Overhead ground-wire cable taken into account while modeling the transmission of lower quality electrical power
Equivalent circuit and mathematical model have been proposed for transmitting the lower quality electrical power by means of three-wire overhead power transmission lines with overhead ground-wire cable. Equivalent circuit given in article takes the overhead ground-wire cable into account and describes its connection with current-carrying parts of power transmission lines and the ground. Longitudinal parameters of the power transmission line have been presented on the equivalent circuit by means of running active resistances of linear wires and overhead ground-wire cable and by means of their own running inductance. Transverse parameters of the analyzed site of the power transmission line illustrate electromagnetic couplings between linear wires as well as between linear wires and the ground. Mathematical model of a section of the power transmission line has been constructed on the basis of the equivalent circuit and by using Kirchhoff''s laws. The model consists of fourteen equations and helps to analyze the distribution of voltage and current along the investigated area of a high voltage power transmission line. It has been shown that when analyzing the transmission of lower quality electrical power, the power transmission lines, even of comparatively small extension, should be regarded as power transmission lines with distributed parameters. The equivalent circuit for such lines should be full-phased. When modelling mathematically the transmission of electric power, all electromagnetic couplings between current-carrying parts of transmission lines should be taken into account.