A Case Study of Fault Diagnosis of Stator Winding of Hydro Generator by On‐Line Partial Discharge Diagnosis

ABSTRACT Stator windings of hydro generators are exposed to combined thermal, voltage, environmental, and mechanical stresses, which deteriorate the insulation performance. On the other hand, various stator faults occur in the stator. The stator faults are accompanied by partial discharges, which may lead to dielectric breakdown depending on the type of faults. This paper presents a case study of detecting stator faults by on‐line partial‐discharge diagnostics. The type of stator faults is identified based on reproducible experiments. Furthermore, the advantages of online partial‐discharge diagnostics compared with offline diagnostic methods in detecting stator windings are discussed.