Ma Qingyang1, Zheng Quanxu2*, Sheng Junyi2, Xie Wenjie2, Liu Ping2, Yang Bin2,

Driven by China"s "30·60" Dual Carbon Goal, the construction of large-scale new energy bases in deserts, Gobi and desertified areas has become the core path for China"s green energy transition. Most of these bases are located at the end of the power grid, and the traditional AC collection and transmission scheme has such problems as redundant conversion links, insufficient grid support capacity and prominent wide-band oscillation risk, which significantly restricts the grid connection and consumption of large-scale new energy.The full-DC collection and transmission technology based on Modular Commutated Converter (MCC) proposed by Tsinghua University, through topological innovation, can improve transmission efficiency, enhance grid connection stability and reduce engineering construction costs. It has now become an important technical solution for new energy grid connection in photovoltaic bases in deserts, Gobi and desertified areas, and provides core support for the development of ten-million-kilowatt-level new energy bases.This paper focuses on the research of insulation design technology of MCC single-phase converter valve. Firstly, the insulation parameters between key potential nodes of MCC single-phase converter valve are determined, and the three-dimensional layout design of the converter valve structure is completed. Secondly, electric field simulation of the valve tower is carried out to analyze and calculate the overall electric field intensity distribution law of the valve tower. Finally, a 1:1 proportional single-phase valve tower test platform is built, and insulation performance tests under multiple working conditions are completed to verify the reliability of the insulation design of the converter valve.