Abstract: In view of the common heat generation problem at the joints of overhead transmission lines, by measuring the contact resistance, the heating risk of the line after power is transmitted is explored, and the selection of Kelvin double-arm bridge arm resistance parameters and other issues researched. Through control experiments with and without grounding loops, combined with simulation calculations, it is verified that the grounding loop will not affect the measurement results. In the accuracy experiment of preventing heating, the device's balanced score is 88.88%, and the recall rate is 100%, proving that the device has a high accuracy in preventing the heating problem of tension-resistant clamps. In addition, the advantage of the device is that there is no need to remove the wire clamp hardware at the joint during the detection process, thereby avoiding unnecessary damage to the equipment and ensuring the efficiency and safety of the detection process.

Key words: Kelvin bridge, contact resistance, heat generation at the joint, overhead line, micro-ohmmeter