GCSE PHYSICS - MAGNETISM AND ELECTROMAG - LESSON 20 - transformer part 2
How is Electricity Transported from Power Stations to Homes?
Overview of Electricity Transportation Process
- The lesson focuses on the transportation of electricity from a power station, such as a fossil fuel or nuclear power station, to homes.
- Fossil fuel power stations convert chemical energy (from coal, oil, or natural gas) into heat in their furnaces; nuclear stations convert nuclear energy into heat in reactors.
Generation of Electrical Energy
- Heat generated is used to produce steam, which drives either a gas turbine or steam turbine connected to an alternator (AC generator).
- The alternator converts mechanical movement into electrical energy and typically operates at 50 cycles per second (50 Hertz).
Voltage Production and Transformation
- A typical alternator produces around 25,000 volts; however, this voltage is too low for efficient long-distance transmission.
- To transport electricity efficiently across distances, the voltage must be increased using a step-up transformer that raises it from 25,000 volts to approximately 400,000 volts.
Functionality of Step-Up Transformers
- Step-up transformers consist of primary and secondary coils linked by a soft iron core that conducts magnetic fields.
- These transformers are nearly 100% efficient in transferring electrical energy from the primary coil (connected to the AC generator) to the secondary coil (connected to transmission lines).
Importance of High Voltage Transmission
- Maintaining high voltage during transmission reduces energy losses; lower current results in less energy loss over distance.
- For example, if input voltage is 25,000 volts with an output voltage of 400,000 volts and an initial current of 800 amps, the output current will decrease significantly.
Step Down Transformers for Distribution
- Once electricity reaches urban areas or cities, it needs to be stepped down using series of step-down transformers.