Shaanxi puts world's first 800-kV/80-kA breaker into operation

The world's first 800-kilovolt/80-kiloampere high-capacity circuit breaker was put into operation at the 750-kV Qindao switching station in Shaanxi province on June 5.

Led by the State Grid Shaanxi Electric Power Research Institute, the research team partnered with Xi'an Jiaotong University, the China Electric Power Research Institute and Henan Pinggao Electric to develop the equipment.

Boasting fully independent intellectual property rights, the breaker's all core components are domestically manufactured. It marks the world's first engineering application of a circuit breaker at this voltage and current rating, offering an effective solution to excessive short-circuit current in the Northwest China power grid.

It also provides important technical support for the safe operation of ultra-high-voltage grids and the development of a new-type power system.

In recent years, the 750-kV grid across Northwest China has undergone continuous upgrading. With large-scale integration of new energy resources and expanding UHV outbound power transmission, the grid has become more tightly interconnected. The issue of excessive short-circuit current has become acute, creating an urgent demand for domestically produced, high-capacity and highly reliable switchgear.

The research team built a high-precision arc simulation and performance evaluation system, optimized the design of the arc-extinguishing chamber, proposed a new approach to improve breaking performance, developed new materials for highly ablation-resistant contacts and nozzles, and created a highly reliable high-power operating mechanism. These efforts overcame core technical bottlenecks for interrupting extremely large fault currents.

The prototype was completed in February 2025. It passed all type tests on its first attempt in September of the same year and obtained product appraisal from the Chinese Society for Electrical Engineering in November. Its overall performance reaches an internationally advanced, filling a global gap in power equipment designed for UHV and ultra-large breaking current scenarios.

The commissioning of this domestically high-capacity circuit breaker represents a major breakthrough in China's independent research, development and engineering deployment of UHV high-capacity switchgear. It effectively improves the safety margin and stability of the Northwest China main power grid.

State Grid Shaanxi Electric Power will adopt differentiated, targeted operation and maintenance strategies. It will strengthen dynamic sensing and intelligent assessment of equipment health, and carry out targeted inspections under conditions such as heavy loading and frequent switching.

The company will also use advanced technologies like long-duration partial discharge monitoring and X-ray inspection to expand the scope of equipment condition evaluation. It will also keep improving operational performance and support high-quality grid development through original, pioneering scientific innovations.