Two types of circuit breakers commonly used in 10kV distribution systems

The two commonly used circuit breakers in 10kV distribution systems are vacuum circuit breaker and sulfur hexafluoride (SF6) circuit breaker. The specific information is as follows:

I. Vacuum circuit breakers

1 Core features

Using a high vacuum environment as the insulation and arc extinguishing medium, the arc is only composed of metal vapor when the contacts are separated, and there is no ionized substance.

It has the advantages of small cutoff value, fast action, short arcing time, light volume, fireproof and explosion-proof, and is suitable for frequent operation.

2 Application advantages

High breaking capacity, can effectively protect the circuit from overload and short circuit.

Representative products include ABB's VD4 series and Schneider's HVX12 series.

II. Sulfur hexafluoride (SF6) circuit breakers

Core features

Using SF6 gas as the insulation and arc extinguishing medium, the insulation performance is 2.5~3 times that of air, and the arc extinguishing efficiency is high.

Adopting arc extinguishing technology combining thermal expansion and compressed air blowing, there is no cutoff phenomenon when breaking the current, avoiding operating overvoltage and extending the life of the equipment.

Application advantages

Applicable to high voltage and high current scenarios, especially for sensitive equipment such as capacitor banks.

The contact burns slightly and the maintenance cycle is long.

Ⅲ. Selection basis

Vacuum circuit breaker focus more on frequent operations and space-constrained scenarios (such as urban distribution networks).

SF6 circuit breakers are suitable for occasions with extremely high requirements for insulation and arc extinguishing performance (such as high-voltage substations).