Switchgear refers to a combination of electrical switching devices whose primary functions include switching, controlling, metering, regulating, isolating, and protecting electrical circuits and equipment. Some of the devices that are encompassed within the switchgear are circuit breakers, contractors, fuses, offload isolators, switch fuse units, and switches.
Apart from their different components, switchgears also have various classifications. Generally, switchgears are classified based on their voltage levels. There are three main categories of switchgear: low voltage, medium voltage, and high voltage. Each of these classifications has their own corresponding functions.
Read on to learn more about how the various classifications of switchgear differ from one another in terms of their nature and uses.
1. Low Voltage Switchgear
Low voltage switchgears are typically used for the voltage range of 1000V and 1500V DC current. Hence, they collectively refer to low voltage circuit breakers, earth leakage circuit breakers, miniature circuit breakers, molded case circuit breakers, offload electrical isolators, HRC fuses, and switches. All these accessories are necessary to protect the low voltage system.
A low voltage switchgear generally has three main parts: incomer, sub-incomer, and feeder. Its primary functions are to protect the elements of the circuit against thermal and mechanical stress and to disconnect the circuit apparatus from the rest of the energised system to enable the isolated part to be worked on while ensuring safety. To ensure the efficiency and safety of a low voltage switchgear, all its components should be checked annually.
2. Medium Voltage Switchgear
For the voltage range of 3.3kV to 33kV, medium voltage switchgears are generally the ones utilised. This kind of switchgear is essentially used for the supply of electrical energy that connects with multiple networks. It is made up of substation devices like air, vacuum, as well as minimum and heavy oil circuit breakers. It comes in several types including metal-enclosed indoor and outdoor types, as well as outdoor type without metal shield.
The main function of a medium voltage switchgear is to disrupt the current flow of power when any incorrect conditions occur. This includes conducting switching activities like on and off, providing interruption during short-circuit conditions, switching capacitive and inductive currents, and several other special functionalities. Like low voltage switchgears, the components of this type of switchgear should also be checked every year to avoid any kinds of switchgear failure.
3. High Voltage Switchgear
High voltage switchgears are usually chosen for the voltage range beyond 36kV. Since the voltage level here is greater, the arcing that is generated during switching operation is also high. Therefore, extra care and consideration is necessary while constructing these high voltage switchgear devices. The essential component of this type of switchgear is the high voltage circuit breaker.
Most of the time, the high voltage circuit breaker needs to remain ON and may be operated after a long period of time. Hence, it needs to have special features to facilitate a safe and reliable operation. A high voltage switchgear mainly functions to isolate electrical circuits from the primary power source in order to help in the safe clearance of electrical faults and general maintenance. This type of switchgear also has devices that aid in the distribution and control of electrical current.
Knowing the different classifications of switchgears is important to help you ensure that you choose the right kind of switchgear for your generator or other electrical equipment. Switchgear is a fundamental component of these equipment, as it plays the very essential role of ensuring that electricity distribution is done in a safe and secure manner.
To make sure that you select the right type of switchgear, it is highly recommended to seek the advice and assistance of a specialist. There are a few reputable electrical and engineering companies in Singapore that you can trust with your switchgear. They provide cost-effective switchgear testing and installation as well as other vital services like generator overhauling, transformer maintenance, and electric motor rewinds.