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Science-Related Homework Help Physics Topic started by: leemons on May 8, 2013



Title: Why is long-distance transmission of electrical energy economical only if there is a low current/high voltage?
Post by: leemons on May 8, 2013
I don't understand how the high voltage reduces the current required in the transmission lines, which makes the energy lost to resistance low. Can you prove this mathematically, or in layman's terms? Thanks.


Title: Why is long-distance transmission of electrical energy economical only if there is a low current/high voltage?
Post by: irina on May 8, 2013
The cable resistance is a constant, and power lost in a resistor is I^2 * R. So if you reduce the current I low, you reduce the I^2*R loss.

The total amount of useful power you are generating is I*V. If it adds up to 1000 Amps at the wall socket at 120 V, then the same power is only 10 Amps at 12000 V. So by stepping up the voltage you deliver it at, you can reduce your current, reducing the wasted power, while delivering lots of useful power.


Title: Why is long-distance transmission of electrical energy economical only if there is a low current/high voltage?
Post by: o2226500 on May 8, 2013
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