Due to the magnetic coupling between the phase line and the ground wire, the induced electromotive force is formed in the ground wire, producing inductive current and power loss in the current circuit between the ground wire and the earth, reducing the efficiency of power deliver. With the increase of power deliver and the improvement of the voltage level of the power network in China, especially the emergence of UHV AC transmission line, the power loss of ground wires caused by the magnetic coupling cannot be overlooked. At present, many studies focused on how to reduce the power loss of ground wires and various engineering measures have been adopted to reduce the power loss of ground wires, such as single point grounding, graded insulation and transposition technology, etc. However, most researches are based on the case that conductors and ground wires are installed in the same tower, while there is no relevant research on the parallel transmission lines where conductors and ground wires are installed in the different tower, especially those researches about the influence of phase sequence arrangement on the power loss in parallel transmission lines. Taking the 750kV parallel transmission lines now widely constructed in northwest China as example, this paper studies the characteristics of ground wire power loss under different phase sequence arrangement and different parallel distance, so as to illustrate the best energy saving phase sequence arrangement.

Parallel transmission line; Ground wire; Power loss; Inductive currents; Phase sequence arrangement.