How does the power grid work?

The power grid is an electrical transmission line network to transfer power from the power station to customer. The power-grid consists of an infinite number of power stations connected with the same frequency, phase sequence and standard voltage levels (like 33kV,66kV,120kV,400kV so forth) and transmits power to a long distance either through an overhead or underground power cable system. Normally the power grids are of a high tension voltage level to avoid electrical losses and to reduce economic impacts.  Billions of far flung customers are benefits from this power-grid via distribution sub-stations with an outlet serviceable power supply lines. 

Transmission lines are necessary to carry high-voltage electricity over long distances and connect electricity generators with electricity consumers. Transmission lines are either overhead power lines or underground power cables.