Diagnóstico de generadores eléctricos de potencia con técnicas de monitoreo en línea y fuera de línea

Abstract

This paper presents the dielectric analysis of the stator insulation system of four 25 MW generators in a Geothermal Plant in Mexico. Since the first maintenance procedures white powder was detected on the stator windings, indicating that there were high partial discharges. Partial discharges Erode the insulation system and eventually lead to failure. It was decided to investigate both the origins and the level of involvement of the insulation system to make maintenance actions. The evaluation was conducted in two stages. The first step consisted of on-line monitoring of partial discharges and the second step involved offline tests. The first step allowed establishing an initial classification of the machine with the least favorable dielectric conditions. In the second step, the mechanisms of deterioration of the windings were identified and corrective maintenance actions were applied. These actions provided reliability and availability of the four generators.