The delivery of electricity from a power plant to your home is a sophisticated, four-step process.

Generation

Electricity is produced at power generating stations or power plants.

These plants use various energy sources, such as coal (thermal), water (hydroelectric), nuclear fission, wind, or solar energy, to turn turbines connected to a generator.

Step-Up Transmission

The generated electricity is sent to a step-up transformer at a substation located near the power plant.
This transformer dramatically increases the voltage to very high levels (e.g., 400,000 or 765,000 volts).
Purpose: Transmitting electricity at high voltage reduces the electric current, which significantly minimizes power loss (Ploss=I2R) as the electricity travels over long distances through transmission lines.
This high-voltage power is then fed into the national grid, which includes the Inter State Transmission System (ISTS).

Step-Down Distribution

The high-voltage electricity travels across the country to a power substation near a city or town.
Here, a step-down transformer reduces the voltage to a lower, safer level for local distribution.
This power is then sent through smaller distribution lines to a neighborhood distribution transformer (often seen mounted on poles or as green metal boxes on the ground). This transformer further steps down the voltage to the standard level used by households (e.g., 240V in India).

End-User Supply

Finally, the low-voltage electricity is delivered from the distribution transformer to individual homes, offices, and factories through service lines, powering all our appliances.