Grid Congestion

What joined up thinking ?  So far it has grown like Topsy, and the design, such as it was has, like the nederlands, all been assuming blobs of central generation and a radial distribution grid where the voltages get lower and or the cables get thinner,  towards the outskirts. There is also an assumption, which no longer holds with domestic generation, that the voltage drops and available fault energy, are all downhill all the way moving out from generation to consumer.

The reversal of that voltage drop, as what was once the small tail expands and wags the dog is another problem.

The joined up thing to do as while up-sizing the outer reaches of the grid as cables and transformers are installed or come to end of life, would where  practical be to keep the cable cross-section  the same and increase the line voltages - which would not be possible in all cases, and may require some re-evaluation to see which types of 11kV cables could run at perhaps  19kV (11kV line to ground  rather than line to line) and which sorts of LV cable could be run at 400V or 690 instead of 230/400.
Probably includes making the UK default domestic incomer 32A phase rather than 100A single - a partial elimination of the neutral half of the voltage drop in either direction has got to help.

Redefining the LV limit to include 690/1k3 might help as it would make the installation of larger area or high  sites (thinking solar farms and maybe places with lots of EV chargers and so on) possible as a more "normal electrician" activity, rather than the voltage desert we currently have between 1kV (top end of LV) and 6k6, which is the lowest used by any UK DNO leading to very fat cables for reasons of voltage drop (I'm ignoring channel islands HV systems, as they are a law unto themselves, literally).

It is surprising how far how many kVA can be sent over a cable how thin, once one allows this paradigm shift - I remember about 25 years ago, being  very impressed in Germany (well it would be wouldn't it) by an industrial 690/1k3 system with cables about the size of 2.5mm SWA running the full length of a massive hanger-like production facility (more than half a km), and realizing that here with 230V it would probably have had two or more DNO substations and supply points and a rash of worries about earthing and metering.

Mike.

What joined up thinking ?  So far it has grown like Topsy, and the design, such as it was has, like the nederlands, all been assuming blobs of central generation and a radial distribution grid where the voltages get lower and or the cables get thinner,  towards the outskirts. There is also an assumption, which no longer holds with domestic generation, that the voltage drops and available fault energy, are all downhill all the way moving out from generation to consumer.

The reversal of that voltage drop, as what was once the small tail expands and wags the dog is another problem.

The joined up thing to do as while up-sizing the outer reaches of the grid as cables and transformers are installed or come to end of life, would where  practical be to keep the cable cross-section  the same and increase the line voltages - which would not be possible in all cases, and may require some re-evaluation to see which types of 11kV cables could run at perhaps  19kV (11kV line to ground  rather than line to line) and which sorts of LV cable could be run at 400V or 690 instead of 230/400.
Probably includes making the UK default domestic incomer 32A phase rather than 100A single - a partial elimination of the neutral half of the voltage drop in either direction has got to help.

Redefining the LV limit to include 690/1k3 might help as it would make the installation of larger area or high  sites (thinking solar farms and maybe places with lots of EV chargers and so on) possible as a more "normal electrician" activity, rather than the voltage desert we currently have between 1kV (top end of LV) and 6k6, which is the lowest used by any UK DNO leading to very fat cables for reasons of voltage drop (I'm ignoring channel islands HV systems, as they are a law unto themselves, literally).

It is surprising how far how many kVA can be sent over a cable how thin, once one allows this paradigm shift - I remember about 25 years ago, being  very impressed in Germany (well it would be wouldn't it) by an industrial 690/1k3 system with cables about the size of 2.5mm SWA running the full length of a massive hanger-like production facility (more than half a km), and realizing that here with 230V it would probably have had two or more DNO substations and supply points and a rash of worries about earthing and metering.

Mike.

There is also an assumption, which no longer holds with domestic generation, that the voltage drops and available fault energy, are all downhill all the way moving out from generation to consumer.

A lot of the latest domestic PV inverters come with a battery, so to maximise on-site self-consumption -  presumably that approach would help alleviate some of these problems. With a bit of extra control it might even be possible to target the battery output to periods of high grid demand (e.g. don't let the battery start discharging as soon as the sun goes in, but wait for the evening peak) even if it didn't export as such it could still have a benefit of removing some load from the local pubic grid.

   - Andy.