Recently, the inaugural meeting of the Energy Industry Standard Working Group (TC333/WG5-2024) for the “Technical Specification for Medium-High Frequency Isolation Transformers Used in Flexible DC Systems” was successfully held in Xi’an. This standard is being drafted under the leadership of Tsinghua University, with Associate Professor Zhao Biao from the Department of Electrical Engineering and Applied Electronics (EEA) serving as convener. It is the first energy industry standard specifically for medium-high frequency isolation transformers.

The meeting was organized by the National Standardization Technical Committee for High Voltage Direct Current Transmission Equipment (SAC/TC333). It gathered representatives from 24 organizations, including Tsinghua University, Xi’an High Voltage Apparatus Research Institute, China Electric Power Research Institute, Southern Power Grid Research Institute, State Grid Economic and Technical Research Institute, Southern Power Grid UHV, China Three Gorges Corporation, State Grid Jibei Electric Power, Shougang Zhixin, Beijing Huairou Laboratory, Guangdong Power Grid, Xi’an Jiaotong University, NARI Relay Protection, Baoding Tianwei Baobian Electric, Shandong Taikai, Xinhualu Special Electric, Hebei Gaojing Electric, CRRC Qihong Heat Dissipation, Shandong Electric Power Equipment, Beijing Network DC Engineering, Fujian Intermediate Test Institute, Tangshan Feipin Technology, Guangdong Fude Electric, and Changzhou Borui Electric Power.

First Meeting of the Medium-High Frequency Transformer Standard Working Group

Medium-high frequency isolation transformers are the core components enabling energy conversion and electrical isolation in power electronic transformers. In recent years, this technology has matured significantly, and its engineering applications have grown exponentially in fields such as renewable energy integration and flexible distribution networks. However, there are currently no established standards for medium-high frequency isolation transformers, which has hindered coordinated high-quality development in product design, manufacturing, testing, and engineering applications. Achieving industry consensus on standards is urgently needed. The development of this standard is of great significance for promoting the industrial advancement of medium-high frequency isolation transformers and supporting the construction of new power electronic systems under high renewable energy penetration.

At the meeting, Xu Fan, Secretary-General of the Standard Committee, highlighted the importance of the standard and clarified the meeting objectives. Professor Cui Bin from the National Key Laboratory for Operation and Control of New-Type Power Systems at Tsinghua University presented the main contents of the draft standard. Experts present engaged in extensive and thorough discussions on the standard’s structure, terminology, technical requirements, and testing protocols, laying a solid foundation for subsequent standardization work.

In recent years, the DC Research Center team of EEA has conducted systematic research on the fundamental theories, key technologies, and core equipment of medium-high frequency isolation transformers. Collaborating with several domestic manufacturers, the team has developed a series of medium-high frequency isolation transformers successfully applied in key projects such as the Ulanqab source-grid-load-storage system, Dongguan Songshan Lake flexible medium-voltage interconnection, and Qinghai Haixi Ge’ermu DC integration project. These efforts have actively promoted the standardization and product development of medium-high frequency isolation transformers.