Effect of Electric Field on Conductivity of Synthetic Ester

Synthetic ester has emerged as an environmentally friendly alternative to mineral oil for power transformers and is being considered as a potential replacement for mineral oil in HVDC converter transformers. However, the conductivity of insulation is a crucial parameter in the design of HVDC transformers, and there has been little research on the conductivity of esters compared to mineral oil. This paper investigates the impact of electric field on the conductivity of a synthetic ester. The results indicate that the conductivity of the synthetic ester was generally higher than that of conventional mineral oil. A positive correlation was observed between short-term conductivity and the electric field, while long-term conductivity exhibited a non-linear trend. The increase in short-term conductivity with the increase in electric field was found to be primarily due to the field-enhanced charge dissociation.