Electrical power is transmitted over long distances at very high voltage because
- A. high voltage travels faster
- B. the current is then small, so the I squared R heating loss in the cables is small
- C. high voltage cables are cheaper
- D. consumers need high voltage
Explanation
For a given power, raising the voltage lowers the current in proportion, and since the loss goes as the square of the current, a tenfold rise in voltage cuts the wasted heat a hundredfold. Transformers then step the voltage back down for safe use at the consumer end. This is the main practical reason the grid runs on alternating current.