Explain why the electric company increases the voltage of electricity for long-distance transmission?

Answer 1

Higher voltage means less current so smaller wires and less losses for same power

Answer 2

The wire has a resistance, be it low, but it is there. If the voltage goes a long way, it drops according to Ohm's Law. E = I x R E is Energy in Volts, I is current in Amperes and R is Resistance in Ohms.
The resistance of the wire creates a small amount of heat which is lost making the power down the line lower than at the source. Transformers break the voltage down to the level that we use, usually from about 7200 Volts to 240 Volts. There are several hookups (taps) that allow the transformers to be hooked up to compensate for the power lost at the various points from the source to get the needed voltage. You may have a voltage drop of 100 volts for great distances from the source to the last user on the lines. If needed, there are substations that boost the voltage for another long run from that point.

Answer 3

Consider these facts:
1) Wire has a resistance. Voltage gets lost along a resistance.
2) The amount of voltage lost along a resistance depends on the current flowing through the resistance = wire.
3) The power (Wattage) used by consumers is a function of voltage times current. So the higher the voltage, the lower the current.
4) The lower the current, the lower the loss along the wire [see 2) above].
And therefore they use a higher voltage.

Answer 4

The percent voltage drop across the same transmission line is less for higher voltages and less current. You also lose less power in the line.

Example: 100v at 10amps over a 1ohm line gives a 10volt drop in the line, or 90v delivered to the load. That's a 10 percent Voltage loss and a (I^2R=) 100 watt power loss in the wire.

1000v at 1amp delivers the same power to the load over the 1 ohm line but only drops 1 volt in the line. That's only a .1 percent loss in line voltage at the load and the power loss is less, I^2R= a 1 watt loss.

You can see why as the line gets longer for long distance transmission you have to go to much higher voltages to deliver any kind of voltage to the load and by doing so you lose less power in the line to boot.

Answer 5

Electric supply voltages for long distance transmission has to be raised so that line current will be less and the most economical to be carried by cables Energy loss which is = to I.I R would be least with less line current and cable resistance.
With less current, one may select smaller cables and make the installation, the most economical.

Answer 6

Previous answer is right about thinner wires, but thin wires have higher resistance, so they cause higher ohmic losses.