[nikisweeting]

There is a line that’s incorrect in the article:

> AC won, mainly because of its higher efficiency when transported over long distances.

AC is not actually more efficient at long distance transmission, it’s less efficient due to the skin effect. AC is just easier to convert.

[axiolite]

It's not "incorrect". They literally explain the reason why they say it is so in the very next sentence. Only taken out of context does it appear incorrect.

[nikisweeting]

The sentences after explain why higher voltage is more efficient than lower, they don’t say anything about AC vs DC efficiency. The Skin Effect is also not mentioned anywhere in the article.

[dehrmann]

Yeah, this is a huge myth I hear repeated all the time. AC won because losses are lower at higher voltage and yes, AC transformers (which are necessitated by high voltages) are easy to make.

[bombcar]

Yeah I seem to recall that many extremely high voltage long distance lines are actually DC

[Robotbeat]

Indeed. This is because you get phase differences (due to finite speed of signal in wire, even though it's near c) over those distances. Converting to DC and then back to AC at the destination avoids any concern about phase mismatch.

[lbriner]

It isn't just that. afaik, a much larger issue is related to capacitive and inductive losses of AC. Even on the railways, an adjacent 25KV overhead line can induce a few hundred volts into the adjacent "dead" line, which is why they must be earthed before you can work on them.

[fuoqi]

There are two main reasons for using DC for long distance power lines:

1) The line connects two synchronized grids. It's much easier to convert electricity to DC and back to AC on receiving end, than to synchronize grids or to implement something similar with AC.

2) The line runs under sea water for a significant distance. Due to the conductivity losses DC is more efficient in such contexts that AC.