What are the two most commonly used circuit breakers in a 10kV power distribution system?

In 10kV power distribution systems, two types of circuit breakers are commonly used: vacuum circuit breakers and SF6 circuit breakers. These two types differ in structure, working principle, and application, but both are important protection and control devices in power distribution systems. Vacuum circuit breakers utilize vacuum-sealed arc-extinguishing technology and are characterized by low current-carrying capacity. In a vacuum circuit breaker, the contacts are sealed within a vacuum tube; this environment effectively suppresses arc generation and ensures the circuit breaker's performance and lifespan. SF6 circuit breakers, on the other hand, utilize SF6 gas for arc extinguishing and insulation, and are characterized by high current-carrying capacity. SF6 gas has excellent insulation and arc-extinguishing properties, enabling arc extinguishing under high voltage and high current conditions.

Vacuum Circuit Breaker:

The contacts of a vacuum circuit breaker disconnect the circuit within a high-vacuum arc-extinguishing chamber. The insulating and arc-extinguishing media used are both high-vacuum air. The arc-extinguishing chamber contains virtually no ionizable substances; under any circumstances, when the contacts separate, the arc path between them consists solely of the metal vapor of the contact material.

The advantages of vacuum circuit breakers include: small contact gap, fast operation; short arcing time, rapid arc extinguishing; small size, light weight, fire and explosion resistant; and suitability for frequent operation.

Integral Cast-in-Place Pole

1. Upper Outlet Terminal
2. Vacuum Interruptor Chamber
3. Cast-in-Place Pole Housing
4. Moving Outlet Rod
5. Lower Outlet Terminal
6. Flexible Connection
7. Contact Pressure Spring
8. Insulating Pull Rod
9. Pole Fixing Insert
10. Operating Mechanism Connection

Sulfur hexafluoride (SF6) circuit breakers:

SF6 circuit breakers use sulfur hexafluoride gas as both the insulating and arc-extinguishing medium. Sulfur hexafluoride possesses superior insulation and arc-extinguishing capabilities; its insulation capacity is approximately 2.5 to 3 times higher than that of air. Most SF6 circuit breakers employ an arc-extinguishing principle based on a combination of thermal expansion and compressed gas-assisted blowing. This technology has been widely and maturely applied in the high-voltage switchgear field. It features smooth breaking characteristics and does not exhibit current-cutting phenomena during interruption, thus preventing operational overvoltages and avoiding damage to capacitor bank lifespan.

After interruption, the contact burn-off of SF6 circuit breakers is relatively minor, extending maintenance cycles and making them suitable for frequent operation.

1. Upper and lower cable outlets
2. Insulating sleeve
3. Nozzle
4. Moving main contact
5. Moving arc outlet
6. Stationary arc contact
7. Stationary main contact
8. Insulating pull rod
9. Explosion-proof membrane
10. Upper air chamber
11. Lower air chamber

Selection of Vacuum Circuit Breakers and SF6 Circuit Breakers

When selecting a circuit breaker, the specific requirements of the power distribution system and operating conditions must be considered. For example, vacuum circuit breakers can be selected for applications requiring frequent operation and with low current-breaking capacity requirements; SF6 circuit breakers can be selected for applications requiring high current breaking capacity and high current-breaking capacity requirements.

In summary, vacuum circuit breakers and SF6 circuit breakers are commonly used circuit breaker types in 10kV power distribution systems. Selecting the appropriate type based on specific requirements can ensure the safe and stable operation of the power distribution system.

About Us

Shaanxi Huadian, with its superior vacuum circuit breakers and SF6 circuit breakers, builds a reliable, efficient, and intelligent safety barrier for the modern power grid. We are not only a manufacturer of switchgear, but also a guardian of the stable operation of the power system.

Vacuum Circuit Breaker Series: Ultimate Breaking Capacity, Exceptional Lifespan

Deep Arc Extinguishing Technology: Utilizes an advanced vacuum arc-extinguishing chamber, exceeding industry standards in breaking capacity, with no explosion risk and easy maintenance.

Long Mechanical Life: Breaks through 10,000 mechanical operation cycles, meeting the needs of high-frequency operation scenarios.

Environmentally Friendly and Energy-Saving: Zero greenhouse gas emissions, aligning with the green power grid development concept.

SF6 Circuit Breaker Series: Superior Insulation, Rock-Stable Performance

Superior Insulation Performance: Sulfur hexafluoride gas provides superior dielectric strength, adapting to various harsh environments.

Ultra-Large Capacity Breaking Capacity: Meets the core needs of the main power grid.

Intelligent Monitoring System: Integrates digital monitoring units, providing real-time feedback on equipment status, enabling predictive maintenance.

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