Absorption methods of control of technical condition of electrical insulation

The article provides an overview of the most common methods for monitoring the technical state of electrical insulation, based on the applying of absorption phenomena arising in dielectric materials under the influence of DC voltage. The main provisions of the control method based on determining the voltage at the electrodes of the investigated capacitive control object, which is recovering after a short-term discharge of its capacity, are described. The main aspects of the application of the polarization index and the absorption coefficient for determining the technical state of insulation by using the coefficients characterizing the change in time of the current through the dielectric when a constant test voltage is applied to it are analyzed. The advantages of using absorption methods for monitoring the technical state of electrical insulation, first of all, are the ability to carry out testing without the necessity of applying of relatively high test voltages, which greatly simplifies all the necessary technical operations. Such control methods show a significant dependence of the informative parameters used in them on the technical state of insulation on the degree of development of slow polarization processes in the material under study and, therefore, are successfully used to determine the degree of moisture in tested electrical insulation.