On the measurement of the conductivity of highly insulating liquids

The present increasing interest for accurate conductivity measurements on highly insulating liquids is underlined. Criteria for valuable measurements are recalled. An apparatus using a new technology is briefly described. It allows us to perform a number of experiments and it is shown that accurate measurements of the conductivity of highly insulating oils can now be obtained at room temperature. Experiments carried out in an extended range of electrode gap distance from 0.7 to 7 mm, and of voltage from 0.1 to 100 V, demonstrate that we do measure the volume conductivity of the liquid. From a practical point of view, it is concluded that laboratory or in-line measurements on highly insulating oils can also be made using small volume of liquid or small electrode gap distance