Design of 1100kV/I0kA Ultra-High-Voltage Alternating Current Long-term Live Test Loop

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 technical parameters of main test equipment, impedance calculation of the 1100kV/I0kA test loop and the design of auxiliary grounding grid are described in detail. As the Gas-insulated Switch-gear (GIS) enclosure of 1100kV/I0kA 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, shunt capacitor are installed at both ends of the Power CT to compensate the inductive reactive power of the test loop and reduce the section of the winding and power capacity requirement. The future work on the AC long term live test loop is also briefly discussed.