An Overview of Electricity from the power plant
- Slides: 6
An Overview of Electricity: from the power plant to your home Adapted from www. howstuffworks. com
The Power Plant • Remember, energy is merely changing states. • Depending on the type of power plant (hydroelectric, coal, nuclear), the energy is converted from one form (ex. coal) into another (electricity) through various steps – Think of 2 laws of thermodynamics here…how do they apply? • In almost all cases, the power plant consists of a spinning electrical generator. – In most cases, a steam turbine spins the generator. – The steam might be created by burning coal, oil or natural gas or come from a nuclear reactor
Power Grid • The energy (electricity) travels from the power plant to various locations via the power grid. • Depending on where you live, power grid distribution lines can be above or under ground.
Transmission Substation • After the power plant the AC current of electricity leaves the generator and enters a transmission substation at the power plant. • This substation uses large transformers to convert the generator's voltage (which is at the thousands of volts level) up to extremely high voltages for long-distance transmission on the transmission grid. • Typical voltages for long distance transmission are in the range of 155, 000 to 765, 000 volts in order to reduce line losses. A typical maximum transmission distance is about 300 miles (483 km). substation High voltage transmission
The Distribution Grid • For power to be useful in a building, it comes off the transmission grid and is “steppeddown” to the distribution grid (in several phases) at a power substation. – “stepping-down” power reduces voltages via switches, splitters and circuit breakers The transmission lines entering the substation and passing through the switch tower The switch tower & main transformer
At your home • Depending on the neighborhood, there is a transformer outside every house or every couple houses. • The transformer reduces the 7, 200 volts down to the 240 volts that make up normal household electrical service. The transformer is the white cylinder