363kV 380kV 400kV 420kV Dead tank SF6 circuit breaker Original Manufacturer

During the normal operation and interruption processes of a circuit breaker, SF₆ gas can decompose, producing various decomposition products such as SF₄, S₂F₂, SOF₂, HF, and SO₂. These decomposition products are often corrosive, toxic, or irritating, and therefore require monitoring.If the concentration of these decomposition products exceeds certain limits, it may indicate abnormal discharges or other faults within the arc quenching chamber. Timely maintenance and handling are necessary to prevent further damage to the equipment and to safeguard personnel health.

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.

Focus on three core points: First, voltage matching, which must conform to the maximum operating voltage of the system (compatibility coefficient ≤1.05); second, customization of key parameters — the break spacing of 345kV equipment is reduced by 5%-8% compared with 363kV, and the voltage equalizing capacitor of 380kV equipment is increased by 8%-10%; third, the short-circuit breaking current shall be ≥50kA, and the third-party insulation coordination test must be passed.