Study on Direct Lightning Protection of $\pm\ 1100\text{kV}$ Converter Station Grid

The voltage level of HVDC transmission system in China has been raised from $\pm 500\ kV$ to $\pm 800\ kV$ and further to $\pm 1100\ kV$ The transmission power has been raised from 3000MW to 12000 MW. It is the highest voltage level and transmission power in the world. It puts forward higher requirements for system stability, insulation coordination, layout of converter stations and equipment performance. Converter station is key of the DC power system. Once a lightning damage accident occurs, it may cause a large area blackout, and the impact is very serious. The converter station requires reliable lightning protection measurements. DC valve hall and indoor DC field of $\pm\ 1100\ kV$ are higher than those of $\pm 800\ kV$ After height increase, the station lightning protection rod and line network could not effectively protect them. It was need to make lightning protection design alone for the valve hall and indoor DC field. In this paper, the design basis and design method of lightning protection for converter station buildings were given. By this method, the lightning protection design of valve hall and indoor DC field of $\pm\ 1100\ kV$ Changji and Guquan converter station were checked and optimized. The research results have important reference value and guiding significance for lightning protection design of buildings in DC converter station and AC substation. With the operation of $\pm 1100\ kV$ Changji-Guquan Project in 2019, the results of above research results will be gradually confirmed.