Types of Switchgear

Electrical switchgear is a centralized collection of circuit breakers, fuses, and switches (circuit protection devices) that act to protect, control, and isolate electrical equipment. The circuit protection devices are installed in a metal structure. A collection of one or more of these structures is called a switchgear family or assembly.

Switchgear is commonly found in electric utility transmission and distribution systems as well as in medium to large commercial or industrial facilities. Standards for electrical switchgear are defined by the IEEE in North America and the IEC in Europe and the rest of the world.

How does a switchgear work?

Electrical switchgear is a group of circuit protection devices (circuit breakers, fuses, or switches) installed in a common metal enclosure. Circuit protection devices distribute power to various parts of the facility and to the electrical loads within those parts. They also provide protection for individuals and equipment throughout the facility by limiting the current flowing through the system to safe levels.

High Voltage Switchgear     

Switchgear has two types of components.

Conductive components: conduct or interrupt the power flow; e.g. switches, circuit breakers, fuses, disconnectors, relays, lightning arresters, etc.

Control systems: These monitor, control and protect conductive components; for example control panels, current transformers, voltage transformers, associated circuits, etc.

Although the circuit breaker is the main component, it is the combination of the device's internal switching enclosure which allows high voltage currents to be interrupted.

The switchgear is connected directly to the power supply system and can be classified according to the voltage level as

Low voltage switchgear (LV).

Medium voltage switchgear (MV).

High voltage switches (HV).

Switchgear for lower voltages can be enclosed in the building, but higher voltages (approx. over 66 kV) usually require the switchgear to be mounted externally and insulated by air.

Types of switchgear

There are two main types of switchgear: outdoor and indoor. For voltages above 66 kV, output switchgear is used. This is because, for higher voltages, construction work will unnecessarily increase installation costs due to the large spacing between conductors and the large size of the insulators.

Low Voltage Fixed-mounted Switchgear     

Below 66kv there is no difficulty in providing construction work for switchgear at a reasonable cost. The indoor type switchgear is metal-clad and compact. Due to the compactness, the safety distance for operation is also reduced and therefore the required area is reduced.

The switchgear can be a simple open-air disconnector or can be insulated with other substances such as oil, pressurized sulfur hexafluoride gas, or in a vacuum.

In the event of a fault in the power system, high currents flow through the equipment, thereby damaging it and interrupting service. For this reason, automatic protection devices or switchgear are required to protect lines, generators, transformers, and other electrical equipment from damage.

Automatic protection switchgear consists mainly of relays and circuit breakers. When a fault occurs in any part of the system, the relay in that part will start to operate and close the tripping circuit of the circuit breaker, thus disconnecting the faulty part. The normally operating part will continue to supply power as normal, so no equipment will be damaged and the supply will not be completely interrupted. If you want to know more information about the best quality low voltage switchgear wholesale, welcome to contact us.