On Saturday (8th of Feb), Baltic countries will disconnect from the Russian power grid and synchronise with the Continental European electricity system. They will operate in "island mode" for 33 hours, and then synchronize with the European grid frequency.
The frequency is a key parameter of the grid. If there is too much load, it goes down, and if there is too much production it goes up. A lot of critical grid infrastructure relies on the frequency being in the 49.5-50.5 Hz range.
I built a tool together with some colleagues to track the grid frequency in real time during this operation over the past few days to follow this process in real time!
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 "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.
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 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
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.
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)
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).
50 and 60Hz were about equal in transmission efficiency but in 1891 Westinghouse engineers decided 60Hz produced less perceptible flickering in light sources.
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?
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
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
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.
Unfortunately for this American, having a different set of standards for mathematical notation tripped a "don't these people know the difference between Hz and kHz?" impulse in my brain.
To illustrate: When an American sees "50,000 Hz" we process it as you would process "50 000 Hz". This misunderstanding could be corrected by using two or four significant figures after the decimal. That's too much to ask though, probably requiring a large number of hours to accommodate someone not even from there.
Your site is fine, it's our brains that are more appropriately adjusted. A little disclaimer link or something would help a number of us understand. A large number of otherwise intelligent and educated Americans don't realize this difference in notation and this would be a great opportunity to educate them.
SI allows either but the document should be consistent. Thousands separators are a half width space.
"The decimal marker shall be either the point on the line or the comma on the line. The decimal marker chosen should be that which is customary in the context concerned."
Gosh I love these electricity grid posts. As someone with almost zero knowledge about the subject, I am fascinated by what I learn. The last one I saw was when Ukraine switched away from Russia days before Russia invaded them.
I don't know that this will happen, but it does open the door more for Ukraine to target Russia's grid, without worrying about taking down the grid for Baltic NATO members who they would not wish to anger.
What is the point you're trying to make with this? Majority of the cost of electricity in the Baltics come from taxes and distribution fees – these well exceed 5 cents by themselves – just like elsewhere in the EU. None of the Baltic countries actually trade electricity with Belarus or Russia for quite some time either, so if there is an effect on prices due to synchronizing with the EU infrastructure, it is going to be minimal. In fact the spot market price already follows the capacity in Sweden & Finland quite closely.
As another data point, the electricity price was already ~16 cents/kWh 10 years ago and ~12c/kWh in 2009. High despite trading with Russia being a thing back then.
Did they consider connecting to both grids at the same time making a bigger 'supergrid'?
If there is insufficient connectivity between the grids and the connections all disconnect due to overload, you just end up back in the two-grids situation that they have planned anyway.
BRELL ring is a tool to manipulate the baltics energy system and pressure them politically. Namely, it is used as a “last resort” balancing system where fast response river Volga cascades are able to eat the surplus (stop producing) or provide enough in case of shortages. Balancing energy is the most expensive and there is really no good way to bound/hedge the costs. Hence a tool to manipulate the baltics. In addition to that, this will allow the baltic countries to finally move onto more liquid and cheaper 15min day-ahead, intraday markets.
There's by now a lot of DC links in Europe for example going from the European continental grid to the Nordic grid. Denmark is split between the two so it has a country internal DC link too.
There are several DC links in Canada too, i.e. the underwater link between the Lower Mainland of British Columbia and Vancouver Island, which uses only one conductor and the water itself as the other. The North American grid is also DC linked betwen Alberta and Saskatchewan at one point.
DC links solve a myriad of synchronization problems.
At one site in a jungle, my employer had an electrically driven flywheel built that ran on that country's mains grid, paired with an AC alternator on the flywheel that fed the building. This solved a variety of frequency and voltage problems, including mains outages. If the mains went dark, a diesel generator would kick in to boost the flywheel RPMs on an as-needed basis rather than constantly run.
Yes it's some physical connection being broken. It's not unusual to adjust the ways in which the electrical grid is connected. See https://www.youtube.com/watch?v=7Q-aVBv7PWM from Practical Engineering which talks about some of the nuances of building switches which can break connections between different parts of the grid safely.
The frequency is a key parameter of the grid. If there is too much load, it goes down, and if there is too much production it goes up. A lot of critical grid infrastructure relies on the frequency being in the 49.5-50.5 Hz range.
I built a tool together with some colleagues to track the grid frequency in real time during this operation over the past few days to follow this process in real time!
If you're curious for more details, there is also a great post on the Estonian TSO's website about the process: https://elering.ee/en/synchronization-continental-europe