The world's first 800 kV / 80 kA circuit breaker has passed national-level technical appraisal.

On November 9, a new type of circuit breaker for gas-insulated metal-enclosed switchgear—designated ZF27-800(L)/Y6300-80—successfully passed a national-level technical appraisal organized by the Chinese Society for Electrical Engineering (CSEE) in Beijing. Developed jointly by a leading Chinese manufacturer of gas-insulated metal-enclosed switchgear and multiple partner institutions, this world-first 800 kV, 80 kA circuit breaker, featuring full independent intellectual property rights, has achieved internationally leading comprehensive performance metrics. The appraisal committee unanimously endorsed its breakthrough capabilities, marking another major milestone for China in the field of ultra-high-voltage (UHV) switching equipment and signaling the country’s successful entry into previously uncharted technological territory.

This innovative product was spearheaded by State Grid Shaanxi Electric Power Company, in close collaboration with the Chinese switchgear manufacturer, Xi’an Jiaotong University, and the China Electric Power Research Institute—a model example of deep integration among industry, academia, research, and end-use applications. The R&D team established a high-precision modeling method for nozzle arc dynamics in high-voltage circuit breakers and developed an advanced interruption performance evaluation model, thereby overcoming the globally recognized technical challenge of 800 kV / 80 kA current interruption.

This achievement not only provides a safe, efficient, and reliable solution to the growing problem of excessive short-circuit currents in China’s 750 kV power grid but also significantly enhances the security, stability, and transmission capacity of large-scale power systems. It further facilitates the integration of massive renewable energy sources and strengthens the reliability of national power supply. Moreover, it lays a solid foundation for advancing China’s power equipment technology toward even higher voltage levels and greater interrupting capacities—representing a critical step in transitioning China’s domestic power equipment industry from “follower” to “peer competitor” and ultimately to “global leader,” underscoring China’s dominant position in UHV switching technology worldwide.

Currently, as China advances through a pivotal stage of building a modern socialist country, the high-quality development of its economy and society demands more secure and stable energy supplies. With the continuous expansion of the power grid, large-scale integration of renewable energy, and accelerated construction of a new-type power system, short-circuit currents at certain substations have already exceeded 63 kA. This escalating risk of short-circuit overloads and system instability urgently calls for domestically developed, high-end switching equipment with 80 kA interruption capability as a robust technical backbone.

In response, State Grid Shaanxi Electric Power and the Chinese switchgear manufacturer leveraged their respective leadership strengths, pooled resources, and formed a cross-disciplinary joint task force to complete key technological research and prototype development for 80 kA high-capacity switchgear—delivering core technologies and equipment essential for the new power system.

According to reports, the newly appraised ZF27-800(L)/Y6300-80 circuit breaker features three major advantages:

• World-leading technical specifications and exceptional reliability:
  The product achieves the highest standard ratings—E2-M2-C2—with an electrical life of 20 operations, mechanical life of 10,000 operations, and a DC time constant of up to 120 ms.

• Mature, reliable structure with stable insulation and mechanical performance:
  Built upon the proven technical platform of existing 800 kV / 63 kA circuit breakers, it retains a dual-break puffer-type arc-quenching chamber and hydraulic operating mechanism. Enhanced contamination control and optimized transmission systems further improve insulation integrity and mechanical reliability.

• Full dimensional compatibility for seamless engineering deployment:
  The new breaker shares identical external dimensions and interface specifications with currently deployed 800 kV / 63 kA units, enabling direct in-situ capacity upgrades at substations without modifying civil structures or foundations—offering significant advantages including shorter outage durations, minimal operational disruption, and outstanding cost-effectiveness.

A senior executive from the Chinese gas-insulated switchgear manufacturer stated that the company will firmly implement China’s innovation-driven development strategy, embedding technological innovation throughout its growth trajectory. Aligned with its strategic vision of “building a world-class smart electrical equipment group,” the company will intensify R&D investment with heightened political responsibility and mission awareness, resolutely tackling “bottleneck” core technologies. This commitment aims to inject powerful momentum into the high-quality development of China’s power equipment manufacturing sector and the nation’s ambition to become a global leader in advanced equipment manufacturing—writing a new chapter of scientific and technological self-reliance and strength on China’s journey toward national rejuvenation.