[IEEE 2009 IEEE 9th International Conference on the Properties and Applications of Dielectric Materials (ICPADM) - Harbin, China (2009.07.19-2009.07.23)] 2009 IEEE 9th International Conference on the Properties and Applications of Dielectric Materials - Unique relationship between interfacial tension test (IFT) and neutral number test (Acidity) of transformer insulation oil in PLN P3B JB - Jakarta and Banten Regional