Question: In the aftermath of the recent storms in the UK, one of my neighbours reported a flash and loud bang from his local transformer station, and the power briefly cut out. 

After that, several households reported their appliances malfunctioning, including a hair-dryer getting dangerously hot, the smell of burning from sockets and boilers and Xboxes no longer working. The power company cut off power while they investigated and are now repairing/replacing everyone’s appliances at their expense. 

So what would have caused this to happen? I can only imagine a spike in voltage as I understand that breakers and fuses blow on too much current, but I can’t believe there aren’t some safety mechanisms to prevent this from happening.

Answer: 
We have a [HNQ question on that](https://diy.stackexchange.com/questions/185036/why-is-my-voltage-dropping-with-load-and-why-is-current-flowing-on-my-ground-wir/185045#185045) right now over on diy.stackexchange. 

That problem is a *little* different since that person gets 2 phases (hot-neutral-hot), and most UK homes get only one (hot-neutral). But your situation is **absolutely identical** to my own situation last year -- we're an outlier for the US, but our units get *single* phase just like you (of course, it's 120V), but our estate is served by split-phase (2 phases of 120V each). Half the flats are one one phase, the other half are on the other phase. 

Split phase power is a line - 240V "long" with neutral in the middle. So it's very easy to see the behavior of a lost neutral; each phase is higher or lower than 120V, *but the dead giveaway is, they add up to 240V*. 

We lost our neutral wire. So our flat was (tending to) see voltages go down to 80 volts, but simultaneously, half our neighbors were seeing 160 volts. So they blew a bunch of appliances. I figured this out because my storeroom is on the other "leg" so I was able to run over there and measure 145V. (uh oh!) Our voltage was lower because our "team" was in a tug of war: by pulling more current, we were pulling neutral closer to us, lowering our voltage and raising theirs. 

It's your exact same situation with the "tug-of-war", except 3 teams instead of 2, and **your playfield is a triangle**. You occupy one corner of the triangle. The triangle is 416 volts on a side, with 240V to the dead center of the triangle. That dead center - neutral - has become un-pegged. If your team uses more current, you are pulling neutral toward your corner, raising voltage for the other teams. The highest possible voltage is 416V. 

If the transformer is wired correctly, current will also try to return through your earthing system (the grounding electrode system in North American parlance) which will tend to pull neutral back toward the middle. That's how the linked question had less extreme voltage shifts than you might have expected, and why there was current moving on the grounding electrode. If your transformer's connection between its neutral and its earthing system is broken, that won't apply, and voltage shifts can run the full gamut clear up to 415V. 

In the UK and the five continents which are not North America, most consumer power is wired so each flat gets neutral plus one of the three phases of power.
Sounds like either a step down transformer failed and you all got a seriously high voltage and current spike, or it was a lightning strike on the power station.

In either case the surge would likely have shorted out insulation on things like motors. The voltage might well have jumped into the tens of kV briefly. However unlike "normal" surges this would have been accompanied by very high currents.

So, all the breakers fuses etc might well blow, but too late to save some bits of connected equipment.

You could try buying surge protectors, but domestic ones are only rated for quite low energy events. Sticking 10kV at a few hundred amps across it for more than a few milliseconds would have destroyed that as well.