Objective Conductors and ground wires are important component of transmission lines, which play the roles of transmitting electrical energy and lightning protection respectively. The coordination between conductors and ground wires is of great significance for the safe operation of transmission lines.

Method By establishing a state equation for the conductor and ground wire of transmission lines, the control meteorological conditions for different representative spans were obtained through calculations based on the parameters of the conductor and ground wire. The sag variation laws of transmission lines with different spans under four different combinations of conductors and ground wires and under different meteorological conditions were analyzed. The distances between the conductor and ground wire under different spans in calm atmospheric conditions were calculated and verified, and suggestions and solutions for increasing the distance between the conductor and ground wire were proposed.

Result The calculation results indicate that for the meteorological conditions in coastal areas, as the span increases, the coordination of the distance between conductors and ground wires does not meet the requirements of the regulations, and the larger the speed of wind, the larger the range of spans that do not meet the requirements. For the meteorological conditions in mountainous areas without icing, four different combination of conductors and ground wires meet the requirements of the regulations; For the meteorological conditions in mountainous areas with 10mm icing, with the conductors and the grounding wires JL/LB20A-720/50&OPGW-150, when the span is not less than 700 m, the distance between the conductors and the ground wires does not meet the requirements of the regulations. Without meeting the requirements of the regulations, the distance between the conductors and the ground wires can be increased by tightening the ground wires.

Conclusion For newly built or renovated transmission lines in coastal areas and mountainous areas with 10mm icing, special attention should be paid to the verification of the distance between the conductors and the ground wires. When the distance between the conductors and the ground wires does not meet the requirements of the regulations, it can be increased by tightening the ground wires to meet the requirements of the regulations.