Uh Oh. first Bilsdale, now Kent Interconnector

Well, I've often wondered how come some of those cross channel cables have not developed faults before now, however will anyone look at the eggs in one basket issues of telephones, power etc, which are being made at the moment? Of course not till it bites us all in the bum. Brian

An interesting point about these interconnecotrs is that they are DC.

SO whats the energy losses like rectifying AC current to DC and again when its converted back to AC?

WWhy do this double conversion in the first place?

Would it not be easier to synchronise the two countries AC frequencies and phase, and also less lossy?

It?s to do with power losses due to cable capacitance over long distances.

From wiki.

?Most electrical power transmission systems use alternating current (AC), because transformers can easily change voltages as needed. High-voltage direct current transmission requires a converter at each end of a direct current line to interface to an alternating current grid. A system using submarine power cables may be less costly overall if using high-voltage direct current transmission, especially on a long link where the capacitance of the cable would require too much additional charging current. The inner and outer conductors of a cable form the plates of a capacitor, and if the cable is long (on the order of tens of kilometres), the current that flows through this capacitance may be significant compared to the load current. This would require larger, therefore more costly, conductors for a given quantity of usable power to be transmitted.?

Tim

ah ha and presumably you'd also have to do some power factor correction.... that would not be trivial to do at high voltage and high current....

And of course the rectification and inversion is all done in solid state these days, so the conversion losses are relatively low, and big transformers are pretty efficient.

No different from at present, there is hardware for power factor correction at strategic points on the existing grid.

SO from P=IV, I = P /V whihc gives a current of 3,125 Amps.

For rectification:

if we assume silicon diodes are used with a junction voltage of 0.6 V and that we assume that a full wave bridge rectifier is used.

lets assume 3,125 amps is flowing through that diode. The power loss across that diode which is lost to heat is going to be 1,875 Watts per diode.

So in a full wave bridge rectifier of 4 diodes, thats 7.5 kW of heat to dissipate..... :-)

S.

Less than some people have in their bitmine rigs at home.

Owain

And you don't call that efficient?

Don;t forget there's actually 3 phases so the heat loss is triple that at 22.5 kW as then 3 sets of bridge rectifiers are needed.

I've not even worked out the losses at the inverter end yet..... :-)

but then it's 3 phase, and I remember reading somewhere they operate as a 12-phase device, probably it'll be using 2 out of 12 diodes/scrs/whatever at any time so a lower duty cycle to spread the heat between them ...

wiki article has some impressive photos

Meanwhile proposals for a new interconnect are not popular with locals.

Consensus seems to be "My bit of Suffolk? No, move it further south or put it in Essex."

This current outage should focus various minds on how few interconnects we have and how much we depend on them.

Cheers

Dave R

This current outage should focus various minds on how many interconnects we have and how little we *need* them.

What we need is nuclear coal and gas.

No, that would be extremely difficult to do reliably. It would mean trying to keep the whole of Europe synchronised with the UK. Large AC grids tend to become unstable.

John

.....but the conservative government missed the best opportunity in the

Interconnects are only of use if Europe has spare capacity. That will not automatically be the case, but some seem to think that Europe will always be there to make up any shortfall in our own generation.

The Natural Philosopher presented the following explanation :

What we need is nuclear. Some gas for emergencies and ZERO coal usage apart from those metallurgic processes where there is no viable alternative.

On 16/09/2021 15:06, Chris Hogg wrote: > some seem to think that Europe will

Bless!