Hello Electrical Engineers. Today in my very first article I
am going to introduce you to the subject of the Switchgear as well as
protection, because both are closely related to each other.
First of all the question arises is that what actually is
Switchgear? A Switchgear can be described as an apparatus which is used for
switching, controlling and protection the electrical equipments and circuits.
Switchgear equipment is essentially concerned with switching
and interrupting currents either under normal conditions or abnormal
conditions. For example a tumbler switch with ordinary fuse which is used to
protect the equipments in homes is the simplest form of switchgear. For higher
rating H.R.C. fuses (High rupturing capacity) are used in conjunction with switch
may serve the purpose of controlling and protecting the circuit.
However different types of switchgear are used for different
capacity of electrical systems. The tumbler switch or H.R.C. fuse cannot be
used for High Voltage systems, because their replacements takes time and they
are not capable of interrupting large fault currents.
In order to overcome above disadvantage, Circuit Breakers
are developed. A Circuit Breaker is switchgear which can open or close
electrical circuit under normal as well as abnormal conditions and it can also
be operated automatically or manually.
Some of essential features of switchgear
·
High reliability: When fault occurs on
any part of power system, the switchgear must operate to isolate the faulty
section from the rest of circuit
·
Complete Discrimination: When fault
occurs in power system or any section of power system, the switchgear must be
able to discriminate between faulty section and healthy section
·
Quick operation: When fault occurs in an
power system the switchgear must operate as quickly as possible so that no
damage is done to the equipments connected to the same line
·
Provision for manual control: Although
switchgear operates automatically, there should be provision provided to
operate them manually as well.
·
Provision for instruments: There must be
provision for instruments which may be required. They can be ammeters,
voltmeters, etc
Following are the types of switchgear equipments
·
Relays
·
Switches
·
Fuses
·
Circuit Breaker
I hope after referring above article you understood what are
switchgear and its function. In the next article we will go through one by one the
types of switchgear, their types, construction, function, etc.
