Revolutionary 550 kV Capacitor-Free Arc-Quenching Circuit Breaker Debuts in China

Recently, a Chinese high-voltage circuit breaker manufacturer, in collaboration with numerous renowned enterprises, successfully developed a 550 kV capacitor-free arc-quenching chamber circuit breaker, which has passed the full suite of type tests on its first attempt. This achievement marks a revolutionary breakthrough in the interrupting performance of circuit breakers at the 550 kV voltage level, effectively resolving the long-standing “bottleneck” issue caused by reliance on imported capacitors. It provides strong technical support for building next-generation power systems and significantly contributes to clean energy transmission and China’s “Dual Carbon” goals (carbon peak and carbon neutrality).

As a critical component of power systems—often hailed as the “guardian of grid safety”—the arc-quenching capability of circuit breakers directly impacts grid stability. Traditional extra-high-voltage (EHV) circuit breakers rely on external capacitor banks to assist in arc interruption, resulting in complex structures, large physical footprints, and high operation and maintenance costs. Moreover, these capacitors have been entirely dependent on imports, leading to prolonged procurement cycles.

To address these challenges, the R&D team at the Chinese manufacturer leveraged internationally advanced arc simulation and measurement systems to conduct in-depth studies on how parameters such as puffer cylinder pressure, fluid temperature, flow velocity, and mass flow rate affect interrupting performance. Through multi-stage gas flow field optimization, they significantly enhanced breaking capability. Crucially, the team pioneered a capacitor-free arc-quenching chamber design, completely eliminating dependence on traditional capacitor banks.

The new 550 kV circuit breaker features a capacitor-free arc-quenching structure, substantially increasing the insulation distance to ground. Its coaxial design ensures mechanical simplicity and compactness. The unit supports cover-opening inspections, effectively avoiding risks associated with capacitor oil leakage or damage, thereby greatly improving equipment reliability. By removing integrated capacitors per phase, eliminating capacitor supports, and optimizing both moving and stationary end brackets, the design enhances assembly efficiency and quality while reducing reliance on imported core components. This innovation shortens manufacturing lead times and achieves full domestic control over the production process.

Looking ahead, the Chinese high-voltage circuit breaker manufacturer will continue to prioritize market demand, drive innovation-led development, and leverage synergies across industry–academia–research partnerships. The company remains committed to advancing landmark core technologies and building a world-class high-end equipment industrial cluster, contributing Chinese ingenuity to the global energy transition.