On-Line Monitoring of Transmission Lines in Mining Cave-Ins Area

The ground deformation in mining area will cause the incline of tower and distortion of tower leg, which will influence the capacity of towers suffering from wind and icing load and threaten the safety of overhead transmission lines. This paper presents a new on-line monitoring system which can monitor the stress and sag of continuous span transmission lines, and the deformation condition of lattice tower located on mining cave-ins area. The incline angle of suspension tower and suspension insulator strings, atmosphere temperature, wind speed and wind angle are monitored, and the precise numerical method based on the catenary state function and the balance theory of suspension insulator is employed to calculate the stress and sag of overhead lines. The new on-line monitoring system is installed in a mining cave-ins area and works well.