A study of the electric-field intensity of conductors of a 500-kV air line

Abstract

Electrostatic-field intensities have been obtained by mathematical simulations of the electric field of AS conductors of a 500-kV air line (AL) and numerical analysis based on the finite-element method using the Ansoft Maxwell software. The irregularity of the wire surface of an air line and the inhomogeneities of surface of the last cable layer have been taken into account in the study. The latter lead to a local increase in the field intensity, which, in turn, results in a loss of useful power. Phase splitting is used to decrease the electric- field intensity on air lines. Furthermore, the intensity on the individual wire decreases and, as a result, loss of power is reduced with respect to the corona discharge and line inductive reactance. Thus, to decrease loss of power of wires and to prolong the lifetime of wires, it is necessary to determine correctly the cross section of wires and kind of phase splitting. A 2D mathematical model of the AL electrostatic field has been developed that takes into account the inhomogeneity of the shape of the wire surface. The analytical solution of the initial problem has been considered, and the numerical and analytical results for a cylindrical wire surface have been compared. The fields for four cases of an AS conductor with different versions of splitting have been studied. The curves of field intensities near a conductor surface as a function of the cross section and number of wires in the AL phase have been plotted.