DC Breakdown Properties and Mobility Characteristics of Different Insulation Liquids Applying in Transformer

Transformer is a key component in power grid, and oil is still used widely as main insulating and cooling media because of its excellent property. Nowadays different kinds of oil get a lot of applications, including mineral oil, synthetic ester and natural ester, etc. HVDC systems and equipment require concrete information about dielectric property of insulating fluids under dc excitation. Therefore, it is vital to study the dielectric properties of dielectric liquids, and to understand their behaviour under both types of excitation. In this paper, DC breakdown voltage and apparent mobility of three kinds of oils were measured, and these results could give some reference to substitute traditional mineral oil in transformer.