Switchgear is an apparatus which is employed for switching, controlling and protecting electrical circuits and equipment. the need of electrical power has increased tons , so so as to urge endless power supply. power grid must be shielded from large faults and supply protection to machinery and devices. For the continuity of the facility supply machinery like generators and motors are switched on and off repeatedly and therefore the means provide to realize this is often called switchgear.A device that’s wont to switch, control and protect the circuits also as devices. this is often anxious about switching also as interrupting currents under different operating conditions like normal or abnormal. In an electrical power grid , it’s an appointment of electrical disconnect switches, circuit breakers, fuses which are wont to protect, control & separate device .
Switchgear includes switching & protecting devices like fuses, switches, relays, circuit breakers, etc. This device allows operating devices like electrical equipment, generators, distributors, transmission lines, etc. Once the short occurs within the facility system, then an enormous current will flow through the devices. in order that the equipment are often damaged & the interruption will occur to the operators. to beat this problem, it’s wont to detect the fault within the power grid . during this way, this is often works to guard the equipment from the damage.
Types of switchgear:
Low Voltage Switchgear (LV):
The power system which deals up to 1KV is named as LV or low voltage switchgear. this type of kit mainly includes switches, LV circuit breakers, HRC fuses, earth leakage (EL) circuit breakers, offload electrical isolators, MCBs (miniature circuit breakers) and MCCBs (molded case circuit breakers), etc.
Medium Voltage Switchgear (MV):
The power system which deals up to 36 kV is named MV (medium voltage switchgear). These are available in several types like without metal enclosure outdoor type, metal-enclosed indoor & outdoor type, etc. this type of kit includes substation devices like minimum oil CBs, bulk oil CBs, SF6 gas-insulated, air magnetic, gas-insulated, vacuum, etc.The disruption medium of this sort of switchgear are often vacuum, SF & oil. the most condition of this sort of power network is to interrupt off current throughout faulty conditions during this system. this is often capable of ON/OFF operation, interruption of short current, capacitive current switching, inductive current switching and utilized in some special applications.
High Voltage Switchgear (HV):
The power system which deals above 36KV is named HV (high voltage) switchgear. When the extent of voltage increases then the arcing are going to be generated because the switching operation is extremely high. As a result, during the designing of this equipment, special care has got to be taken. the most component of this equipment is that the High Voltage (HV) breaker .Therefore HV breaker must include some safe & reliable operation features. The switching operation of the HV circuit is extremely rare. Usually, these CBs remain at ON state and may be worked after a while . Consequently, these must be reliable to form certain secure operations when required.
Classification Of switchgear
- The current rating
- Interrupting rating
- Voltage class- low voltage (less than 1000volts)
Medium voltage (1000 – 36000 volts)
High voltage (more than 36000 volts)
- Insulating medium – air, gas, oil, vacuum
- Construction type – indoor, outdoor, industrial, metal-enclosed, metal-clad…
- Type of current – AC, DC
- By application – transmission system, distribution
- Operating method – manually, motor or solenoid/stored energy
Components of Switchgear:
It includes two components namely power conducting and control systems. The components of power conducting include fuses, switches, circuit breakers, lightning arrestors which are used for interrupting the flow of electrical power.
Control systems like control panels, transformers like potential, current protective relays & connected circuitry that controls, monitors & protect the components of power conducting.
Features Of Switchgear:
Reliability – switchgear is employed during a power grid to enhance the reliability when a fault occurs in system switchgear must isolate the faulty section from the rest circuit
Absolutely certain discrimination – if fault occurs during a power grid then switchgear must be ready to discriminate between the faulty section and healthy section.
Quick operation – if any fault occurs during a power grid then switchgear must be ready to act quickly in order that no damage is completed to the equipment
Provision for manual control – switchgear must have manual control just in case of any electrical or electronic control fail
Provision for instruments – provisions for the instruments is required this might be within the sort of ammeter, voltmeter.Read more