Live working on electrode line of ± 800kV DC transmission project

It is necessary to research live working on UHV electrode line, so as to support DC UHV maintenance. As the electrode line of Zhengzhou converter station for example, the ground faults overvoltage on BP and GR modes were calculated. The maximum switching overvoltage was 288kV under the condition of live working. It was determined by the grounding fault of high end YY converter valves. The switching impulse flashover was carried in the live working air gaps of simulation tower. The results showed that the discharge voltages between worker's back and tower were lowest, and Discharge voltage of arcing horn was obviously higher than that between equipotent personnel and tower. The live working safety distance was calculated in usage. As the safety margin is 1.2, the safety distance is 0.65m. The electric field strength of live workers is less than 240kV/m, so the workers do not need to protect the electric field. And the maximum operating temperature of the conductor is less than 120 V, live working worker must avoid direct contact with high temperature wire, should use insulation tools or wear thermal insulation protective tools. Barehand method, insulating method and gloving method can be charged for electrode line. Above-mentioned results are available for reference to live working carried on other electrode lines of 800kV DC transmission project.