Why use the VCB at High Transmission System ? Why can’t use ACB?

What is Air Circuit Breaker?

Air Circuit Breakers (ACBs) prevent overloads & short circuits by using air. Faults stop current flow. Broken connections form an arc. Compressed air or rapidly swinging the contacts into a small chamber blows out the arc in air circuit breakers.

This circuit breaker uses atmospheric pressure.

Unlike fuses, circuit breakers can be reset manually or automatically. Circuit breakers are remote-controlled, unlike fuses.

What is Vacuum Circuit Breaker?

Vacuum circuit breaker is referred to as VCB. The arc is quenched by vacuum medium in this kind of circuit breaker.


Vacuum is employed in VCB because it has a far higher dielectric strength than any other form of medium.

Compared to other mediums, the vacuum is the best dielectric dielectric for extinct employing the arc.

Vacuum circuit breakers are used for switching in addition to the protection of the system components, hence they must be extremely quick to trip in the event of a malfunction so that no equipment damage is done. Thus, these breakers are crucial at network incomers and interconnectors.

Why is the VCB used in High Transmission Systems?

The vacuum circuit breaker, also known as a VCB, is widely utilised in high transmission systems due to its superior arc-quenching capabilities & reliable switching performance.

Moreover, this type of breaker is also known as a VCB. As a result of its capacity to withstand fault current levels of up to 100 kA, it is suitable for use in applications that demand for a significant quantity of power.

A vacuum circuit breaker, also known as a VCB, is superior in terms of dependability and productivity when compared to an air circuit breaker, also known as an ACB. This is particularly accurate at higher voltage values. It also has a quicker response time, which leads to an improvement in safety, and because of its improved arc-quenching capability, it is less likely to trip accidently on false alarms. Both of these factors contribute to an improvement in the overall level of safety.

A VCB also has a longer life length than an ACB does, which makes it an alternative that is more cost-effective to use.

In contrast to air, vacuum possesses a higher capacity to extinguish electrical arcs, because the electric strength of the die in VCB is equivalent to eight(8) times that of air, VCB is a very popular choice for electronic circuits.

These breakers implement the high-resistance intrusion principle in both the high-temperature vacuum interrupter (also known as an HT breaker) and the low-temperature air interrupter (also known as an LT breaker).

As a consequence of the significantly increased dependability of vacuum bottles in contrast to ACB. In addition, ACB have a routine maintenance that is significantly more frequent than VCB, while VCB have an overall maintenance schedule that is significantly less frequent.

It is significantly more likely that VCB will be effective in carrying out the specified number of operations. Arc chutes, in addition to having a lot of other advantages, do not present any difficulties. The contacts are housed within the bottles themselves, which are where they can be found. Because of this, there is no dirt or any other kind of problem.