The power distribution grid is the complex system that brings electricity from the power plants to factories, offices, homes and other places.




This is where it all starts. Electricity is produced in power plants through large power generators.


A generator is a machine composed of wires and magnets that converts mechanical energy to electric energy.


Electricity is produced by the generator as it spins. This may be done by wind mill, water turbine (in hydroelectric plant), gas turbine, steam turbine (in thermal plant) and diesel engines.




From generators to consumers, electricity must travel long distances. To travel efficiently, its voltage is increased to very high levels through step-up power transformer in the transmission substation.


Why do you need high voltages?


Voltage can be likened to a water pressure. In a very long water hose, you will need a very high water pressure in order to push water to the end. Similarly, you need high voltages to push electricity to the other end. If low voltage is used, what used to be 220 volts from the source can be 10 volts on the other end. Or one can use very large wires to maintain the voltage up to the other end, but that won’t be economical.


From the transmission substation, electricity is brought to different towns and cities through high voltage transmission lines. A typical transmission distance is around 300 kilometers. Typical voltages for long distance transmission range from 230kv and 500kv.


High-voltage transmission lines are quite recognizable. They are normally made of huge steel towers like this:




At the end of the high-voltage transmission line in town or city, bulk power or delivery point substation is connected. The power transformer in this substation lowers the voltage to sub transmission level, usually at 115,000volts


When electricity comes closer to where it is used, its voltage is further reduced to distribution level (34,500 volts or less).


Inside the distribution substation are other electrical devices such as breakers and switches which function similarly to a house’s protective electrical system.




From the distribution substation, several distribution lines go out to the streets to carry the electricity to different places where the consumers are located. Majority of the distribution lines are installed “overhead” or on poles and a few are built underground.




Since the voltage at the distribution line is still high (34,500 volts), it must be reduced to a useable level, normally 220 volts, before it reaches the consumer.


The voltage reduction is done through the distribution transformer attached to a pole. This transformer is the drum-shaped equipment installed near the top of the pole. Connected to this transformer are secondary lines that finally bring the electricity to homes, offices, factories and other users.


What an unbelievable story!


It took all of that equipment to get power from the Power Plant to the light in your bedroom.




Community News