Assessing hydrogen direct cooling electrical generators through on-line partial discharge measurements

There are 22 direct cooled hydrogen generators operating in the Mexican Grid. Some of them have experienced outages due to critical failures. A brief description of the cooling system and the deterioration mechanisms is being reviewed in this article. Discharge measurements can be use to accurately determine the conditions of these generators. Partial Discharge activity can be recorded with the generator off-line during maintenance outages at different test voltages levels or on-line with the machine at different load conditions. The obtained results on a 346 MVA, 20 kV generator are reported. Measurements were taking on-line through the RTD's connection box.