What is a Switchgear : Working, Types and Its Functions

Electricity in daily life to mankind is the most important blessings to mankind but, once it comes to electricity supply, it needs to be done securely. Thus, to maintain the security level of electrical distribution, it is very hard to employ safety devices. There are different types of devices that help in protecting electrical devices as well as its connections in different areas like industrial, residential, etc. To overcome this, a switchgear device is used because of its different features and functions. This device is used to assist in the carriage & distribution of load while maintaining the electrical connectors. It helps to identify the faults and failure connections so that it can reduce the damage.

What is Switchgear?

Definition: A device that is used to switch, control and protect the circuits as well as devices. This is anxious about switching as well as interrupting currents under different operating conditions like normal or abnormal. In an electric power system, it is an arrangement of electrical disconnect switches, circuit breakers, fuses which are used to protect, control & separate electrical device.  The switchgear diagram is shown below.

It is connected directly to the supply system by placing in the low & high voltage planes of the power transformer. This device de-energizes for clearing the fault, testing & maintaining. These devices play an essential role in the power system to protect the equipment from the heavy current. Otherwise, the device may get damaged & the service gets interrupted. So these devices are essential to protect the equipment from the damage like a transformer, generators, lines, etc.

Features of Switchgear

The main features of this include the following.

• Manual control provision
• Fast operation
• Completely certain discrimination
• Entire Reliability

Working

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 circuit occurs within the power system, then a huge current will flow through the devices. So that the equipment can be damaged & the interruption will occur to the operators. To overcome this problem, it is used to detect the fault in the power system. In this way, this is works to protect the equipment from the damage.

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 electric power.

Control systems like control panels, transformers like potential, current protective relays & connected circuitry that controls, monitors & protect the components of power conducting.

Functions of Switchgear

The main functions of this equipment include the following.

• It protects the equipment from short-circuits & fault currents.
• This device gives isolation to the circuits from power supplies.
• It increases the availability of the system by allowing more than one source to feed a load.
• It can open & close the electrical circuits under the conditions of normal & abnormal.
• In normal conditions, it can operate manually so it ensures the safety of the operator & also proper electrical energy utilization.
• In abnormal conditions, it operates mechanically. Once a fault happens this device detects the fault & detaches the damaged part in the power system. So it protects the power system from damage.

Switchgear Types

There are three types of switch gears namely LV (Low voltage), MV (Medium voltage) and HV (High voltage) Switchgear.

Low Voltage Switchgear (LV)

The power system which deals up to 1KV is called as LV or low voltage switchgear. This kind of equipment 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 called MV (medium voltage switchgear). These are available in different types like without metal enclosure outdoor type, metal-enclosed indoor & outdoor type, etc. This kind of equipment includes substation devices like minimum oil CBs, bulk oil CBs, SF6 gas-insulated, air magnetic, gas-insulated, vacuum, etc.

The disruption medium of this type of switchgear can be vacuum, SF & oil. The main condition of this type of power network is to break off current throughout faulty conditions in this system. This is capable of ON/OFF operation, interruption of short circuit current, capacitive current switching, inductive current switching and used in some special applications.

High Voltage Switchgear (HV)

The power system which deals above 36KV is called HV (high voltage) switchgear. When the level of voltage increases then the arcing will be generated as the switching operation is extremely high. As a result, during the designing of this equipment, special care has to be taken. The main component of this equipment is the High Voltage (HV) circuit breaker.

Therefore HV circuit breaker must include some safe & reliable operation features. The switching operation of the HV circuit is very rare. Usually, these CBs remain at ON state and can be worked after some time. Consequently, these must be reliable to make certain secure operations when required.

FAQs

1). What is the importance of switchgear?

It is used to protect, isolate, and protect electrical equipment from fault currents.

2). What does switchgear do?

It assists in protecting the appliances & electrical machines.

3). What is the difference between a switchboard and switchgear?

Generally, the switchboard is used for less voltage under 600 volts, whereas the switchgear for high voltages up to 350 kV

4). What is the switchgear components?

It includes switches, fuses, lightning arrestors,  Sectionalisers, Auto Reclosures, isolator/disconnect switch, CBS (circuit breakers).

5). What is MV switchgear?

The switchgear is used for medium voltage applications.

Thus, this is all about an overview of switchgear. In modern power systems, this is an essential device to protect the equipment from overload or short circuits. These are classified into two types mainly like HV (high voltage) & LV (low voltage). HV type is used for motors & electrical equipment which operate with above 1000V AC whereas LV type is used to run electrical devices that operate with below 1,000 volts AC. Here is a question for you, what are the applications of switchgear?