What's the relationship between power and voltage in transmission?

Power and voltage in transmission are directly related, as power is the product of voltage and current according to Ohm's Law.

In more detail, power (P) in an electrical system is given by the product of the voltage (V) and the current (I). This relationship is expressed by the formula P = V x I, which is known as Ohm's Law. Therefore, if either the voltage or the current increases while the other remains constant, the power will also increase. Conversely, if either the voltage or the current decreases while the other remains constant, the power will decrease.

In the context of power transmission, high voltage is used to transmit power over long distances. This is because, for a given power, a higher voltage results in a lower current (since P = V x I). Lower current is desirable in power transmission because it reduces the power loss due to resistance in the transmission lines. This power loss is given by the formula P = I^2 x R, where R is the resistance. Therefore, the power loss increases with the square of the current. By using high voltage, the current can be kept low, thus minimising power loss.

However, high voltage also poses safety risks and requires more insulation, so transformers are used at both ends of the transmission line to step up the voltage for transmission and then step it down for safe use. This is why you often see large transformer stations near power plants and smaller ones in residential areas.

In summary, power and voltage in transmission are directly related, and understanding this relationship is crucial for efficient and safe power transmission.