Monitoring of the dielectric dissipation factor during oil reconditioning process for transformer drying

VERUCCHI, CARLOS J.; MEIRA, MATIAS; MAYORA, HERNÁN; ÁLVAREZ, RAÚL E.

Denver

Congreso; 2021 Electrical Insulation Conference (EIC); 2021

In this work, the dielectric dissipation factor testis proposed for determining the duration of reconditioningprocess for transformer drying out. For this purpose, a casestudy of a three-phase rectifier power transformer with highmoisture content in the solid insulation, in which the drying outprocess was carried out, is presented. The original oil wasreplaced with new oil, and this new oil is used as the mediumfor drying out the cellulose through a recirculation process.Thus, in this procedure, the oil reconditioning process isrequired. The resistivity, breakdown voltage, and watercontent are also monitored during the reconditioning of the oil.The results show that this strategy improves the efficiency ofthe reconditioning of the solid insulation process, mainly byreducing processing times where the modifications in the oilproperties do not change significantly. The results arevalidated with dielectric frequency response analysis.