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dsauerbrun | 2 years ago

I'm not an electrical engineer but it sounds implausible for power to be transferred that far without losing a bunch of it in the process, unless you have massive cables.

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mschuster91|2 years ago

The cables don't need to be massive, but the voltage has to be because the power loss is related to the current flowing - so the Chinese just raised the voltage to 1 million volts instead of the usual 220/380 kV, and used DC instead of AC to get rid of reactive power and skin effect issues. Their longest line transfers 12 gigawatts of power over almost 3.300km distance - that's not that much that remains to cover the distance from the US East to West coast!

[1] https://en.wikipedia.org/wiki/Ultra-high-voltage_electricity...

sophacles|2 years ago

The large long distance AC transmission lines are 765KV. They step that down various substations as lines branch off to feed smaller and smaller areas until you get to the distribution network.

If you draw the map of lines with proportional thickness for various voltage levels it looks vaguely fractal, like an old tree.

jeffbee|2 years ago

HVDC loses 3% in 1000 km, depending on the value of "HV".

bb88|2 years ago

Maybe take some EE courses then? They're not that hard...

From EE101: P=V * I. But power transmission losses are I^2 * R.

So one way to transmit large amounts of power with low losses is to, well, turn the voltage up and use a lower current.

And with lower current, you can use smaller cables.

And in fact, that's what we do.

That's why your power lines to your house are thousands of volts and the transformer hanging on the pole will convert it into 220V (but with higher current to run your hair dryer, say).

SECProto|2 years ago

> I'm not an electrical engineer but it sounds implausible for power to be transferred that far without losing a bunch of it in the process, unless you have massive cables.

Read up about Hydro Quebec. They generate gigawatts in Northern Quebec and export large amounts to New England. HVDC is pretty efficient.

https://en.wikipedia.org/wiki/Hydro-Qu%C3%A9bec's_electricit...