What is Electric Power System? A Beginner’s Guide

• January 10, 2025
• Gaurav Joshi

What is Power System?

An electric power system is a comprehensive network involving the generation, transmission, and distribution of electricity. It spans from the generating station to the electrical outlets in our homes, providing power to homes, buildings, industries, and commercial establishments. 

What is Electric Grid?

When a power system supplies power to a significant region, such as a whole state or country, it is referred to as an electric grid.

Structure of Power System

The structure of a power system can be likened to an online shopping system:

1. Placing Order: In online shopping, we place an order.
2. Main Delivery Hub: The order is sent to the main delivery hub.
3. Local Delivery Station: The order is transferred to a local delivery station.
4. Delivery Person: Local warehouse connects the package to the local delivery person 
5. Final Delivery: A delivery person brings the package to your doorstep.

Similarly, a power system works through the following stages:

1. Generation: Electricity is generated.
2. Primary Transmission: The generated electricity is transmitted over long distances.
3. Sub Transmission: The high voltage from the transmission network is connected to the distribution network.
4. Primary Distribution: Voltage is further stepped down and connected to the secondary distribution
5. Secondary distribution: This is where the electricity is delivered to the residential zones or small-scale commercial buildings, etc

Power system is much more complicated than the online ordering system,  but it is a good example to remember the structure of the power system.

Main Components of a Power System

1. Generation:
   • Electricity is generated through various methods like thermal, coal, nuclear, wind, or solar power.
   • Power plants generate electricity at lower voltages (e.g., 11 kV or 25 kV) to use smaller and economically feasible machines.
2. Transmission:
   • The generated voltage is stepped up to high levels (e.g., 245 kV, 420 kV, or 800 kV) to minimize losses during long-distance transmission.
   • High voltage transmission helps reduce losses and is economically advantageous.
3. Sub Transmission:
   • The high voltage is stepped down to connect to the distribution network (e.g., 145 kV, 66 kV, or 33 kV).
   • Some industries take power directly from the sub-transmission phase and have their own substations to step down the voltage for their use.
4. Primary Distribution:
   • The voltage is stepped down to 36kV or 12 KV
   • Customers with high power demand can be fed directly through primary transmissions like data Centre or shopping malls, factories, etc.
5. Secondary Distribution:
   • Distribution substations further step down the voltage to usable levels (e.g. less than 1000 volts).
   • The electricity is then delivered to various consumers, including homes, buildings, and industries.

Example of a Small-Scale Power System

Even small systems, like solar rooftop setups, can be considered power systems. In this case, electricity is generated by solar panels, transmitted to the main MCB (Miniature Circuit Breaker) box, and distributed to different rooms. Similarly, hospitals and some industries have their own power plants and use their generated electricity, forming a complete power system.

Conclusion

A power system is a network encompassing the generation, transmission, sub-transmission, and distribution of electric power. When it supplies power to a large region, it is termed an electric grid. The four main phases of a power system are generation, transmission, sub-transmission, and distribution.

In this complex power system switchgear plays a vital role in keeping the power system safe. Here is the beginner’s guide on what is switchgear – What is Switchgear & Why We Need Them?

Frequently asked questions