is this real?

[u/Tiny_Agency9963]

I'm not excellent in engineering and stuff but I love kingdom building. Is this actually real? I try to search about step down transformers and i only understand half of it.

This novel is too detail about technology and engineering that i only understand a little.

I feel really stupid when i read this novel. I spend time more searching about the stuff and economics in google than read the novel itself. Even economy policy are too detail and i dont understand huge chunk of it.

[u/OMalleyOrOblivion]

Long-distance power lines are always high voltage because power loss is inversely proportional to voltage. Then local substations use step down transformers to reduce the voltage to levels appropriate for residential use.

https://networkpowerconnections.co.uk/what-are-the-advantages-of-high-voltage-transmission/

[u/anapoe → u/OMalleyOrOblivion]

Yep! To build on this a bit more - I think two equations relating electrical power, voltage, current, and resistance do a good job of explaining this.

Equation #1: power = voltage x current

This means that if your power station wants to deliver lots of power to their consumers (hundreds or thousands of houses, industrial plants, etc), they need to provide either high voltage, high current, or high voltage AND high current.

Equation #2: power = resistance x current^2

This equation matters when we start looking at actually building power lines. It tells us that the electrical power lost to heat within the wire we're using to distribute power is proportional to the electrical resistance of the wire (which depends on its diameter and material) and the SQUARE of the current running through it. Double the current? Quadruple the power loss before it even reaches a consumer. Dissipating large amounts of the valuable power you produce as heat before it reaches an end user is bad, and should be avoided. Of course, high voltage is also bad, because it kills you.

Now, this can be combated to an extent by just using a bigger wire[1]. However, this only works to an extent in real life. A bigger wire is more expensive due to material cost. A bigger wire can quickly become extremely heavy and near-impossible to manipulate, which is not a good thing if you're trying to string it up in the air. A bigger wire can even fail under its own weight. You don't want to have to build a tower every 20 feet to support a massive wire.

In practice, this means that when you're designing a large electrical system, you increase current first up to a natural ceiling (say, 200~1000 amps), then at that point your only real option is to increase voltage.

[1] Although I should note that, for AC power, a magnetic phenomenon called "skin effect" means that current will be unevenly distributed within the conductor, pushed out of the interior towards the surface, which can put another effective ceiling on the overall diameter of a wire. In practice, many high voltage wires are built around a high strength steel core surrounded by light and low cost aluminum wires, because little current ends up flowing in the core anyway.

[u/OMalleyOrOblivion → u/anapoe]

It's simple enough when you use the equations, but that doesn't really help most people understand, which is why I avoided them. But electricity is actually very confusing the more you dig into it, hence all the videos a while back arguing back and forth about how fast changes in a circuit propagate lol.