SESK: Stuff Everyone Should Know · sesk.info/eng-high-voltage-transmission
Why do power companies send electricity across the country at very high voltage?
Higher voltage means less current for the same power, so far less is lost heating the wires.
- Less current, so less heat lost in the lines ✔
- High voltage travels faster than low voltage
- Higher voltage carries more electrons per second
Why: Power equals voltage times current. Raise the voltage and the same power needs less current, and line losses grow with current squared, so they shrink a lot.
Huh, didn't know that: Line loss is I squared R, so cutting the current in half cuts the heating loss to one quarter.
Why did the power line refuse to work at low voltage? Too much current stress.
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References
Answer: Less current, so less heat lost in the lines. Power equals voltage times current. Raise the voltage and the same power needs less current, and line losses grow with current squared, so they shrink a lot.
- OpenStax College Physics 2e, 23.7 Transformers openstax.org/books/college-physics-2e/pages/23-7-transformers
less current is required for a given amount of power, and this means less line loss.
Checked 2026-10-10.
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