ABSTRACT

ADYGUNA UTINA. Transformer Oil Impurity Effects on the Insulation Strength under Multi-stress Aging (supervised by H. Muhammad Arief and Salama Manjang).

This research investigates the effects of impurity on the physical, chemical and electrical performance of the transformer oil insulation liquid. The insulation is tested under various conditions of multi-stress aging. The impurity analysis on the transformer oil has shown experimentally that the breakdown voltage decreases 2.1 kV/ppm and the temperature increases 1.51oC/kV. The analysis on the oxidation stability using the Badder Test (10 days, 100 oC) has indicated that the increasing operating temperature above 60 oC will cause a decomposition of both the physical property, i.e. the interfacial tension, and the chemical property, i.e. acidity. To improve the performance of the oil under aging condition, it is suggested to purify the oil through the flushing process and recuperation. The usage of transformer oil with high quality electrical properties and resistant to acidity, such as Shell Diala HX and Nytro 10X, will decelerate the aging process due to the containment of an inhibitor agent DBPC (Ditertiary Butil Para Cresol).