Recently, the work group for establishing the energy industry standard “Technical Code for DC Transformers in DC Distribution Systems” (Task No.: Energy 20220193) was founded and the first work meeting was successfully held in Xi’an. This standard will be drafted under the leadership of Tsinghua University with Associate Professor Zhao Biao of the Department of Electrical Engineering and Applied Electronics (EEA) as the convener, and will be the first energy industry standard in the field of DC transformers.

The meeting was organized by the Committee of Power Electronics for Power Transmission and Distribution Systems of the National Power Electronics Systems and Equipment Standard Committee (SAC/TC60/SC2), and was attended by 38 representatives from 26 organizations including Tsinghua University, Xi’an High Voltage Research Institute, State Grid Economic and Technical Research Institute, China Southern Power Grid Ultrahigh Voltage Transmission Company, State Grid Smart Grid Research Institute, Three Gorges Group Science and Technology Research Institute, Guangdong Power Grid, Jiangsu Power Grid, Shandong Power Grid, Guizhou Power Grid, Beijing Power Equipment Group Co., Ltd., Xi’an XD Power Systems Co. Ltd., XJ Electric Co., Ltd., Shandong Taikai, Xi’an Power Electronics Technology Research Institute Co. Ltd., Tianjin University, North China Electric Power University, Central South University, Southeast University, and Beijing Information Science & Technology University.

1st Meeting of the Standard Work Group

DC systems are an important technology direction to support high proportion of new energy access and flexible and efficient energy use. DC transformers are the core basic equipment to realize interconnection of high/medium/low voltage DC system and build AC/DC converged grid. In recent years, the technology of DC transformers is becoming more and more mature, engineering applications are accelerating, but there is still no standard for DC transformers, which is not conducive to the design, manufacture, testing and engineering applications of synergistic high-quality development, and thus there is an urgent need to reach a consensus in the industry. The establishment of this standard will be of great significance in promoting the industrial development of DC transformers and the construction of a new AC-DC converged grid in the context of high proportion new energy.

At this meeting, Professorate senior engineer Zhou Huigao, director of the standard committee, explained the importance of the standard and clarified the objectives of this meeting, the team of DC Research Center of Energy Internet Research Institute of Tsinghua University introduced the main contents of the draft standard, and the experts present had extensive and serious discussions on the standard structure, definition of terms, technical requirements, tests and other contents, which laid a good foundation for the follow-up work.

Serialized DC transformer products

In recent years, the team of DC Research Center of Energy Internet Research Institute of Tsinghua University has carried out systematic research on basic theories and devices, key technologies and core equipment of DC transformers, developed the world largest capacity DC transformer, and cooperated with several domestic manufacturers to realize the development of multi-scenario serialized DC transformer equipment, which has been successfully applied in many flexible power transmission and distribution projects including Ulanqab “Source-grid-load-storage” Smart Energy Demonstration Project and Dongguan Songshan Lake Flexible Medium Voltage Interconnection Project. This will play an important role in promoting the further development and application of DC transformer-related standardization work and products.