Just a question:
Why does demand exceeding supply cause the frequency to drop?
In my mind it should cause the voltage to drop?
If this question is too long to answer on HN, are there any good resources that explain this?
Why does demand exceeding supply cause the frequency to drop?
In my mind it should cause the voltage to drop?
If this question is too long to answer on HN, are there any good resources that explain this?
If the amount of force that's available doesn't increase, the generator slows down. The generators are synchronized to the grid. Of course, as the frequency drops, power plants regulate by applying more force to the generators (e.g. increasing the amount of gas or water fed to a turbine).
So frequency should go up, not down.
As the spin is directly proportional to the frequency
Parent comment: Increasing load makes the frequency go down because ...
Your comment: Decreasing load makes the frequency go up
Your comment is in agreement with everything before, but you said it in a tone of disagreement. Maybe you misread the parent comment?
Grids using multiple generators use "frequency droop," deliberately governing the generators so that as power goes up, frequency goes down. This makes it easier to load-balance between generators connected in parallel.
If one generator were to be "overloaded," its frequency would go down, increasing power output from other generators.
When connecting a new machine, it's frequency is typically slightly higher than the grid; after it is connected it "assumes" some load and its frequency drops to match the grid's frequency.
Generators are just spinning magnets. When load goes up, magnetic resistance goes up, so given the same input mechanical power, the spinning will slow down.
I would imagine this is common practice in power generation in general.
https://business.directenergy.com/blog/2016/may/reactive-pow... https://openei.org/wiki/Definition:Reactive_Power
https://old.reddit.com/r/AskEngineers/comments/1tnbob/why_do...
Same with an electric generator/motor: if you pull power off more than it’s being driven, each push from the driving field is less than enough for the rotational rate, so the rotation is slower, and thus the frequency too.