The National Grid - Ireland's Transmission System
The national grid system supplies electricity to customers - Leaving Cert Physics - Question 11 - 2013
Question 11
The National Grid - Ireland's Transmission System
The national grid system supplies electricity to customers. The grid consists of a network of high voltage transmi... show full transcript
Worked Solution & Example Answer:The National Grid - Ireland's Transmission System
The national grid system supplies electricity to customers - Leaving Cert Physics - Question 11 - 2013
Step 1
What are the key components of the national grid?
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Answer
The key components of the national grid include:
A network of high voltage power transmission stations
Power lines
Cables delivering power
Sub-stations that convert high voltage electricity to lower voltage for distribution.
Step 2
Why are high voltages used to transmit power over the national grid?
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Answer
High voltages are used to minimize power losses due to resistance in the transmission lines. The formula for power loss in the lines can be expressed as:
Ploss=I2R
where I is the current and R is the resistance. Higher voltage results in lower current for the same power transfer, thereby reducing losses.
Step 3
Why is the power supplied to domestic customers at lower voltages?
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The power supplied to domestic customers is at lower voltages for safety reasons and to ensure compatibility with household appliances, which typically operate at a lower voltage range.
Step 4
Name two renewable and two non-renewable energy sources used to generate electricity.
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Answer
Two renewable energy sources are:
Wind
Solar
Two non-renewable sources are:
Coal
Natural gas.
Step 5
The national grid uses alternating current (a.c.) rather than direct current (d.c.). What is the difference between them?
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Answer
The difference between alternating current (a.c.) and direct current (d.c.) is as follows:
A.C. varies in direction and magnitude, changing periodically, whereas D.C. flows in one direction only at a constant voltage.
Step 6
Name the device used to convert high voltages to lower voltages?
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Answer
The device used to convert high voltages to lower voltages is called a transformer.
Step 7
Give the principle function of the device named in part (f).
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The principle function of a transformer is to change the voltage level between circuits, either stepping it up or stepping it down according to the requirements of transmission and distribution.
Step 8
Name one unit of electrical energy that is used in the delivery of electricity to homes and businesses.
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One unit of electrical energy commonly used in this context is the kilowatt-hour (kWh).
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