about transmission lines

hello guyz
i have a small question about transmission lines. i know this question is not related to electronics but it is general knowledge
why we rise up the voltage in the T.L. when we use it with long distance transmission , i know that the reason is to decrease the losses but i want an explanation

thanx alot

Electrical transmission lines carry power. Power equals the voltage times the current. If the power is high then if the voltage is low then the current must be high and the wires must be huge, heavy and expensive to pass high current without loss. But if the power is high and the voltage is stepped-up then the current is low and inexpensive wires can pass it without much loss.

Adding on what audioguru said, the power dissipation is P=RI^2. So if you use high current to carry the power, you make a ton of loss. If you instead "transfer" all that power into voltage (with P=VI like audioguru mentioned), then you still have the same amount of power, but less current. If you do it this way, you still send the same amount of power but because your current is less you have less loss.

Neat huh? But I'm obviously biased about what I think is neat...like heatsinks! lol.

that`s right i have got it now thanx all and happy new year