Скачать или смотреть How Power Plants Work | How do Substations Work | Course Materials

What is a Substation?

How does an electrical substation work? Why is it known as a “substation?” Normally stations are where we catch trains or buses. By the same analogy we can explain what a substation does. Electricity has to be transmitted over large distances as the place where the power is being generated and the place where it is consumed can be far apart. The electricity is transmitted at very high voltages and low currents to reduce the heat, eddy currents, and other transmission losses. The substations are where the voltages are increased to high values by using step-up transformers, and after the transmission, they are again stepped down for distribution. In addition to changing the voltages the substations have, a variety of protective devices like circuit breakers and fuses are present to protect the distribution networks. These are designed in such a way that various distribution circuits can be isolated for repairs and load shedding. Substations are normally outdoors and are enclosed by a wire fence. However, in residential or high-density areas, the substation may be indoors and housed inside a building to restrict the humming noise of the huge transformers.

Operation of a Substation
Electricity is generated in a thermal power plant, hydroelectric power plant, nuclear power plant, etc. This electricity is then supplied to a transmission substation near the generating plant. In the transmission substation, the voltage is increased substantially using step-up transformers. The voltage is increased to reduce the transmission losses over long distances. This electricity then is supplied to a power substation where it is stepped down using step-down transformers and then supplied to a distribution grid. In the distribution grid, there are additional transformers and voltage is further reduced for distributing further down the grid. From here the electricity is supplied to step down transformers near residential quarters that step down the voltage to 110/220 Volts as per each country’s requirement.