Mains frequency isn't a good clock, since it's a moving target by its nature. Frequency rises when source exceeds load. Frequency drops, when load exceeds source. Frequency is feedback for the operator to add or reduce the source power. It's like a car on cruise control, when encountering hills.
it *used* to be an excellent clock--utilities used to guarantee 5,814,000 cycles of 60hz each day (although the exact frequency would vary throughout the day). electric clocks used to keep very good time because of that.
tl;dr estonia, latvia, and lithuania are switching from russia's power grid (a holdover from when they were part of the soviet union) over to the EU's power grid.
seems like quite a tricky operation. they're going to be their own "power island" for a number of hours, operating independently on their own power plants, before adjusting their line frequency and phase and closing the switches that connect them to the EU grid.
those are named Estlink 1 & 2 (2 is the one "someone" cut last year)
1 is 150 kVDC, 350MW. Finnish grid is 400kV AC, Estonia 330 kV AC and in different sync.
2 is 450 kVDC, 1400 A (~650MW)
There's the "Open Infrastructure Map" site. It shows all the generating facilities and the distribution lines, AC and DC< with the voltages. https://openinframap.org/#2/24.73/-45.66
The search term you're looking for is "HVDC interconnector" - it finds examples all over the world where two independent AC grids can transfer energy to each other over a DC link.
I'm still amused in mild difference in coverage between Estonia and here in Latvia; former advising to just in case have up to a week worth of food and water, while latter insisting to do as much as possible to not disrupt normal routines xD
That is going to be an interesting power grid to watch. I also hope somebody does an after action report so I can see how this went. Because that's a non-trivial operation. And power is going to be funny for most of Europe if they aren't careful.
Don't read too much into the large swings: they are likely deliberate to test system safety features whilst they have the rare opportunity of being decoupled before reintegration to the EU grid
This is fascinating. So many factors to consider! From Power factor (VA, VAR, inductors and capacitors), right down to synchonous and asynchronous motors (RPM of rotating field is tied to the grid frequency when not using AC drives)! Huge undertaking!
That's how they currently connect. The big fuss is the fact that they have two entirely different frequencies and they honestly shouldn't at this point in time but it would take too much to redo half of it.
One big plus that we got out of Japan's two inconsistent grid frequencies, is that frequency-agnostic electronics are the industry norm. I have a feeling that Japanese engineers needing to build for both frequencies, motivated a frequency-agnostic design criteria, to sell in both Osaka and Sapporo.
It is a small deviation. Typical frequencies a "healthy grid" are within +/- 0.5 Hz of nominal, and it isn't until the deviation exceeds 1 Hz, for it to be cause for concern.
The US uses 120/208V and 277/480V as its 3-phase options, depending on the service size. The EU uses a compromise of these two, at 230/400V. In all cases, the utility-level voltage is much much higher (tens of kilovolts)
Comments
1 is 150 kVDC, 350MW. Finnish grid is 400kV AC, Estonia 330 kV AC and in different sync.
2 is 450 kVDC, 1400 A (~650MW)
https://openinframap.org/#2/24.73/-45.66
One of my old employers, although I was doing IT consulting and not this HVDC cleverness.
https://www.hitachienergy.com/news-and-events/customer-success-stories/estlink
https://youtu.be/bij-JjzCa7o?si=iwtrdtBHcUk0sO0y
(For those unawares, Japan has two grids. One at 60hz, one at 50, with the whole thing bridged by one very complicated mess.)
connect to Poland tomorrow I think?
Not great, not terrible.
I was gauging off the North American 60Hz.
That’s a pretty small deviation no?
While this is a little weird, this isn’t really something I’m concerned about
Likely a statistical event the developers never expected. Nothing malicious.