Coupling Effects of Electric and Flow Fields on The Conductivity of Insulating Oil

The change of mineral oil conductivity affects the design of the electric field inside the converter transformer and seriously threatens the safe operation of the DC transmission system. For this reason, this paper builds the oil flow conductivity platform, carries on the simulation research to the internal power plant of the converter transformer, carries on the different electric field intensity and the flow velocity to the conductivity influence experiment, and analyzes the mineral oil electric conductivity change mechanism through the dissociation compound, the electrode injection, the oil flow electrification theory. The results show that the conductivity of mineral oil shows a U-shaped curve with the change of electric field strength, and decreases first and then increases with the increase of electric field strength; the conductivity of mineral oil has a positive correlation with the flow rate.