[elihu]

He was running ten amps over thin wires; of course that doesn't work. The problem there was that he was transmitting significant power at low voltage and high current. That doesn't say anything about the superiority of AC or DC. AC has historically been the more practical choice because you can trade AC voltage for current easily with a transformer, but there are ways to do that with DC now too. Maybe there's an argument to be made that transformers are cheaper or more reliable than boost converters; I don't know one way or the other.

If wikipedia is to be believed, DC is better in terms of conductor material costs and transmission losses than AC, at least for long distance high-power high-voltage transmission lines.

> A long-distance, point-to-point HVDC transmission scheme generally has lower overall investment cost and lower losses than an equivalent AC transmission scheme. HVDC conversion equipment at the terminal stations is costly, but the total DC transmission-line costs over long distances are lower than for an AC line of the same distance. HVDC requires less conductor per unit distance than an AC line, as there is no need to support three phases and there is no skin effect.

> Depending on voltage level and construction details, HVDC transmission losses are quoted at 3.5% per 1,000 km, about 50% less than AC (6.7%) lines at the same voltage.

https://en.wikipedia.org/wiki/High-voltage_direct_current#Ad...

[dhdc]

> If wikipedia is to be believed, DC is better in terms of conductor material costs and transmission losses than AC, at least for long distance high-power high-voltage transmission lines.

This is correct. DC is a much better choice for long distance transmissions. You don't need to worry about reactive power, skin effect, reactive elements of the line, whether the generators and the grid are synced or not etc. The problem with DC voltage conversion are mostly solved as well.

[distortedsignal]

> The required converter stations are expensive and have limited overload capacity. At smaller transmission distances, the losses in the converter stations may be bigger than in an AC transmission line for the same distance. The cost of the converters may not be offset by reductions in line construction cost and lower line loss.

https://en.wikipedia.org/wiki/High-voltage_direct_current#Di...

Not to mention that circuit breakers are harder in DC.

[dhdc]

> Not to mention that circuit breakers are harder in DC.

[Citation needed]

[elihu]

I can believe this is true. It's easier to make reliable AC switches because whatever arcing you get is self-extinguishing because the voltage passes zero 120 times a second. With DC, if you get an arc it'll just keep going as long as conditions allow. That means if you use a designed-for-AC switch in a DC application with the same voltage, it's likely to destroy itself sooner or later.

(Apparently this is one of the reasons why cars stick with 12V for accessories, because if they used higher voltages the electrical switches would be more expensive and less reliable.)

I don't know how this is normally overcome. In a lot of cases, the solution might just be "use a fuse instead".

[alduin32]

Yes, opening a DC circuit under load can be very surprising. The arcs can just stay on forever, and pose a big fire hazard.

[pfdietz]

A big capacitor?

[distortedsignal]

https://en.wikipedia.org/wiki/High-voltage_direct_current#Hi...