Switchgear

Although this definition may be extended to include devices to regulate and meter a power system, circuit breakers, and similar technology.
In the event of an electrical surge, an effective switchgear will trigger, automatically interrupting the flow of power and protecting the electrical systems from damage. Switchgears are also used for de-energizing equipment for safe testing, maintenance, and fault clearing.
Switchgear Examples
As stated, the term switchgear may refer to a number of different systems and components. Switchgear examples include the following:
• Switches
• Fuses
• Isolators
• Relays
• Circuit Breakers
• Lightning Arresters

Switchgear types
There are three different classes of switchgear systems: low-voltage, medium-voltage, and high-voltage. To determine which switchgear system is right for you match the design voltage of any system to the voltage rating of the switchgear.

High-Voltage Switchgears
High-voltage switchgears are those that control 75KV of power or more. Because these breakers are designed for high-voltage use, they often include improved safety features.

Medium-Voltage Switchgear
Medium-voltage switchgear are used in systems from 1KV up to 75KV. This switchgear is often found in systems involving motors, feeder circuits, generators, and transmission and distribution lines.

Low-Voltage Switchgear
Low-voltage switchgear are designed to regulate systems of up to 1KV. These are commonly found on the low-voltage sides of power-distribution transformers and are used across a variety of industries.

Isolating Media
In addition to the different voltage levels, switchgear may also be defined by the isolating media each uses to protect energized devices from electrical faults. The switchgear enclosure may make use of various insulators with different dielectric properties or other characteristics.

Air
Although the least expensive insulation option (and thus the most commonly used), the air has a low dielectric strength, making it a relatively poor insulator. As a result, air-insulated devices are typically larger than devices insulated by other media.

Fluid
Fluid offers better insulation when compared to air, and is similarly inexpensive. Fluid also provides the added advantage of cooling for overheated systems.

Gas
Pressurized gas also offers increased dielectric strength compared to standard air insulation. Although Sulfur Hexafluoride is a common insulating gas for switchgear systems, other gases may be used in its place.

Oil
Oil has a high dielectric strength, and may also provide increased cooling benefits.

Solid
Although less common and more expensive than some other options, solid, non-conductive materials can provide exceptional dielectric strength, as well as resistance to chemical and thermal deterioration.

Switchgear vs. Switchboard
The term “switchboard” is sometimes used synonymously with “switchgear.” However, these two devices have different primary functions.
Where a switchgear exists to connect and isolate load equipment to and from power sources, switchboards are used to direct the flow of electricity in a power distribution system.