Jibei Electric Power's major original achievement "Flexible Substation Technology" is at the international leading level

On September 19, the "Key Technologies, Complete Equipment and Engineering Applications of Flexible Substations" passed the technical appraisal of the Chinese Society of Electrical Engineering. Experts from the appraisal committee unanimously agreed that the project achieved original innovation in the topological structure of high-voltage power electronic converters, conquered the key technologies of core equipment of flexible substations and realized engineering applications, possessed independent intellectual property rights, and had an internationally leading overall technology.

Since 2016, during the construction of the Zhangbei flexible substation and AC/DC distribution network demonstration project, State Grid Jibei Electric Power Co., Ltd., in collaboration with the Global Energy Internet Research Institute Co., Ltd., organized Jibei Economic Research Institute, Electric Power Research Institute, Zhangjiakou Power Supply Company and other units, and reached cooperation agreements with customers such as Alibaba Group and Elion Group. Through multiple rounds of demand surveys, they proposed the original concept and technical solution of "flexible substation" based on power electronics technology, which not only met the new needs of data centers for high-reliability power supply, green energy use and DC power supply, but also realized the efficient on-site consumption of photovoltaic poverty alleviation power generation; carried out key technology research, overcame technical difficulties such as converter topology innovation, material design process, AC/DC hybrid distribution network protection and control, and dynamic seamless load distribution, and achieved major technological breakthroughs; overcame difficulties such as no precedent, no standard reference, and construction in extremely cold winter conditions, carried out a complete set of AC/DC distribution network design based on flexible substations, formulated a series of technical standards, and completed the demonstration project construction with high quality.

This technical project is outstanding in its innovation and demonstration. It proposed a main circuit topology for the self-balancing of three-phase fluctuating power in a multi-port flexible substation, which reduced the DC support capacitance by 85% and increased the power density by 200%. It innovated the technology and process of all-solid-state high-frequency transformers, effectively improved the power density of the transformer and ensured the integrity of the insulation. It proposed AC/DC fault protection and system rapid recovery technology to achieve coordination and compatibility with conventional protection, avoid protection over-response, and achieve high-reliability power supply for loads. It proposed engineering application technologies such as complete set design of AC/DC distribution network based on flexible substations, digital and analog detection test methods of control and protection systems, developed a series of core equipment for flexible substations with completely independent intellectual property rights, built the world's first demonstration project of AC/DC distribution network based on flexible substations, and explored new forms of future distribution network development.

The project results have been applied to demonstration projects such as the Zhangjiakou Winter Olympics Zone and Handan, Hebei, and have been listed as preferred technologies by the Power Big Data Centers of State Grid Gansu Electric Power Company and State Grid Tianjin Electric Power Company. It will play an important role in the networking of AC and DC distribution networks, reliable and efficient power supply for data centers, and distributed photovoltaic access, and has broad application prospects.