China Achieves Major Breakthrough in Ultra-High Voltage Circuit Breaker Technology with World's First 800 kV / 80 kA Circuit Breaker

On November 9, the 800 kV / 80 kA large-capacity circuit breaker, jointly developed by State Grid Shaanxi Electric Power Company Limited, Henan Pinggao Electric Co., Ltd., and other partners, successfully passed technical appraisal and was recognized as reaching a world-leading level.

800 kV / 80 kA Circuit Breaker Sample

800 kV / 80 kA Circuit Breaker Capacity Test

During the development of the 800 kV / 80 kA circuit breaker, the project faced challenges including a 60% increase in short-circuit current energy, a 27% rise in the rate of recovery voltage increase, and significantly enhanced ablation resistance requirements for key components. The team innovatively established a high-precision simulation model for the full interruption process, built an internationally advanced arc measurement system to accurately characterize high-voltage, high-current arc properties, and successfully developed the world's first 800 kV / 80 kA dual-break arc-extinguishing chamber. In addition, they pioneered ablation-resistant graphene contact materials to meet the requirement of 20 electrical endurance operations and optimized the actuating mechanism and buffer structures, overcoming critical challenges in high-capacity switching coordination.

Arc-Extinguishing Chamber of the 800 kV / 80 kA Circuit Breaker

"The new circuit breaker achieves world-leading performance specifications while maintaining the same dimensions as current equipment, enabling direct replacement and upgrades and significantly enhancing the efficiency and economic viability of grid expansion projects," said Sheng Yong, Chief Expert of State Grid Shaanxi Electric Power Company Limited. Upon commissioning, the device will substantially strengthen the Northwest Power Grid's capacity to handle extreme short-circuit currents, ensure the security and stability of outbound power transmission networks for energy clusters, and provide robust equipment support for China's main power grid.