Mains power voltage drop to reduce usage?

In the f****ng insulator in the wire you OCD f****it. Go back to sleep.

We know that. However, copper does have a dielectric constant. Its just very large - and complex.

John

BMW is the worst. The word tailhappy is a synonym of BMW.

So, to get back on track.... capacitance of an underwater line vs. an overhead line....

It is not irrelevant at all. Overhead, high-voltage wires are uninsulated. Underwater ones cannot be and also have to have physical (metal) protection. That alone turns them into very long capacitors.

Or any other hard substance.

Make the insulater thicker?

Or what if you let the sea be the live voltage?

Or we could send a f****ng powerfull laser beam through the air....

Transmission lines, actually.

"Transmission lines" in the electronic meaning, with a characteristic impedance, not just capacitance.

So, tracks need overpass or underpass for most road crossings. And, faltering trains need to get off the main tracks somehow (sidings, the provisions are called). There's always solutions to problems.

Which is a kind of waste of resources? But, the man-hours of time available to passengers because they don't have to steer, brake, etc. is a major savings. Goods and materials traveling via train are effectively reducing road wear, congestion, and travel time a LOT just by spreading goods from their point-of-production.

An old diary entry told of a couple who wanted to enjoy some cream, who had the servants take them by carriage to a dairy... ice cream is available at all our little groceries because we do NOT need to buy local.

Yes. When I visited as a teenager the very first UK-FR undersea link, the engineers said 'if we switch it off and disconnect it, we can draw an arc for half an hour from the stored electricity'.

Seawater is a good conductor, unlike air, so the cables must be insulated, and that insulation forms the bulk of the dielectric.

That's why they had to be DC - charging and discharging that capacitance via a resistive cable cant be done 50 times a second without massive losses.

Are all insulators dielectrics?

Potentially.

It seems to be a symptom of the rail industry at present that someone needs to attend in person to reboot, instead of the person who is already on-site (the driver) being able to do it (with suitable checks and authorisation first).

It's like the events leading up to the Stonehaven crash when a signaller was not able to move the points to switch the train from one track to another, but instead the train had to wait for a signal technician to drive there to move the points. Have whatever safety checks are necessary, but once those have been passed, give the person on site the authority to restart things without waiting for people to attend from elsewhere.

That's what's wrong with the rail industry: too much emphasis on process, and not on "just f-ing do it". The needs of passengers are paramount.

But they didn't know that at the time so they shed the right amount of load but because that also dropped a lot of local generation as well they were forever playing catch up. The grid didn't respond as expected when they shed the 1GW because then net shedding was only 400MW.

It took them time to realise what was happening and by then they were forced to shed even more load to regain control. They managed to rebalance the grid and get the frequency back in tolerance in under 5 minutes which isn't bad going but they had to drop off rather more load than was strictly necessary because of the way that local generation has altered the rules of the game.

If you're gonna start on that, the superconductor left without resistance.

Just what checks are needed to turn it back on because of a powercut? Clearly a driver already knows how to see where other trains are. In fact if a diesel train was oncoming, he'd be a lot safer being able to start it!

But "a signaller was not aware of any obstruction on the line." -

The same should apply to the police at a road accident.

If it's automatic it should have been a couple of seconds surely?

So the idiot in charge had never heard of local solar generation.

Ability to form a capacitor is connected to the formation of dipoles in the material Monopoles are characteristic of conductors.

There must be some insulators which cannot form dipoles.

What happens if they simply lower the Pantograph? I suppose they do that eventually, when parked.