operating load from Wmin to Wmax measurements.

The defect diagnostics affirmed the forecasted failures

Migrating iron particles were detected through location and were fixed protractedly in service installed (without shut down) continuum monitoring system for turbine generator.

Sparking in core.

Partial discharges.

Slot discharges.

Double locations after repair of turbine generators by operating load variation affirmed defect absence, which is the quality of repair work.