Single-Circuit Power Transmission Lines of High Voltage 110 and 220 kV with Increased Throughput, Reliability, and Efficiency

Traditional single-circuit high-voltage AC lines, widely used throughout the world, are characterized by a significant disadvantage, which is that when the most probable single-phase permanent failures occur, the line is completely disconnected. This article discusses single-circuit high-voltage lines, one phase of which is built in the form of two parallel operating semi-phases, either of which is used as a backup phase in failure modes, and series capacitors are included at the ends of the line in two normal phases for mode symmetry. An algorithm has been developed for calculating normal modes. Using the example of the proposed 110 and 220 kV innovative lines, the relation between their capacity and the capacity of two-circuit traditional lines is shown. A scheme is proposed that makes it possible, in case of permanent damage to one of the semi-phases or one of the phases, to switch to operation in post-failure mode with the possibility of transmitting at least 50% of the power of the initial maximum mode. A technical and economic comparison of two-circuit traditional and single-circuit 110 and 220 kV innovative lines was carried out.