Optical measurement of electric field in a dielectric liquid containing space charges

We have investigated the measurement of nonuniform electric field vector distributions in liquid dielectrics using an original method based on electrooptic Kerr effect and CT method. Recently, we developed an optical system that could measure electric field distributions of the order of a mili-second. The temporal change of the electric field distribution obtained by this system would allow us to study a behavior of a space charge and an electrical conduction in liquid insulations. In this study, we carried out the electric field in a liquid containing space charge. The space charge could not be evaluated quantitatively, so liquids left for scores of minutes from the first sequence of the applied voltage were used. By changing the time required for leaving, the quantity of charge in liquids was changed. It was well known that the electric field strength in liquids containing charges was not a static field. The change of the electric field caused by charges in liquids was very interesting.