National Grid Flashcards
Why is electrical energy so useful?
it can easily be transferred into other types of energy.
What does the amount of electrical energy transferred by a device depend on?
how long the appliance is switched on and it’s power.
Define the power of an electrical device.
how quickly it transfers energy.
Define the kilowatt-hour (kWh)
the amount of energy transferred when one kW is left on for one hour.
What is the National Grid?
Cables, pylons and transformers.
What is the purpose of transformers in the National Grid?
Step-up transformers increase and step-down transformers decrease the voltage of mains electricity.
Why do we use step up voltage in the national grid?
High voltage in power lines reduces current. Low current reduces energy losses in the cables.
What is the advantages and disadvantages of underground power cables?
Advantages - not damaged by storms and are not unsightly; Disadvantages - expensive and take long time to repair.
