Continuous measurements of electric field vector maps in nitrobenzene and propylene carbonate

For electrical insulation diagnosis, it is necessary to obtain information about the electric field distribution and the space charge distribution in insulation materials. We have investigated the measurement of nonuniform electric field vector distributions in liquid dielectrics using an original method based electrooptic Kerr effect and CT method. By the way, nitrobenzene has often been used in Kerr effect measurements because its Kerr constant is very larger than other liquids. However, nitrobenzene belongs to deleterious substances and it is very difficult to treat it. In contract, propylene carbonate is much safer and its Kerr constant is comparable to nitrobenzene. In addition, it is very interesting to measure the change of the electric field distribution because propylene carbonate has a strong dipole. In this paper, we report on the measurement of the electric field vector distribution changing with time in ms order when a voltage pulse or DC voltage was applied to a electrode system in propylene carbonate nitrobenzene, and both was compared.