Zero-sequence impedance of overhead transmission lines with discontinuous ground wire

The authors give a method to calculate the zero-sequence impedance of a transmission line having ground wires that are not continuous or are not connected to the station grounds at the end of the line. The calculated values are compared with the measured zero-sequence impedance of a line. The authors observe that for transmission lines having discontinuous ground wires, the actual zero-sequence impedance is different from the zero-sequence impedance of the line calculated with the classical methods and considering either no ground wire or continuous ground wire. This difference is significant if the ground wire is of ACSR conductor. The method given for calculating the zero-sequence impedance of a transmission line with discontinuous ground wire gives more accurate results, which are close to the measured values