When 3-phase AC source transferred from long distance Why the power loss is very less When compared to single?

Question

i wanna know the main principles .If it is shown by diagram it would be better.



THANKS IN ADVANCE

Answer 1

It is not the power loss during transmission that favors three phase over single phase. It is principally due to the rotational mechanical to angular phasor electrical energy conversion efficiency of generation, and, marginally the amortization of the return (ground) wire's cost over three, rather than one, hot wires.

Answer 2

I never thought 3 phase could reduce transmissin loss. Your question just made me think. In 3 phase power loss in the return path can be saved. In a balanced 3 phase load the neutral current will be zero. So power loss will be there in only one conductor. Per phase power loss will be half compared to single phase.Also it can be connected in delta where neutral wire is not required at all even if load is not balanced.

For your info I will brief you about the principles of 3 phase. AC current is like a sine wave. In 3 phase these sine waves will peak at different times on each line. So the voltage between any two lines will be above 400v. But each line will show 230 volt with respect to neutral. In transmission you will transmit at high voltage but the ratio will remail same. The saving is three return paths and the power loss in three return paths. This neutral omited during transmission can be recreated by star connecting secondaries of step down transformer at the distribution side.

Answer 3

Dont know if this will answer your question, but if you have the same load for the 3 phase and the single phase, the conductors on the single phase are going to have to carry the same amount of current as in the 3 phase, which would mean you would need a larger conductor. If you used the same conductor then you would have a nice fire and that is where your getting your power loss. FYI, over long distance, it goes for AC to DC.

Answer 4

In 3 phases AC source transferred from long distance the voltage is high and tension in the wires are also very high. So due to corrona and proximity effect the loss is negligible .
But in single phase the capacitive effect is only between the line and the earth. There is no capacitance exist between any other conductors.so the energy consumption is less& the loss is more.

Answer 5

Electric power is transmitted at higher voltages (132, 220, 400 kV) to reduce I^2R loss and to use lower conductor size. DC high voltage transmission at 400kV has also some inherent advantages and gaining popularity.

The power is generated in power house as 3 phase and transmitted to the load centre as 3phase as it is economical to transmit 3phase power. You require 3 wires to transmit 3phase power whereas 2 wires are required to transmit 1phase power.

Loss will be more in 1phase as the I^2R loss in the Neutral is extra in case of 1phase transmission.