Influence of the shield grounding system on choice of section

Abstract

The choice of the ground circuit of a shield that gets rid of capacity losses is becoming especially urgent to increase the transmission capacity of lines with cross-linked polyethylene insulation. Ground systems of shields of the single-phase high-voltage power cables are studied. A mathematical model to select the section of the electric conductor for single-wire power cables for a voltage of 6–500 kV is suggested which takes into account the connection circuit of the shield permits allows one to determine the capacity losses and induced voltage on the shield. The method of selection of energy-efficient grounding systems of the shield of the three-phase group is found on the basis of the mathematical model. A selection criterion is suggested determining the relative rate of return of the “open” ground system with no currents in the shields over against the “closed” system in the shields of which parasitic currents flow.