Study on Xiluodu and Xiangjiaba UHVDC Earth Electrodes

Grounding characteristics of linear, star-type and toroidal electrodes are discussed in this paper. Based on the analysis of the performance of double-ring in uniform and horizontal two-layer soils, an electrode model of standard triple concentric rings buried with different depth is presented for plusmn800 kV Xiluodu and Xiangjiaba converter stations in the first period of Jinsha River DC projects. Considering the three sending converter stations in the projects close to each other relatively, an initial analysis of sharing electrodes has been made, including the operation mode of converter stations, choice of rated current and the design model of electrodes. Simulation results obtained from the electrode sites primarily selected for Xiluodu right-bank converter station show that the above model can satisfy the operation requirements with a better economical performance and sharing electrodes by multi-converter stations is also feasible. They may supply some reference to the practical projects.