What is a circuit breaker
A circuit breaker is a type of switching device which can be used for protecting the electrical equipment in a power system, it does the interruption of electricity if any fault is detected.
Air circuit breaker
Air circuit breaker is a different type of circuit breaker in which air is used as the arc quenching medium and these type of circuit breaker is used in low voltage range and the voltage range is up to 15Kv and its rupturing capacity is 500 MVA the air circuit breaker is classified depending upon their types of air breaking method
Types of air circuit breaker
- Normal air circuit breaker
- Air blast circuit breaker
- Axial blast air circuit breaker
- Cross blast air circuit breaker
- Radial blast air circuit breaker
Oil circuit breaker
In an oil circuit breaker oil is used as an arc quenching medium, mostly preferred oil is mineral oil, it has better insulation property than air, in many countries air circuit breaker is replaced by oil circuit breaker and the use of air circuit breaker is reduced because the oil circuit breaker provides more ease of use and it has economical advantage too.
Types of oil circuit breaker
- Bulk oil circuit breaker
- Medium oil circuit breaker
- Self-blast oil circuit breaker
- Forced blast oil circuit breaker
What is an arc voltage
Arc voltage is the voltage needed for maintaining an arc. when the breaker contacts open an arc is formed between the contacts of the circuit breaker, and the voltage which appears during the arcing period across the contacts of the breaker is called as the arc voltage
Difference between oil and air circuit breaker
The major difference between these circuit breakers are in an air circuit breaker natural atmospheric air is used as the arc quenching medium while in case of oil circuit breaker the oil acts as an arc extinguishing medium
Due to the development of the oil circuit breaker, the medium voltage air circuit breaker is replaced by the oil circuit breaker
But in some countries air circuit breaker is still in use because it is safer than the oil circuit breaker, there is no chance of fire so in many countries air circuit breaker is still preferred in place of oil circuit breaker
Air circuit breaker works at the high atmospheric pressure of the air. in some countries, ACB replaces oil circuit breaker for medium voltage level and the ACB rating voltage is up to 15KV, for higher voltage level oil circuit breaker, can be used
Advantages of air circuit breaker
- Low maintenance is needed
- Arc quenching process is very fast
- No risk is involved in this, as it uses air as an arc quenching medium
- The operation speed is very fast so due to this only small amount of heat is generated
- The protection offered by this circuit breaker is reliable because it has very quick response
Disadvantages of air circuit breaker
- It can’t be used for higher voltage applications
- Air has lower arc extinguishing properties
- It has a high capacity air compressor
Advantages of oil circuit breaker
- The oil has high dielectric strength and after the arc extinguishing it provides insulation between the contact
- It can be used for high voltage application
- Hydrogen gas provides better cooling properties
Disadvantages of oil circuit breaker
- The oil in the circuit breaker may cause a fire.
- Dielectric strength of the oil decreases due to the generated carbon particles
- Maintenance is high