Recently, the 2025 plenary meeting of the Technical Committee on Power Capacitors and their Applications (IEC/TC33) of the International Electrotechnical Commission successfully concluded in Fribourg, Switzerland. This grand event, which gathered global industry wisdom, was held in a hybrid "offline + online" mode. It attracted 35 top experts from 13 P member countries, including Italy, Canada, Germany, Belgium, France, Sweden, India, and China. Together, they determined the new direction of international standards in the field of general capacitors, with multiple standard proposals and revision plans being implemented, injecting new impetus into the standardized development of the global general capacitor industry.
As the most authoritative international standardization organization in the field of power capacitors, IEC/TC33 focused on core application scenarios such as new energy grid connection, high-voltage direct current (HVDC) transmission, and low-voltage power control in this conference. It conducted in-depth discussions on the gaps and optimization needs of the standard system for general capacitors. Among them, two proposals from the Chinese delegation became the focus of the conference. With their technical foresight and practical value, they were recognized by many countries and officially launched the NP (New Work Item) project initiation process.
The "DC Filter Capacitors for High-Voltage DC Transmission Systems" proposal led by Professor Dai Chaobo from the China Electric Power Research Institute directly addressed the technical pain points in the context of large-scale new energy grid connection globally. For the first time at the international level, this proposal systematically defined the design specifications, test methods, and performance indicators of high-voltage DC filter capacitors and neutral bus capacitors, filling the gap in the IEC high-voltage capacitor standards in the HVDC transmission scenario. As the installed capacity of new energy sources such as wind power and photovoltaics continues to grow globally, the reliability requirements for filter capacitors in HVDC transmission systems are becoming increasingly stringent. After the implementation of this standard, it will provide a unified technical basis for global relevant equipment manufacturers, helping to achieve efficient and stable transmission of new energy power.
Another highly concerned proposal came from Professor Zhao Qicheng from the Zhejiang Electric Power Research Institute. His leading "Automatic Reactive Power Controllers for Low-Voltage Power Capacitor Devices" proposal sorted out the technical logic in the field of low-voltage reactive power compensation, clarified the performance requirements and test standards for automatic reactive power controllers, and filled the gap in the IEC standard system in this specific sub-field. More importantly, this proposal will serve as a core reference document for the revision of IEC 61921 "Power Capacitors - Low-Voltage Power Factor Correction Devices" Edition 3, further improving the international standard chain for low-voltage general capacitor devices. It will provide a unified standard for low-voltage reactive power compensation equipment in scenarios such as industrial plants and commercial buildings, promoting the energy efficiency improvement of the global low-voltage power system.
In addition to the initiation of new proposals, the conference also achieved key progress in the standard review session. The plenary session unanimously adopted the technical opinions submitted by the Chinese delegation, optimized the test process for S3-type capacitors in the IEC 60252 "Capacitors for AC Motor" series standards, clearly required that such capacitors need to conduct both DC and AC tests simultaneously, and refined the failure evaluation standards. Based on this opinion, the conference voted to launch the revision work of the IEC 60252 series standards, which will be led by Chinese expert Bao Junhua (convener of MT25). S3-type capacitors are widely used in fields such as industrial motors and household appliances. This standard revision will further improve product safety and reliability and reduce the failure risk of terminal equipment.
For the global general capacitor industry, the results of this IEC/TC33 conference are of milestone significance. Unified and improved international standards can not only reduce trade barriers caused by differences in technical specifications and lower the R & D and procurement costs of multinational enterprises but also guide industry resources to incline towards highly compliant and high-quality products, promoting the application upgrade of general capacitors in fields such as new energy, industrial automation, and consumer electronics. As the chairman of IEC/TC33 said, "The consensus reached in this conference is the result of multinational collaboration. It will draw a clear path for the technological innovation and market development of global general capacitors, helping the industry move towards a more standardized and efficient new stage."
Currently, various newly initiated standards have entered the draft preparation stage, and the revised IEC 60252 series standards are expected to complete the final review in 2026. Global industry practitioners and end customers can continuously follow the official news of IEC, keep up with the impact of standard updates on product design and procurement selection in a timely manner, and jointly seize the new opportunities for the standardized development of the general capacitor industry.
