What is Current Chopping in Circuit Breaker?

Current chopping in a circuit breaker refers to the phenomenon where the current is intentionally interrupted before reaching natural current zero. This occurrence is particularly notable in Vacuum Circuit Breakers and Air Blast Circuit Breakers, while it is absent in Oil Circuit Breakers. Current chopping is most pronounced during the switching of a Shunt Reactor or an unloaded Transformer.

In the context of a reactor, the energy stored in its inductance is transferred to a capacitor.

What is Vacuum Circuit Breaker?

A vacuum circuit breaker is a type of breaker that utilizes a vacuum as the medium to extinguish electrical arcs. Within this circuit breaker, there is a vacuum interrupter that houses the stationary and mobile contacts in a permanently sealed enclosure. When the contacts are separated in a high vacuum environment, the electrical arc is effectively extinguished. As an illustration, when the contacts of a circuit breaker are opened within a vacuum environment, the interruption takes place precisely at the moment of the initial current reaching zero. This results in the dielectric strength between the contacts rapidly increasing at a rate thousands of times greater than what is achieved with alternative types of circuit breakers.

Table of Content

  • Vacuum Circuit Breaker
  • Types
  • Construction
  • Working Principle
  • Working
  • Tests
  • Vacuum Circuit Breaker Vs Vacuum Contact Unit
  • Applications
  • Advantages and Disadvantages

Similar Reads

What is Vacuum Circuit Breaker?

A vacuum circuit breaker is a type of breaker that employs a vacuum as the medium for extinguishing arcs. The permanently sealed vacuum interrupter of this circuit breaker houses both the fixed and movable contacts. The separation of contacts within a high vacuum ensures the extinction of the arc. This device is used to prevent the unexpected current which is caused because of the short circuit in any system. Also it interrupts the voltage in some applications .Basically arc quenching takes place in this in the vacuum medium. Insulating medium is high for the arc extinction as compared to the other circuit breakers....

Types of Vacuum Circuit Breaker

Some types of Vacuum Circuit Breaker are as follows:...

Construction of Vacuum Circuit Breaker

The construction of a vacuum circuit breaker is easy when compared to other types of circuit breakers. It primarily consists of three key components: fixed contacts, moving contacts, and an arc shield located within the arc interruption chamber. The outer casing of the vacuum circuit breaker is crafted from glass, which enables external inspection of the breaker’s condition after operation. If the glass changes from its original mirrored appearance to a milky one, it signals a loss of vacuum within the breaker. The fixed and moving contacts are housed within the arc shield, and during the sealing process, the vacuum interrupter is maintained at approximately 10^-6 torr. The extent of movement for the circuit breaker’s moving contacts typically ranges from 5 to 10 mm, depending on the operating voltage. The most important is the design of the metallic below because the durability of this device depends on the repeated operations performed....

Working Principle of Vacuum Circuit Breaker

When the contacts of the circuit breaker are separated within the vacuum environment, typically ranging from 10^-7 to 10^-5 torr, an arc is generated between the contacts through the ionization of metal vapors emitted by the contacts. So as the fault occurs in the system , contact of the breaker is moved apart and arc is developed between this....

Working of Vacuum Circuit Breaker

In the event of a fault in the system, the circuit breaker’s contacts are separated, leading to the formation of an electrical arc between them. As the current-carrying contacts are pulled apart, the temperature at their connecting points becomes significantly high, resulting in ionization. This ionization process fills the contact space with positive ion vapors emitted from the contact material....

Tests of Vacuum Circuit Breaker

Some of the test perform of the Vacuum Circuit Breaker are:...

What is Current Chopping in Circuit Breaker?

Current chopping in a circuit breaker refers to the phenomenon where the current is intentionally interrupted before reaching natural current zero. This occurrence is particularly notable in Vacuum Circuit Breakers and Air Blast Circuit Breakers, while it is absent in Oil Circuit Breakers. Current chopping is most pronounced during the switching of a Shunt Reactor or an unloaded Transformer....

Difference between Vacuum Circuit Breaker and Vacuum Contact Unit

Vacuum Circuit Breaker Vacuum Contact Unit A Vacuum Circuit Breaker is a specialized circuit breaker designed to safeguard high-voltage systems from potential damage. A vacuum contactor is a device capable of enduring numerous operations with a strong mechanical lifespan. They are commonly employed for voltage levels ranging between 3 kV and 36 kV. The necessary ratings those of vacuum contactors, reaching values of 200 A or 630 A at voltages up to 15 kV. The loads contain transformers, capacitors, sizable motors, generators, or distribution feeders. The continuity of the process aligns with the time required for fuse replacement. Switching occurrences are infrequent. Switching occurrences are frequent....

Applications of Vacuum Circuit Breaker

The vacuum circuit breaker, known as VCB, finds application in various industrial settings as a high-speed switching device. These circuit breakers are well-suited for systems operating within the voltage range of 11V to 33 kV. They are commonly paired with static overcurrent relays to achieve a total clearance time of less than 40 milliseconds in the case of phase-to-phase faults. VCBs are employed in high-voltage circuits, generators, and electrical substations. They are particularly useful for interrupting both double earth faults and phase currents. These breakers are the choice when rapid and high-frequency switching is required, and they also serve in railway applications for tasks like electric supply switching and managing traction current. The vacuum circuit breakers play a significant role in switching motor drives in various applications....

Advantages and Disadvantages of Vacuum Circuit Breaker

The advantages and disadvantages of the circuit breaker are given below:...

Properties of Contact Material

High Density High Electrical conductivity of the material so that normal load current can pass easily High arc withstand ability of the material Current chopping level must be low....

Conclusion

The using of vacuum circuit breakers has been increasing due to their dependable performance in medium voltage networks. Additionally, they abolish the requirement for costly switchgear, particularly crucial in low or high-voltage networks. Vacuum circuit breakers are engineered to automatically open and close in response to signals from sensors. Vacuum circuit breakers are primarily employed for medium voltage applications, typically in the range of 11 KV to 33 KV....

FAQs on Vacuum Circuit Breaker

What is the definition of Vacuum Circuit Breaker?...