Analisis Sifat Isolasi dari Campuran Metil Ester Rice Bran Oil dan Minyak Mineral dengan Penambahan Al2O3 sebagai Alternatif Isolasi Cair Transformator Daya

Abstract

Continuous use of mineral oil that cannot be renewed without preparing alternative oils could become a problem in the future. Vegetable oil alternatives do not guarantee the suitability of their use in the long term because they can rot when undergoing an oxidation process. For this reason, research was carried out by changing vegetable oil into methyl ester first before mixing it with mineral oil. The research was conducted by mixing Rice Bran Oil Methyl Ester and Shell Diala B Mineral Oil with the addition of Al₂O₃, then testing its insulating properties. The results showed that RBO had lower viscosity, dielectric strength, and resistivity but higher density than Shell Diala B oil. The addition of Al₂O₃ reduced the dielectric strength and viscosity, and increased the breakdown voltage and decreased the viscosity as the percentage of RBO in the mixture increased. Resistivity decreased with increasing temperature, with Shell Diala B oil showing higher resistivity than RBO. The addition of Al₂O₃ helped maintain resistivity at a higher level and stabilized the density. The mixing of Al₂O₃ in the combination of RBO and Shell Diala B oil can improve the quality of liquid insulation, making it a potential alternative for transformer applications. The percentage composition of the mixture of RBO methyl ester and mineral oil with the addition of Al₂O₃ which has the best density value is sample S3 with a density value of 0.801 g/cm3 and the best viscosity value is sample S4 with a viscosity value of 2.56 cSt which has met the ASTM No. D 1298 and ASTM No. D 445 standards. While for the best dielectric strength and resistivity values, respectively, are sample S3 with a value of 31.6 kV/2.5 mm which has met the ASTM No. D 887 standard and 0.241 GΩm for a temperature of 20℃ and 0.086 GΩm for a temperature of 90℃ has met the IEC 60422-2013 standard