What is Switchgear and Why Do We Need It?
What is Switchgear and Why Do We Need It? https://www.theelectricalguy.in/wp-content/uploads/2024/07/what-is-switchgear-1024x576.jpg 1024 576 Gaurav J https://secure.gravatar.com/avatar/87a2d2e0182faacb2e003da0504ad293?s=96&d=mm&r=gWhat is a Switchgear? – If your answer for this question is “All the switching devices are called switchgear”, then you are not completely right. In this blog, we’ll understand what switchgear is and why we need them. In the end, we’ll also see the proper definition of switchgear given by the IEC standard.
Understanding Electrical Energy Management Systems: The Role of Switchgear
The ultimate aim of electricity is to get consumed. Since we generate electricity far from its end user, we need to transmit and distribute the power. To make this happen, we need an electrical energy management system. This system ensures that electricity is supplied to all consumers at all times, at the rated voltage, rated frequency, and in the specified waveform. All of this should occur at the lowest cost possible.
Managing Electrical Energy
In this process, we often need to raise or lower the voltage. Integration of electricity from different sources like wind and solar, along with conventional sources and HVDC transmission, is necessary. The distribution system itself is complex, with inputs coming from multiple substations and supply going to multiple feeders and different distributors . If you’re interested in understanding terms like feeder, distributor, and service mains Click Here.
Complexity of the System
The system is complex with multiple inputs and outputs, and changing voltage levels multiple times. To manage such a complex system, we need switching devices capable of switching the supply at every level, protective devices to safeguard the system during abnormal situations, and measuring devices at every level.
Example 1 :
Power is generated in a power station at 11kV. To transmit this power over a long distance, we need to increase the voltage level to minimize losses. Here, a transformer is needed along with switching, protection, and measuring devices, marking this as primary transmission (see the figure below). Voltage is then stepped down to integrate with the sub-transmission level, where inputs may come from multiple substations, necessitating switching, protection, and measuring devices. This need continues down to primary and secondary distribution where voltage is further stepped down.
Example 2 : Switchgear in Everyday Life
Even in our homes, we rely on switchgear:
- Switches: Turn on/off the supply.
- MCBs (Miniature Circuit Breakers): Protect against short circuits.
- Meters: Measure electricity consumption.
So the point is, at every stage, we need switching, protection, and measuring devices. Switchgear is a general term covering a wide range of equipment concerned with switching and protection.
What is Switchgear ?
Let’s understand switchgear with a simple example. Imagine there is fault in the system. This fault must be cleared by the circuit breaker. But, circuit breaker is not capable of sensing this abnormal condition (fault condition) on its own. So, in order to sense the faulty condition we need a device called “Relay”. Relay senses the abnormal condition and gives signal to circuit breaker to trip or open. But, the problem with the relay is that they are small and not cable to accept the high current or voltage that is there is the system. They operate on much lower values of current and voltage. And hence, to fulfil this condition we need to have an instrument transformer (voltage/current transformer) which will lower the value of current/voltage and offers the input to relay (refer below figure for more clarity).
So, to clear the fault, on a border level, we need circuit breaker, a relay and an instrument transformer. And everything put together we call it as “Switchgear”. Everything that is involved in a fault clearing process can be referred as “Switchgear”. Switchgear is a comprehensive term.
What is the definition of Switchgear ?
The International Electrotechnical Commission (IEC) provides a comprehensive definition . According to the IEC standard :
“Switchgear is a general term covering switching devices and their combination with associated control, measuring, protective and regulative equipment, also assemblies of such devices and equipment with associated interconnections, accessories, enclosures, and supporting structures.”
The definition clearly states that switchgear includes switching devices along with control, measuring, and protective devices plus their assemblies, enclosures, and support structures. Remember, switchgear is not only switching devices.
Importance of Switchgear
Switchgear improves the efficiency and reliability of the system. It quickly detects and clears faults, saving the system. It also helps in distinguishing the faulty area while continuing power supply to other areas. For power flow management, switchgear plays a vital role in the power system.
Type of Switchgear
Switchgear majorly can be classified into:
- Low Voltage Switchgear (up to 1000 v)
- Medium Voltage Switchgear (1kV up to 52kV)
- High & Extra High Voltage Switchgear (Above 52kV)
In the next post, we’ll explore these types in detail. Stay tuned!
Conclusion
Switchgear is a comprehensive term. And it is more than just switching devices; it includes a range of equipment necessary for the safe and efficient operation of electrical systems. Switchgear are essential part of a power system and hence understanding the basics of it is very crucial.
You can also watch my video on switchgear for more detail.
