What is Vacuum Circuit Breaker: Working, Advantage & Its Applications

Today, circuit breakers are indispensable to minimise equipment damage and protect electrical networks. When comparing the diverse circuit breakers, Vacuum Circuit Breakers (VCBs) are worth special attention because of their work and benefits. This post is specially curated for those curious about ‘vacuum circuit breaker’, how it works, the pros of utilising VCB, and where or in what it is used. This blog covers all you need to learn about VCBs, such as how they are constructed, why they are used extensively in the electrical industry, and how they work.

What is Vacuum Circuit Breaker?

To begin with, let's answer the basic question: What is vacuum circuit breaker? VCB stands for vacuum circuit breaker, and in this type of circuit breaker, arc quenching takes place in the vacuum. VCBs are protection devices that aim to break the flow of extra currents that could result from a short circuit or overload, among other faults.

Vacuum breakers are frequently used in medium-voltage systems with circuits that carry moderate-voltage standards ranging from 1kV to 38kV. Another important characteristic of VCBs is that the arc extinguishing medium in these breakers is vacuum, which makes them much more effective and long-lasting than circuit breakers.

Construction of Vacuum Circuit Breaker

The design of vacuum circuit breakers is rather rigid, with only a few parts, making it the best in the circuit breaker market. Understanding the construction is the first step in understanding the vacuum circuit breaker's working principle.

• Fixed and Moving Contacts: These are from special alloys. They assist in breaking the arc.
• Vacuum Interrupter: This is the major section of the breaker in which the interruption of the arc takes place. The contacts are located inside the vacuum chamber, which is vitally important to the device's work.
• Operating Mechanism: The mechanism ensures that the right amount of force is applied to open and close the contacts.
• Insulating Enclosure: The whole construction is built within a closed insulating structure to shield it from exterior conditions.

The construction is very specialised, as the arc is to be interrupted as effectively as possible, requiring the least amount of wear and tear on the breaker.

VCB Working Principle

So, that was an introduction to what a vacuum circuit breaker is. Now, the next thing we will look at is the vacuum circuit breaker working principle. Vacuum circuit breaker operation depends on arc extinction in the vacuum. Here's a step-by-step breakdown of the VCB working principle:

• Fault Detection: In the case of an overload or short circuit, a fault is sensed.
• Contact Separation: The operating mechanism causes the movement of the contacts, either fixed or those in motion separator, to create an arc.
• Arc Formation: When the contacts are rendering separation, ionisation happens, and an arc is shaped. However, given that the contacts are situated within a vacuum environment, the arc is effectively suppressed.
• Arc Extinguishing: In a vacuum, there is no free electron or gas particle to maintain the arc between the electrodes. This leads to the immediate breaking of the arc when the contacts open by a small amount of space.
• Current Interruption: As soon as the arc is quenched, no current will flow through the circuit breakers, preventing the circuit from being damaged.

The vacuum circuit breaker's working principle effectively breaks a circuit in milliseconds, thus providing adequate protection as quickly as possible.

Read Also - Types of circuit breakers and their importance

Benefits of using Vacuum Circuit Breakers

Another fascinating aspect of vacuum circuit breakers is that they are commonly utilised in modern electrical systems because of the following vacuum circuit breaker advantages. 

Long Service Life

Given that vacuum interrupters are subjected to a very low amount of wear and tear arising from contact erosion, the VCBs can last a century or so without requiring much overhaul. Another advantage of this long service life is the ability to lower operational costs.

Efficient Arc Quenching

The arc almost disappears in these breakers. This makes it easy to protect the contacts and prevents accidents, thus reducing the time taken to repair.

Environmentally Friendly

Vacuum circuit breakers are environmentally preferable to other circuit breakers that use greenhouse gases such as sulphur hexafluoride. 

Compact Design

Since they are to be installed in small and restricted spaces, VCBs are lighter and more compact than older transformer designs. This makes them popular in industries where space is an important constraint, such as commercial real estate.

Low Maintenance

VCBs are less costly to operate since they almost never have arcing gases that need replacement frequently, and contact erosion is also minimal compared to traditional circuit breakers.

Application of Vacuum Circuit Breaker

Let's take a look at the key use of vacuum circuit breakers.

Industrial Applications

VCBs have found wide applications in different industries to protect motors, transformers, and other electrical utilities. Because they can withstand high currents and afford dependable protection, they are applicable in industries.

Power Plants

VCBs are fundamental components of power generation plants, acting as electric arc protectors for power grids safely and efficiently. Their application helps guarantee that any electrical problem is tended to as soon as possible, thus reducing the probability of power blackouts or equipment destruction.

Commercial Buildings

In commercial structures where power distribution for medium voltage is needed, VCBs safeguard electrical installations from overloading and short circuits. They are small and, therefore, easily applicable to building installations.

Read Also - Advantages of Circuit Breaker Test: Definition and Procedure Explained

Conclusion

Understanding vacuum circuit breakers and their working principles can help you appreciate why they are preferred in modern electrical systems. Vacuum circuit breakers' advantages are clear, from their efficient arc-quenching properties to their long service life. Their applications span industries, power plants, and commercial buildings, making them essential to today's electrical infrastructure.

For anyone looking to invest in reliable vacuum circuit breakers, Schneider Electric eShop offers premium-quality products that ensure safety and efficiency. Whether you're protecting an industrial facility or a commercial building, Schneider Electric has the right solutions for you.

Frequently Asked Questions

Q1. What is a vacuum circuit breaker, and how does it work?

Ans: A vacuum circuit breaker (VCB) is a circuit breaker where arc quenching occurs in a vacuum. The working principle involves separating the contacts in a vacuum chamber, which leads to the quick extinction of the arc, thus interrupting the current flow.

Q2. What are the main advantages of vacuum circuit breakers?

Ans: Some key vacuum circuit breaker advantages include a long service life, efficient arc quenching, compact design, low maintenance requirements, and environmental friendliness.

Q3. Where can I buy vacuum circuit breakers?

Ans: You can purchase high-quality vacuum circuit breakers from Schneider Electric eShop, which offers a wide range of electrical products suitable for various applications, including industrial and commercial use.