I am endlessly fascinated that the grid frequency across an area the size of entire countries/continents gets driven, at the end of the day, mechanically by countless titanic sized spinning machines that slow down when more load is offered, and vice versa.

The shafts are so enormous and heavy that they must be driven by an auxiliary motor when not in use in order to prevent them from permanently sagging.

I assume this sag is something that would only become relevant over a fairly long period of time? Otherwise how were the devices constructed originally, I doubt they were spinning instantly.

They can presumably be fully braced when not in use, but not in the application?

The "European" grid also expands to northern Africa[0]. The Wikipedia map is a little weird, because I remember doing consulting for an energy company at the time the two Danish grids were combined. I suppose it has to do with transmission capacity, but technically Denmark can route power from west to east (the other way is typically less useful as the majority of the power generation is in the west). Western Denmark also has cable running to at least Sweden and so does Germany, so why it's not viewed as one network seem strange.

0) https://en.wikipedia.org/wiki/Synchronous_grid_of_Continenta...

Off-topic;

Why does America use 60Hz? I've never found a satisfactory answer.

> They were disposed to adopt 50 cycles, but American arc light carbons then available commercially did not give good results at that frequency and this was an important feature which led them to go higher

"The origins of 60-Hz as a power frequency" https://ieeexplore.ieee.org/document/628099

Better question is why did Germans pick 50 Hz, I'm not aware of any comparable benefits of having lower frequency

If I read your source correctly, there is no real advantage of 60 Hertz or 50 Hertz, and the decision was usually due to circumstantial reasons, like supporting some existing arc-lights or difficulties with induction motors. Induction motors are also the reason why some railways chose to use 16⅔ Hertz, still in use to this day.

In the end, there is no real difference between 50 or 60 Hz, there is no clear advantage to either, especially with modern components. But you do have to choose as the whole network is synchronous.

How is better working lighting not a real advantage?

It would be, but that advantage was with very specific lamps that are now obsolete for more than 100 years.

50 Hz is a lot easier to math (50 Hz = 0.02/s, 60 Hz = 0.0166666). Don't know if that's why, but it very easily could be.

60 is the easier one, in that you can divide it by 3/4/6/12 and have an integer frequency. Probably the reason why a lot of Babylonian math used base 60, which is where our time and angle measurements come from.

60 is easier to factor, but that's kind of irrelevant when most AC formulas use frequency as a multiplicator. 0.02 is easier to multiply than 0.016667 (though at the end of the day, it doesnt really matter, because pi is used in most of the equations, so it ends up irrational anyway)

> 60 is easier to factor, but that's kind of irrelevant when most AC formulas use frequency as a multiplicator.

Is the fact there are 360˚ (2π radians) in a circle, and 60 goes into that cleanly, of any use?

No really, because functions like sin(), cos() and tan() are defined numerically for "expecting Pi as input" rather than 360 degrees of angle.

Pi (and e) are not only irrational numbers (not fractions) but also transcendental numbers (non-algebraic numbers meaning not roots of polynomials with rational coefficients).

So, even messier for dealing with than, say, square root of two (irrational and algebraic) or square root of minus one (algebraic).

Whoever chose it must have been aware of the use of 60 in time measurement and its practicality: 60 min/hr, 60 sec/min, 60 cycles/sec.

Time traveling Babylonians are proud to have 60Hz electricity.

A better question is why does Japan use Both 60 Hz and 50 Hz in different areas? And that’s really just a legacy from early decisions at different companies when the grid was first introduced, and there’s never been a sufficiently compelling reason for either to swap.

60 Hz is slightly better in terms of flickering, but neither has enough advantages to really be a determining factor on their own.

Isn't this a side effect of one area of Japan building their electrical grid with components from British manufactures while the other used American-made components?

yeah, they had to buy what they can get.

IIRC it was German AEG and General Electric

US did the same, Southern California was 50 Hz at first. It didn't convert until after WWII

There was 25 Hz infrastructure in Ontario until the 1950s

https://www.lifebynumbers.ca/history/the-rise-and-fall-of-25...

Yep, the government had to go house-by-house, building-by-building replacing all electrically powered devices that could not be adapted. Thankfully it also happened early in the era of electronic devices.

it's substantially easier to run modern electronics off random frequency power than other stuff like an induction motor. A typical power supply is rated for 47 Hz- 63 Hz. But it'll happily run off almost anything higher than 10 hz and lower than 1000 hz.

universal motors in particular do not care at all about frequency

oh wow, 25 Hz was supplied to homes? I know New Orleans still has some pumps that run on some oddball frequency. It's part of the reason why they never work during the storms (when you need them). The "grid" is just a set of colocated generation sets

From the above link:

    Sir Adam Beck #1 ten 25 Hz generating units were converted 
    to 60 Hz or modified as follows:
    
    Units 9 and 10 to 60 Hz in 1956
    Unit 3 to 60 Hz in 1970
    Unit 4 to 60 Hz in 1984
    Unit 5 to 60 Hz in 1985
    Unit 8 to 60 Hz in 1990
    Unit 6 to 60 Hz in 1996
    Unit 7 to 60 Hz in 2009

2009! Talk about legacy support.

* https://en.wikipedia.org/wiki/Sir_Adam_Beck_Hydroelectric_Ge...

* https://www.opg.com/stories/opgs-sir-adam-beck-i-hydro-stati...

These frequencies are often inherited from whoever was the first grid operator, and electricity producer. Same goes for lot of other parameters.

50 and 60Hz were about equal in transmission efficiency but in 1891 Westinghouse engineers decided 60Hz produced less perceptible flickering in light sources.

Things are the way they are because they got that way over time.

Civil infrastructure is legacy systems all the way down. Once a choice is made, it's hard to change. In the city where I am, some of the design decisions date back to the Romans.

Surprised this isn’t already available. Does Estonia only publish 5 minute frequency data?

For other folks who find grid identity as a shared frequency fascinating, this week's Complex Systems podcast won't disappoint.

https://www.complexsystemspodcast.com/episodes/electricity-g...