DETERMINATION OF THE CAPACITANCE VALUE OF THE CONDUCTOR-INSULATOR-PIN SYSTEM IN 6-10 kV OVERHEAD POWER LINES TO ASSESS THE FEASIBILITY OF EARLY DIAGNOSTICS OF THE INSULATION CONDITION

The negative influence of single-phase-to-ground faults in networks with an isolated neutral, resulting from a break-down of pin insulation, is analyzed. A concept for early detection of damage to pin insulators is proposed, based on measuring changes in leakage current through the insulators caused by changes in the capacitance of the “pin-insulator-wire” system. For this purpose, a simulation of the system was done. A model of the geometric dimensions of the insulator is created with taking into account the design features of the installation of the line wire in the AutoCAD software package and the distribution of the electric field is simulated in the Comsol Multiphysics 5.6 package, which makes it possible to estimate the electrical capacitance. The dependence of the calculated electrical capacitance of ShF-20G insulators on the dielectric constant, diameters and grades of wires used on 6-10 kV overhead power lines and options for wire bundles is considered. Numerical values of the capacitance of the “pin-insulator-wire” system were obtained for different configuration options. It has been shown that the state of the insulator material has a deci-sive influence on the capacity of the system. References 11, figures 2, tables 2.