Space Charge Effect On The Electrophysical Characteristics Of Liquid Dielectrics

Liquid dielectrics are extensively used as an insulating and heat transfer agent in electrical apparatus. The electophysical properties of these insulating liquids are of vital importance to the service life of electrical equipment and have become increasingly important as operating voltages have increased to 500 kV and above and internal equipment spacing has decreased. We initially studied the current time characteristics of benzene, toluene and carbon tetrachloride under dc electric stress. The results demonstrated that the current decreased with the time, what could be explained by the creation of space charge near the electrodes. Current-voltage characteristics were constructed for different times of electrical field application. We have also conducted measurements of discharge currents, which led to obtaining the values of diffusion coefficient and space charges. From the reversal currents investigations it is possible to calculate the mobility of charge carriers. We added also the new data about reversal currents in hydrolique liquids. The model explaining the dependence of the resistivity on the distance between the electrodes is proposed.