What is Circuit Breaker?
Definition of circuit breaker: - Electrical
circuit breaker is a switching device which can be operated manually as well as
automatically for controlling and protection of electrical power system
respectively. As the modern power system deals with huge currents, the special
attention should be given during designing of circuit breaker to safe
interruption of arc produced during the operation of circuit breaker. This was
the basic definition of circuit breaker.
Introduction to Circuit Breaker
The modern power system deals with huge power
network and huge numbers of associated electrical equipment. During short
circuit fault or any other types of electrical fault these equipment as well as
the power network suffer a high stress of fault
current in them which may damage
the equipment and networks permanently. For saving these equipment and the
power networks the fault current should be cleared from the system as quickly
as possible. Again after the fault is cleared, the system must come to its
normal working condition as soon as possible for supplying reliable quality
power to the receiving ends. In addition to that for proper controlling of
power system, different switching operations are required to be performed. So
for timely disconnecting and reconnecting different parts of power system
network for protection and control, there must be some special type of
switching devices which can be operated safely under huge current
carrying condition. During interruption of huge current, there would be
large arcing in between switching contacts, so care should be taken to quench these
arcs in circuit breaker in safe manner. The circuit breaker is the special
device which does all the required switching operations during current
carrying condition. This was the basic introduction to circuit breaker.
Working Principle of Circuit Breaker: ( सर्किट ब्रेकर का
The circuit breaker mainly consists of fixed
contacts and moving contacts. In normal "on" condition of circuit
breaker, these two contacts are physically connected to each other due to
applied mechanical pressure on the moving contacts. There is an arrangement
stored potential energy in the operating mechanism of circuit breaker which is
realized if switching signal given to the breaker. The potential energy can be
stored in the circuit breaker by different ways like by deforming metal spring,
by compressed air, or by hydraulic pressure. But whatever the source of
potential energy, it must be released during operation. Release of potential
energy makes sliding of the moving contact at extremely fast manner. All
circuit breaker have operating coils (tripping coils and close coil), whenever
these coils are energized by switching pulse, the plunger inside them displaced. This operating coil plunger is
typically attached to the operating mechanism of circuit breaker, as a result
the mechanically stored potential energy in the breaker mechanism is released
in forms of kinetic energy, which makes the moving contact to move as these
moving contacts mechanically attached through a gear lever arrangement with the
operating mechanism. After a cycle of operation of circuit breaker the total
stored energy is released and hence the potential energy again stored in the
operating mechanism of circuit breaker by means of spring charging motor or air
compressor or by any other means. Till now we have discussed about mechanical working
principle of circuit breaker. But there are electrical characteristics of a
circuit breaker which also should be considered in this discussion of operation
of circuit breaker.
Discussion on electrical principle of circuit
breaker.
The circuit breaker has to carry large rated
or fault power. Due to this large power there is always dangerously high arcing
between moving contacts and fixed contact during operation of circuit breaker.
Again as we discussed earlier the arc in circuit breaker can be quenching
safely if the dielectric strength between the current carrying contacts of
circuit breaker increases rapidly during every current zero crossing of the
alternating current. The dielectric strength of the media in between contacts
can be increased in numbers of ways, like by compressing the ionized arcing
media since compressing accelerates the deionization process of the media, by
cooling the arcing media since cooling increase the resistance of arcing path
or by replacing the ionized arcing media by fresh gasses. Hence a numbers of
arc quenching processes should be involved in operation of circuit
breaker.
Types of Circuit Breaker (सर्किट ब्रेकर के प्रकार )
According different criteria there are different types of circuit breaker.
According to their arc quenching media the
circuit breaker can be divided as-
Oil circuit breaker.
Air circuit breaker.
SF6 circuit breaker.
Vacuum circuit breaker.
According to their services the circuit
breaker can be divided as-
Outdoor circuit breaker
Indoor breaker.
According to the operating mechanism of
circuit breaker they can be divided as-
Spring operated circuit breaker.
Pneumatic circuit breaker.
Hydraulic circuit breaker.
According to the voltage level of installation
types of circuit breaker are referred as-
High voltage circuit breaker.
Medium voltage circuit breaker.
Low voltage circuit breaker.Feedbacks From Readers Are Most Welcomes.....in comment section
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