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

In a 10kV power distribution system, the two most commonly used circuit breakers are vacuum circuit breakers and SF₆ circuit breakers. They are the core switchgear components of the medium-voltage distribution network, responsible for reliably opening and closing circuits under normal and fault conditions. The following is an introduction and comparison of these two types of circuit breakers:

It utilizes high vacuum as the arc extinguishing and insulation medium.

Working principle: When the contacts separate and an arc is generated, the metal vapor in the vacuum is ionized. When the current crosses zero, the metal vapor ions rapidly recombine and diffuse, restoring the medium strength quickly, thereby extinguishing the arc.

Main features:

 Advantages:

Strong arc extinguishing capability, fast opening and closing speed, long service life.

Small opening distance, compact structure, small volume.

No fire or explosion risk, environmentally friendly (medium is vacuum)

.Low maintenance workload, suitable for frequent operations.

 Disadvantages:

May generate overvoltage when breaking small inductive current, usually requires overvoltage protection devices.

Vacuum degree maintenance and detection are key.

Typical application: Widely used in 10kV distribution lines, industrial and mining enterprise substations, high-rise building power supply, wind and solar power boosting stations, etc., and is currently the absolute mainstream in the 10kV system.

It utilizes SF₆ gas as the arc extinguishing and insulation medium.

Working principle: SF₆ gas has excellent insulation and arc extinguishing performance. Under high-temperature electric arcs, it decomposes, absorbs energy, and when the current crosses zero, the decomposition products rapidly recombine and diffuse, restoring the medium strength, causing the arc to extinguish.

Main features:

 Advantages:

Excellent insulation and arc extinguishing performance, large breaking capacity.

Long electrical life, low noise.

Stable performance in indoor, outdoor, and harsh environments such as humid and polluted areas.

 Disadvantages:

SF₆ is a potent greenhouse gas under the Kyoto Protocol, with issues of leakage and recycling treatment.

High requirements for production processes and sealing, and higher prices.

Consideration of SF₆ gas liquefaction in low-temperature environments.

Typical application: In applications requiring high breaking capacity and environmental adaptability, such as underground substations in cities, coastal or polluted areas, and large industrial and mining enterprises' main step-down substations. In higher voltage levels, it is more common, but its application proportion is lower than vacuum circuit breakers in the 10kV field.

Vacuum circuit breakers, due to their advantages of environmental friendliness, compactness, maintenance-free, and cost-effectiveness, have become the standard configuration and preferred choice for the 10kV distribution system, occupying the vast majority of the market share.

SF₆circuit breakers, with their excellent breaking performance and environmental adaptability, still have their irreplaceable value in special and important application scenarios, but due to environmental pressure, their development is restricted.

Development trend: With increasingly strict environmental requirements, vacuum circuit breaker technology is constantly advancing, with continuous improvement in breaking capacity and other performance. Its dominant position will be further consolidated. At the same time, "SF₆-free" circuit breakers using environmentally friendly gases (such as dry air, nitrogen, etc.) are also under research and development and promotion.

Therefore, when asked about the commonly used circuit breakers in the 10kV distribution system, vacuum circuit breakers are the first to be mentioned, followed by SF₆circuit breakers.

VTZ-12 vacuum circuit breaker (special model of Tongzhong Electrical Co., Ltd.) produced by Shaanxi West Power Tongzhong Electrical Co., Ltd.is an indoor switchgear for rated voltage 12kV, AC 50/60Hz. It adopts a modular operating mechanism and is suitable for various industrial and mining enterprises, as well as power grid equipment. It can be used as a handcart unit for use with KYN28A-12 switchgear, or as a fixed unit with relevant mechanical interlocking, making it suitable for XGN2 and other fixed cabinets.