Continental europe having problems with 50Hz

[Andy Burns]

They've lost 5 minutes worth of cycles since mid-January

[newshound]

Seems surprising.

I'm not sure if the continental grid is kept synchronised across all countries. In the UK, any daily lag is usually fixed overnight.

[Andy Bennet]

Good job the interconnctors are DC!

[T i m]

I didn't know / imagine that (or guess why)?

Cheers, T i m

[Chris Hogg]

AIUI short-distance undersea interconnectors are sometimes AC, but long-distance ones are almost always DC, because they experience significant capacitance* losses if AC due to being surrounded by an earthed conductor, i.e. salt water.

*but might be inductance. IANAE

[Chris Green]

It's exactly *why* they're DC as I understand it, the difficulty of synchronising our grid with the French grid.

For longer cables DC makes sense for other reasons but for the 25 odd miles across the channel I'm pretty sure it was the synchronisation issue that was the reason for using DC.

Weren't they originally huge mercury arc rectifiers or is that just my wierd imagination? :-)

[Martin Brown]

I am a bit surprised they have let it drift quite so far though. I guess it must have been very cold everywhere and they lacked any spare capacity to catch up even in the quiet hours of early morning.

It is even more important in Japan where the east half the island is on UK 50Hz mains and the west half on US kit at 60Hz. The voltage is also non-standard at 100v which makes it marginal for real US kit to work.

[The Natural Philosopher]

[The Natural Philosopher]

Not usre there are ANY undersea AC links

It is capaacitance that kills - power factor is vile and that leads to large out of phase currents which heat the cable up

[The Natural Philosopher]

No, it is losses.

Yes.

[Dave Plowman (News)]

We've not maintained our average either - if the mains locked digital clock I have here is to be believed. It is now further out than at any time since I've had it.

[Martin]

How much has UK paid for French electricity and foreign gas. What happens if Russia turns off the flow of gas to UK? Something a bit more relevant to worry about in UK.

[dennis]

Not much because we don't get much gas from Russia. Now if Russia turned off its gas to the rest of its customers the price would rocket.

[Brian Gaff]

Yes well, I whenever convinced it was that accurate since I saw hum bars rolling down tv screens in the 1960s.

I blame the solar inputs from invertors myself. Brian

[Chris Hogg]

The interconnect between the small Danish island of Bornholm in the Baltic and Sweden is AC. Admittedly it's only a 60KV 60MW link, but it's submerged for 43.5km. It's the one I had in mind, but it's actually longer than I realised.

[Brian Gaff]

I was actually thinking that I'd imagine powe cuts were the biggest annoyance to clocks that cound mains cycles myself, not a slight loss due to cycles.

Brian

[T i m]

Thanks Chris, it makes sense.

Cheers, T i m

[newshound]

Indeed. According to Wikipedia, the largest were rated at 270 MW (the main French interconnector is 2000 MW

"However, starting about 1975, silicon devices have made mercury-arc rectifiers largely obsolete, even in HVDC applications. The largest ever mercury-arc rectifiers, built by English Electric, were rated at 150-kV,

1800 A and were used until 2004 at the Nelson River DC Transmission System high-voltage DC-power-transmission project."

[Andrew Gabriel]

Before the Berlin wall came down, there were two continental Europe synchronisation zones, Western Europe run from Switzerland, and Eastern Europe run from Moscow. The first was +/- 0.1Hz, the second was +/- 1Hz, IIRC. The western side was actually very short on spare capacity (particularly Germany), and the east had lots, but from highly poluting sources. When the wall came down, Germany was in a dilema at the time on using power from the east which Western German industry desperately needed, but seriously pumping up the resulting polution.

I haven't seen a good write-up since the political geography changed.

[The Other Mike]

Isle of Man to Bispham near Blackpool

40MW at 90kV 104km (longest in the world)

Spain to Morocco

600MW @ 400kV 27km