Transmission of electricity

• At Hwange, Kariba, Munyati and other places AC power is generated
• This is because the most efficient power generators produce AC power
• In addition to that AC power can be stepped up and down using transformers
• Direct Current cannot be stepped up or down using transformers
• Electrical energy is generated at 4 000 V (4kV)
• It is stepped up to 132 000 kV
• It is then fed into the network of power lines which cover the entire country
• This is network is also known as the National Grid
• It is operated by ZETDC (which is part of ZESA)
• When it reaches its destination it is stepped down to 240V
• At substations readying it for domestic use
• Some industries and mines have their own substations
• These substations also step down the supply from the overhead national grid cables to various voltages
• These voltages vary from industry to industry depending with their intended useage
• Electricity is transmitted at higher voltages
• As this allows thinner wires to be used
• Thinner wires are cheaper compared to the very thick wires that would be otherwise required
• The national grid allows electricity to be generated at advantageous locations
• For example at Hwange where there is plenty of coal
• At Kariba where there is plenty of water in the Kariba Dam
• Or by using molasses in the low-veld

To access more topics go to the Combined Science Notes page.