Conductivity of transformer oil under high-frequency voltage

Proper treatment of insulating liquid will result in improvment of properties of the whole insulating media of power transformers. High-frequency measurement are usually performed to determine the material property. In this paper, conductivity was investigated on used transformer oil which is affected by 30–150 seconds microwave heating as high-frequency wave. The results showed that the duration 30s until 90s of high-frequency wave exposure would be reduced the value of conductivity from 1,835×10⁻¹¹ mS/m to 1,60345×10⁻¹¹ mS/m and 1,69147×10⁻¹¹ mS/m to 1,4333×10 ⁻¹¹ mS/m respectively under negatif and under positif d-c voltage.