Abstract:The reliability of ultra-high-voltage (UHV) alternating current (AC) switch-gear and bushing during its whole life cycle has always been a major concern of Power Grid Corporation and manufacturers. The study of long term live test is the key to ensure safe and stable operation of bulk power grid. In this paper, the layout of test field, the technical parameters of main test equipment, impedance calculation of the 1 100 kV/10 kA test loop and the design of auxiliary grounding grid are described in detail. As the gas-insulated switch-gear (GIS) enclosure of 1 100 kV/10 kA power current transformer (power CT) has no external circulating channel, a special copper bar grounding grid is designed to form a complete loop. Its active power consumption, terminal voltage are calculated and verified. Meanwhile, considering that the project is located in the middle thunderstorm region, this paper designs a lightning protection system, which improved the lightning protection level of the test equipment and test object.