120kV 168kV 204 kV Tank Type Vacuum Circuit Breaker(VCB)

1. Their core difference is arc-extinguishing media: Vacuum breakers use high vacuum (10⁻⁴~10⁻⁶Pa) for insulation and arc extinction; SF₆ breakers rely on SF₆ gas, which adsorbs electrons well to quench arcs.
2. In voltage adaptation: Vacuum breakers fit medium-low voltages (10kV, 35kV; some up to 110kV), rarely 220kV+. SF₆ breakers suit high-ultra high voltages (110kV~1000kV), mainstream for ultra-high voltage grids.
3. For performance: Vacuum breakers extinguish arcs fast (<10ms), have 63kA~125kA breaking capacity, suit frequent use (e.g., power distribution) with long life (>10,000 cycles). SF₆ breakers excel in stable large/inductive current breaking but work less frequently, needing insulation recovery time post-extinction.
4. Compared to SF6 gas circuit breakers, vacuum circuit breakers can achieve zero greenhouse gas emissions and are more environmentally friendly because the arc extinguishing device does not contain any gas

The leakage rate of SF₆ gas must be controlled at an extremely low level, typically not exceeding 1% per year. SF₆ gas is a potent greenhouse gas, with a greenhouse effect 23,900 times that of carbon dioxide. If a leak occurs, it can not only cause environmental pollution but also lead to a decrease in the gas pressure within the arc quenching chamber, affecting the performance and reliability of the circuit breaker.

To monitor the leakage of SF₆ gas, gas leakage detection devices are typically installed on tank-type circuit breakers. These devices help to promptly identify any leaks so that appropriate measures can be taken to address the issue.

Integral Tank Structure：

• Integral Tank Structure: The breaker's arc quenching chamber, insulating medium, and related components are sealed within a metal tank filled with an insulating gas (such as sulfur hexafluoride) or insulating oil. This forms a relatively independent and sealed space, effectively preventing external environmental factors from affecting the internal components. This design enhances the insulation performance and reliability of the equipment, making it suitable for various harsh outdoor environments.

Arc Quenching Chamber Layout：

• Arc Quenching Chamber Layout: The arc quenching chamber is typically installed inside the tank. Its structure is designed to be compact, enabling efficient arc quenching within a limited space. Depending on different arc quenching principles and technologies, the specific construction of the arc quenching chamber may vary, but generally includes key components such as contacts, nozzles, and insulating materials. These components work together to ensure that the arc is quickly and effectively extinguished when the breaker interrupts the current.

Operating Mechanism：

• Operating Mechanism: Common operating mechanisms include spring-operated mechanisms and hydraulic-operated mechanisms.

• Spring-Operated Mechanism: This type of mechanism is simple in structure, highly reliable, and easy to maintain. It drives the opening and closing operations of the breaker through the energy storage and release of springs.

• Hydraulic-Operated Mechanism: This mechanism offers advantages such as high output power and smooth operation, making it suitable for high-voltage and high-current class breakers.