World’s First 500kV/90kA Cost-Effective AC Current Limiter: R&D Success & Grid Trial

Recently, the world’s first 500kV/90kA cost-effective high-voltage AC current limiter, jointly led by Guangzhou Power Supply Bureau of Guangdong Power Grid and developed by China High-Voltage AC Current Limiter Manufacturer, successfully completed artificial short-circuit tests and has been officially connected to the grid for trial operation on the Shunguang Jia Line at the 500kV Guangnan Substation. As a key project under China’s National Key R&D Program, the successful completion of the “Development of 500kV and Above Cost-Effective High-Voltage AC Current Limiters” has filled a domestic technological gap in economical suppression of ultra-high short-circuit currents in AC systems. It provides an economically viable and reliable solution for limiting high-voltage AC short-circuit currents and offers strong support for the secure operation of extra-high-voltage large-scale power grids.

China High-Voltage AC Current Limiter Manufacturer attached great importance to this project, classifying it as a Category-A key R&D initiative within the Group. The company scientifically organized and coordinated resources, with its dedicated business division taking the lead. Internally, it integrated multi-party resources, conducted joint R&D, and carried out collaborative technical breakthroughs. After three years of effort, the team successfully completed all development tasks of the project.

Innovation-driven Breakthroughs – Achieving “Multi-Point” Advances
In product structural design, a tank-type fast switch scheme was adopted, resolving challenges such as powering secondary components of the fast switch on a high-voltage insulation platform and difficulties in maintenance due to the entire assembly being placed in a high-voltage environment. The project overcame multiple technical hurdles, including the development of high-strength insulating pull rods, high-power repulsion-driven mechanisms, bellows for high-voltage-differential and high-speed vacuum interrupters, research on the interruption characteristics of vacuum interrupters under high-speed conditions, arc-quenching characteristics of high-capacity vacuum interrupters with high DC components, and mechanical structural strength design of components under electromagnetic repulsion forces. On the secondary control side, the team solved key issues such as the development of high-voltage thyristor drive modules, design of the current-limiting controller system, rapid fault detection and identification, and ensuring reliable operation of secondary control systems in intense electromagnetic environments.

Collaborative Advancement – Promoting Integration of “Primary and Secondary” Systems
The product technology involves interdisciplinary integration across reactor, switchgear, vacuum interruption, power electronics, and microelectronics. It encompasses system analysis and calculation, system integration, primary electrical equipment technology, intelligent technologies for fault detection/identification and control/protection—representing a strategic direction for the Group’s new technology development. This integration of primary and secondary systems also supports the expansion of related diversified businesses. Throughout the project, enterprises within the Group fully leveraged their collaborative advantages, with seamless cooperation across companies, departments, and personnel to ensure timely and successful project completion.

Efficient Organization – Implementing “Project-Based” Management
The project adopted the IPD (Integrated Product Development) R&D model. Coordinated by China’s Ministry of Industry and Information Technology (MIIT), Guangdong Power Grid Company, China High-Voltage AC Current Limiter Manufacturer, and its affiliated enterprises, the management structure featured layered oversight, a dedicated project supervision team, and specialized task forces with clear objectives and assigned responsibilities. The effectiveness and planning discipline of project management were especially evident during manufacturing. Thanks to comprehensive efforts in early-stage innovative R&D, collaborative development, and system-level R&D, the engineering design, reliability validation of manufacturing processes, production and inspection of first-batch components, installation/maintenance procedures, and full-system commissioning of the pilot demonstration unit were all completed in less than four months—demonstrating remarkable “Chinese speed.”

The successful completion of this project is a concrete action by China High-Voltage AC Current Limiter Manufacturer to implement the national directive to “accelerate the establishment of original technology sources and become a modern industrial chain leader.” It also represents another practical step in executing the Group’s “core business focus with related diversification” development strategy. This achievement not only reflects the Group’s ongoing commitment to leading industry advancement but also showcases the Chinese spirit of perseverance, responsibility, pragmatism, and bold innovation in the face of challenges.