Recently, the State Grid Henan Electric Power Company Electric Power Research Institute of China (hereinafter referred to as "State Grid Henan Electric Power Research Institute") officially completed the formulation of the "Technical Supervision Implementation Rules for Key Points in the Whole Process of Hybrid Commutated Converter." This marks the first time a significant technical gap in this field has been filled, laying a solid foundation for technical supervision of the engineering transformation and application of Hybrid Commutated Converter.

For a long time, the "heart" of the direct current transmission projects—thyristor-based converter valves—has faced persistent challenges of "commutation failure" caused by the disturbances in the AC system. This issue has restricted the capacity for large-scale transmission of clean energy from the western regions to the load centers in the central and eastern parts of the country. In response, the State Grid Henan Electric Power Research Institute has actively implemented the requirements for technological innovation, aiming to resolve the significant issues and technical challenges related to the development and safe operation of the Henan power grid. As a result, it has innovatively adopted a Hybrid Commutated Converter technology route based on fully controlled Integrated Gate-Commutated Thyristor (IGCT) devices to tackle the "commutation failure" problem.

Since 2021, the State Grid Henan Electric Power Research Institute has collaborated with Tsinghua University and other institutions to conduct research on Hybrid Commutated Converter technology. This initiative led to the introduction of a new technology based on IGCT devices, achieving the world's first reduction of the minimum extinction angle of the converter valves to 2°, fundamentally eliminating the risk of commutation failure in conventional DC system. Through topological innovations, the team has also overcome the challenge of voltage balancing in series-connected devices at the hundred-level by achieving breakthroughs in voltage precision clamping. In addition, they proposed a three-tiered collaborative method for transient stress protection in Hybrid Commutated Converter, encompassing "device-equipment-system," which ensures the intrinsic safety of electromagnetic transients of the equipment. By focusing on the reliability verification of key parameters and functions, they developed new experimental techniques for the novel converter valve, filling the technical gap in the testing field.

Ultimately, after undergoing multiple rounds of rigorous testing and iterative improvements, the team successfully developed the world's first Hybrid Commutated Converter equipment which has passed the type tests. In July 2023, the Hybrid Commutated Converter was rated as "internationally leading" by the China Machinery Industry Federation, and in September 2024, it was selected in "Guidance Catalogue for the Promotion and Application of the First Major Technical Equipment (2024 Edition)" published by the Ministry of Industry and Information Technology of China. It is reported that the world's first Hybrid Commutated Converter is scheduled for technical transformation and application at the State Grid Henan Electric Power Company DC Center Lingbao Converter Station from September to November this year.