Medium-voltage circuit breakers are crucial equipment in power systems, providing safe and reliable circuit breaking and closing operations. Here are several common types of medium-voltage circuit breakers:

I. Vacuum Circuit Breaker (VCB)

• Working Principle: It utilizes the high vacuum degree in a vacuum chamber to extinguish the arc, thereby achieving circuit breaking and closing.
• Advantages:
  • Excellent electrical performance, capable of quickly interrupting circuits.
  • Good pollution resistance and durability, suitable for harsh environments.
  • Simple structure, easy to maintain.
• Applications: Widely used in high-voltage power systems, especially in situations requiring frequent operations.

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II. SF6 Gas Circuit Breaker

• Working Principle: It uses SF6 gas as the arc-extinguishing medium. When an arc is generated, the SF6 gas rapidly decomposes and absorbs arc energy, thereby extinguishing the arc.
• Advantages:
  • Strong arc-extinguishing capability and stable performance.
  • Wide application range, adaptable to different working environments.
• Note: SF6 gas is a potent greenhouse gas with potential environmental impacts. Special attention to environmental protection is required during use and disposal.
• Applications: Widely applied in high-voltage power systems, particularly in situations requiring high reliability and stability.

III. Oil Circuit Breaker

• Working Principle: It uses transformer oil as the arc-extinguishing and insulating medium. When an arc is generated, the oil rapidly decomposes and produces a large amount of gas, thereby extinguishing the arc.
• Advantages:
  • Effective arc-extinguishing, strong breaking capacity.
  • High insulating performance and good safety.
• Disadvantages:
  • Large oil volume, difficult to maintain.
  • Risk of fire and explosion hazards.
• Applications: Although still used in high-voltage power systems, oil circuit breakers are gradually being replaced by other types of circuit breakers due to their disadvantages.

IV. Air Circuit Breaker

• Working Principle: It utilizes the natural extinction principle of arcs in air to break the circuit. When an arc is generated, the molecules in the air rapidly ionize and absorb arc energy, thereby extinguishing the arc.
• Advantages:
  • Low price, stable performance.
  • Simple operating mechanism, easy to maintain.
• Disadvantages:
  • Poor electrical performance, susceptible to environmental influences.
  • Less used in high-voltage power systems.
• Applications: Mainly used for distribution and protection in medium and low-voltage power systems.

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V. Other Types of Medium-voltage Circuit Breakers

Besides the above-mentioned common types of medium-voltage circuit breakers, there are also special types such as permanent magnet circuit breakers and encapsulated circuit breakers. These circuit breakers have their unique characteristics, advantages, and application scenarios in terms of structure, working principle, and performance.

In summary, there are various types of medium-voltage circuit breakers, each with its unique advantages, disadvantages, and application scenarios. When selecting a medium-voltage circuit breaker, comprehensive consideration should be given based on specific application requirements, working environment, and electrical requirements to ensure the selection of the most suitable circuit breaker type.

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