Recently, the flexible DC project of China Three Gorges Corporation located at the Mile Wind Farm in Yunnan Province has been successfully put into operation. The project is invested and constructed by China Three Gorges Corporation, jointly implemented with Tsinghua University, China Southern Power Grid Research Institute Co., Ltd., Xi'an XD Power Systems Co., Ltd., XJ Electric Corporation and NR Engineering Co., Ltd., etc. S-EIRI DC Research Institute has participated in its research and development. It's a key sci-tech research project under the sci-tech award system of National Development and Reform Commission. The project is the world's first new energy flexible DC project with IGCT devices, and also the world's first flexible DC project with 6.5kV power semiconductor devices. It's another significant breakthrough in IGCT flexible DC technology after projects such as Zhuhai DC Distribution Project, Dongguan Medium-voltage Interconnection Project, and Ulanqab Source-Grid-Load-Storage Project. It will impulsively promote the large-scale engineering application of IGCT flexible DC technology in scenarios such as desert, Gobi, barren land, offshore wind farm and urban power grids.
【 Introduction to IGCT Flexible DC Technology Route 】
Flexible DC technology is the strategic core to support China's carbon peaking & carbon neutrality goals. IGBT flexible DC technology route was first proposed by Europe and the United States, and then widely applied globally. Recently, the voltage and capacity of flexible DC projects have increased rapidly. Especially with the speedy implementation of China's carbon peaking & carbon neutrality goals, the voltage and capacity applied in flexible DC projects of China have increased by hundreds of times.
China is the first to propose the IGCT flexible DC technology route in the world. With low-frequency and large-capacity, IGCT devices are naturally suitable for application scenarios of flexible DC transmission. Recently, the technical bottleneck of IGCT flexible DC converter valve has been gradually tackled. Compared with existing flexible DC projects, the application of larger-capacity 6.5kV and 8kV IGCT devices will reduce the cost, volume and loss of the converter valve by over 30%. Moreover, as whole-wafer devices, IGCT devices have surge current tolerance and intrinsic explosion-proof characteristics, which makes flexible DC converter valve have stronger transient fault tolerance and active support capabilities.
Now, manufacturers such as Xi'an XD Power Systems Co., Ltd., XJ Electric Corporation, NR Engineering Co., Ltd., TBEA Co., Ltd., and Rongxin Huike Electric Co., Ltd. have produced IGCT converter valve products, laying an industrial foundation for the large-scale application of IGCT flexible HVDC transmission. With the mature application of 4-inch IGCT devices in flexible DC projects, larger-capacity IGCT devices of 4.5kV/12.5kA (current-carrying capacity of 6.25kA) and 6.5kV/10kA (current-carrying capacity of 5kA) based on 6-inch chips will be successively produced. The advantages of IGCT flexible DC technology route such as low cost, low loss, high reliability and intrinsic safety will be further highlighted.
IGCT Whole-wafer Chips and Devices
【 Project Introduction 】
The Mile Project in Yunnan is located in Shiwan Village, Hongxi Town, Mile City, with an altitude of up to 2,500 meters. The IGCT converter valve components are fully consistent with offshore wind farm flexible HVDC transmission projects, with the application of 288 fully domestic IGCT-Plus devices of 6.5kV/4kA (current-carrying capacity of 2kA). It represents a comprehensive engineering inspection of the IGCT device and its converter valve technology. During the commissioning phase, the inspection was carried out in strict accordance with the standards of offshore wind power projects. The project has successfully passed over 100 inspection items on steady-state, transient-state and protection functions, demonstrating reliability level beyond current technologies. On December 24, 2024, after an uninterrupted 168-hour trial operation, the project entered formal operation.
The project will provide valuable operational experience for future application of IGCT flexible DC converter valve in areas such as desert, Gobi, barren land, offshore wind farm and urban power grids, and enhance China's leadership in the new-generation flexible DC technology route.
IGCT Flexible DC Project Converter Station of China Three Gorges Corporation in Mile, Yunnan
IGCT Converter Valve Room
IGCT Flexible DC Rectifier Valve and Inverter Valve
