The Longitudinal Impedance of Two-Chain Power Lines without a Lightning Cable in Phase Coordinates in the Problem of Remote Fault Location

Single-phase short circuit is the most common failure in a 110 kV network of any power supply system. At the same time, the detection and elimination of such a malfunction is a laborious process. This is especially difficult for overhead power lines with polymer insulators, where the damage cannot be seen without climbing to the top of the tower. Therefore, special software is needed for modeling the power system, calculating the parameters of steady-state and emergency modes, as well as remote detection of single-phase faults. The problem of remote localization of single-phase faults imposes certain requirements on the accuracy of the mathematical model of the overhead power transmission line. This is the introduction of the actual distance between the phase conductors. Now it is relevant for industrial power supply systems, where 110 kV power lines can be made with conductors designed for 220 kV. Such wires have reference data calculated for a geometric mean distance between phases of 15 m, which is almost twice as much as the phase-to-phase distance in a 110 kV system. The most convenient and accurate way to model overhead power lines is to use phase coordinates. But using this method is not always justified. The authors of the article have developed a combined equivalent circuit, in which the overhead line is modeled in phase coordinates, and the rest of the circuit elements are modeled in symmetric components.