Power Flow Modeling of Multi-Circuit Transmission Lines

To reduce the allocation of land for the construction of electric power facilities, it is possible to leverage multi-circuit overhead transmission lines (MCTLs), in which the conductors of several circuits of different voltage classes are placed on the same tower. The unique features of the arrangement of conductors on MCTL towers cause unequal inductances and capacitances of different phases. In addition, there are significant mutual electromagnetic influences on the line circuits. To account for these factors, it is advisable to model the power flow of electric power systems equipped with MCTLs using the phase frame of reference. On the basis of such models, it is possible to determine the power flows while taking into account lateral and transverse asymmetries and to analyze electromagnetic safety conditions along the routes of multi-circuit transmission lines. We proposed a technique for modeling power flows and electromagnetic fields of multi-circuit power transmission lines, in which conductors of several circuits of different voltage classes are placed on the same tower. The methodology is based on the application of phase coordinates, which are the most natural description of three-phase power systems. The method is versatile enough to be applied to solving the specified problems for MCTLs of different designs. The article presents the results of research aimed at developing a method for modeling MCTL power flows. The results of modeling power flows of an electrical network including a three-circuit power transmission line are presented. The practical use of the models developed by the authors will make it possible to make well-grounded choices regarding the options for the use of multi-circuit power lines.