As a power infrastructure directly facing power users, transmission line is the direct power source of end users. Therefore, the normal operation of transmission line is a key link to ensure high-quality power supply service. Due to the wide range of transmission line erection, the erection site is mainly in urban areas with complex environment, and the insulation level is lower than the transmission network, resulting in high failure rate, heavy maintenance workload and more power outages caused by maintenance. In order to ensure the reliability demand of users, improve the satisfaction of users, and reduce the power failure caused by maintenance and fault, live working technology is proposed and applied to practical production. Live working is a kind of operation mode for inspection and maintenance under the condition of keeping all equipment of power grid without power failure. At present, most of the maintenance work and accident handling work in the transmission line can be completed under the condition of live operation. Therefore, the implementation of live operation can significantly reduce the power outage duration and power outage times of users and improve the reliability of power supply.