What are the commonly used high-voltage circuit breakers? The circuit breaker manufacturer tell you!

Oil circuit breaker

A circuit breaker that uses transformer oil as the arc extinguishing medium and the arc gap insulation medium after contact breaking is called a low oil circuit breaker; The circuit breaker that uses transformer oil as the arc extinguishing medium, the arc gap insulation medium after contact breaking, and the insulation medium between the live part and the grounding shell becomes a multi oil circuit breaker.

Working principle: When the oil circuit breaker opens the circuit, as long as the current in the circuit exceeds 0.1A and the voltage exceeds tens of volts, an arc will appear between the moving and stationary contacts of the circuit breaker, and the current can continue to flow through the arc. Only when the contacts are separated by a sufficient distance can the arc extinguish before the circuit is opened. When the 10kV low oil circuit breaker breaks 20KA, the arc power can reach over 10000 kilowatts, and the temperature of the arc column generated between the circuit breaker contacts can reach 6000 to 7000 degrees Celsius, even exceeding 10000 degrees Celsius.

Compressed air circuit breaker

A circuit breaker that uses high-pressure air to blow an arc and extinguish it. During its operation, high-speed airflow blowing produces a strong heat dissipation and cooling effect on the arc column, causing it to undergo thermal ionization and rapidly weaken or even disappear. After the arc is extinguished, the arc gap is replenished with fresh compressed air, and the dielectric strength quickly recovers.

Due to the emergence of sulfur hexafluoride circuit breakers with simple structure, good arc extinguishing performance, and long electrical life, the range of use of compressed air circuit breakers has been reduced. However, in some high-altitude and cold regions such as northern Europe, due to the liquefaction of SF6 gas and the decrease in breaking capacity (by about 20%), some countries are still using compressed air circuit breakers in high-voltage and ultra-high voltage power grids. In addition, large capacity generator circuit breakers require large breaking capacity and quick action, and compressed air circuit breakers are now widely used.

Vacuum circuit breaker

The "vacuum circuit breaker" is named after its high vacuum in both the arc extinguishing medium and the insulation medium in the contact gap after arc extinguishing; It has the advantages of small size, light weight, suitable for frequent operation, and arc extinguishing without maintenance, and is widely used in distribution networks. Vacuum circuit breakers are indoor power distribution devices in a 3~10kV, 50Hz three-phase AC system, which can be used for the protection and control of electrical equipment in industrial and mining enterprises, power plants, and substations. They are particularly suitable for use in places that require oil-free, less maintenance, and frequent operation. Circuit breakers can be configured in central cabinets, double-layer cabinets, and fixed cabinets to control and protect high-voltage electrical equipment.

Sulfur hexafluoride circuit breaker

Sulfur hexafluoride circuit breaker is an oil-free switchgear that uses SF6 gas as the insulation medium and arc extinguishing sulfur hexafluoride circuit breaker medium. Its insulation performance and arc extinguishing characteristics are significantly higher than oil circuit breakers. Due to its high price and high requirements for the application, management, and operation of SF6 gas, its application in medium voltage (35, 10KV) is not widespread enough, mainly applied to voltage levels above 110kV.