Wednesday, 1 April 2020

Oil Circuit Breaker- Working Principle, Construction, Types, Advantages

• Circuit Breaker is device used to break circuit during load in on and due to load current flow in the circuit.
• Oil Circuit breaker is breaker used to break the circuit when abnormal voltage appears and it will protects electrical equipments from abnormal voltage.
• Oil Circuit breaker is used for two purposes one is arc quenching medium and other is for cooling purpose.

Oil Circuit Breaker
Oil Circuit Breaker 

Working Principle Of Oil Circuit Breaker

• Oil Circuit breaker is used as arc quenching medium and for cooling purpose.
•  As the time of arc oil absorbs heat and split into ions and molecules and releases gases hydrogen, ethane etc.
• Which releases high amount of hydrogen gas which leads to turbulence (force) of the oil the length of the arc increases and resistance of the arc decreases but as we know resistance is inversely proportional to the current finally arc will be extinction.
• The arc extinction is occured mainly by two purposes
•  Firstly the hydrogen gas has high heat conductivity and cools the arc thus aiding the de-ionization of the medium between the contact.

• Second the gas sets up turbulence in the oil and forces it into the space between contacts, thus eliminating the arcing products from the arc path.
Thus arc extinguish and circuit current interrupts.

Construction of Oil Circuit Breaker

Construction of Oil Circuit Breaker

• It consists of current carrying contacts enclosed in a strong weather tight earth tank.
• That tank is filled with oil that is transformer oil. The oil acts as arc extinguishing medium and as an insulator between the live part and earth.
•  At the top of oil, air is filled in the tank which acts as cushion to control the displaced oil on the formation of gas around the arc.
• Oil Circuit Breaker consists gas outlet which is fitted in the tank cover for the removal of the gases.

Types of Oil Circuit Breaker

There are main two types of the oil Circuit breaker are following

1. Bulk oil Circuit breaker
Bulk Oil Circuit Breaker is again classified into two types
a. Plain break oil Circuit breaker
b. Arc Control Circuit Breaker

Bulk oil Circuit breaker
Bulk oil Circuit breaker

Minimum Oil Circuit Breaker
Minimum Oil Circuit Breaker

Advantages Of Oil Circuit Breaker

• Oil has good insulating properties which keeps arc formation to a minimum when the breaker is open or closed.
• Oil has high dielectric strength.
• Oil absorbs arc energy while decomposing.
• Good cooling property of the gas formed due to the decomposition.
• It acts as an insulator between the live parts and earth.

Disadvantages of Oil Circuit Breaker

• It takes long arcing time.
• It do not permit high speed of interrupt.
• Arc interruption control can be obtained only by increasing length of arc.


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