Transformer oil regeneration as a panacea for electric power utility company‟s equipment optimization

Abstract

Power transformers constitute the most costly equipment which often posed constraints to electric power utility companies’ management. These transformers develop faults often due to oil insulation problems resulting from poor level of insulation oil, lack of routine maintenance, contamination, age, carbonization arising from system tripping as well as degradation of paper insulation due to ageing. However, the most economical way of maintaining stability in power supply to customers is creating a routine program of transformer oil regeneration for power transformer in the network. This paper therefore presents the optimization process of transformer oil regeneration for electric power utility company equipment. In this study, combined techniques of hot oil circulation, oil purification and oil reclamation of transformer oil regeneration was used for analysis of two 15MVA, 33/11kV power transformer. The process is aimed at drying the solid insulation of the transformer through the circulation of hot oil. The results of the transformer oil test before and after carrying out oil regeneration processes for the two 15MVA transformers are obtained and presented. For each transformer, the results are in five categories of properties namely; Physical, Electrical, Chemical, Dissolved metals and Dissolved gas analysis properties. The results indicated that the viscosity of transformer 1 is better than that of transformer 2. In addition, the dielectric breakdown voltage of oil transformer 1 is of more quality than the oil in transformer 2. The results are in agreement with standard ASTMD, IEC and ISO because the transformer properties has individual standard with each having its own mark. The comparison shows that transformer oil regenerated was very close to reality because the oil in the two power transformers is close to 90 %.