Summary
This paper presents a comprehensive assessment of the electrical insulation condition of the stator windings of a large hydrogenerator rated at 350 MVA. An increase in partial discharge
Read more Read less(PD) levels was identified during on-line monitoring, triggering a detailed diagnostic investigation. Several electrical tests were performed, including on-line partial discharge measurements, insulation resistance and polarization index tests, polarization and depolarization current analysis, capacitance and dielectric dissipation factor measurements, and sweep frequency response analysis. The results indicated localized insulation deterioration, which was subsequently confirmed by visual inspection as a mechanical deformation and overheating of a circular busbar conductor. Corrective maintenance was carried out, followed by a new series of electrical tests, which demonstrated a significant reduction in partial discharge levels and the restoration of normal operating conditions. The study highlights the importance of combining electrical diagnostic techniques with visual inspection for effective asset management of large rotating machines.
Additional informations
| Publication type | Session Materials |
|---|---|
| Reference | A1_10789_2026 |
| Publication year | |
| Publisher | CIGRE |
| Country | Brazil |
| Study committees | |
| File size | 711 KB |
| Price for non member | 30 € |
| Price for member | 30 € |
Authors
NASCIMENTO Júlio - Eletrobras Eletronorte Brazil; BRASIL Fernado - Eletrobras Eletronorte Brazil
Keywords
Stator insulation, partial discharge, SFRA, hydro generator diagnostics
