Explain why a Direct current system cannot use an efficient stepped up voltage for long distance transmission ??
2007-06-06 17:56:18 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Engineering
Very high voltage direct current is more efficient than AC for long distance transmission. For the same wire resistance, the DC transmission and AC (of the same RMS voltage) experience the same resistive power loss. However, AC experiences additional power loss due to electromagnetic radiation from the wires. This radiative loss increases with voltage. Therefore very high voltage DC is used for long distance power transmission. The higher the voltage, the less current is needed for the same load power, and therefore less resistive power loss in the lines.
The disadvantage of DC transmission is that conversion to lower voltages is less efficient than AC (AC uses transformers, but DC conversion needs active circuits). But for long distances, this is less significant than the power loss in the lines.
2007-06-06 18:15:46 · answer #1 · answered by gp4rts 7 · 0⤊ 0⤋
DC is not alternating or changing direction so it can not used transformer to step up the level of voltage magnitude. Due to the ohmic resistance of the transmission line so you need high voltage with low current to lower the power loss and increase the effeciency of transmission.
2007-06-08 13:06:52 · answer #2 · answered by dongskie mcmelenccx 3 · 0⤊ 0⤋
Hi. DC current is subject to resistive losses that are related to distance transmitted. AC (at high voltage) has less resistive loss.
2007-06-07 01:00:01 · answer #3 · answered by Cirric 7 · 0⤊ 0⤋