Didcot towers to be blown up

[whole diary]

[infoman]

Well the remainder of them anyway.
Planned for Sunday 18 August 06:00am till 08:000am
Exclusion zones in force

[CyclingSid]

That is not giving much clearance to the right of way closure starting on the same date, which has no published end date.

[CyclingSid]

Gone!
https://www.bbc.co.uk/news/uk-england-oxfordshire-49375917

[bobm]

But now a widespread power cut...

[Oxonhutch]

Heard the boom and missed the cut. Just apparently, as we are within bobm's red area.

Gave them a nod good-bye on the Friday commute home. Still remember the University railway society tour around the complex in 1979? Looked so shiny and new with its immaculate turbine hall, control centre - and of course, Merry-go-Round coal trains. Tempus certainly does fugit these days!

[didcotdean]

Most likely explanation seems to be that the shockwave from the explosion caused wires in the distribution system at Sutton Courtenay to either touch or at least be close enough to arc.

Following photograph from this Oxford Mail article:


Not mentioned in this report was another eye witness who saw the power lines oscillating violently before the electrical explosion.

I was woken by the cooling tower explosion at 7am and noticed the power was off looking at my clock. With me it was restored in around three-quarters of an hour. It was quite a widespread cut affecting even some people with a GL postcode.

[bobm]

Heard the boom and missed the cut. Just apparently, as we are within bobm's red area.

Gave them a nod good-bye on the Friday commute home. Still remember the University railway society tour around the complex in 1979? Looked so shiny and new with its immaculate turbine hall, control centre - and of course, Merry-go-Round coal trains. Tempus certainly does fugit these days!

Reminded me of a school trip around there a couple of years before.

[Bmblbzzz]

I heard it might have been someone flying a drone too close to the pylons, presumably wanting to film the demolition. I don't know if there's any actual evidence for this though. Another possible cause given is arcing caused by dust clouds but this seems unlikely. Oscillation is probably the most likely cause.

Ed: Presumably there will be an inquiry by those who actually know and understand.

[broadgage]

Oscillation caused by the blast wave is IMHO^▸ (in my humble opinion) the most likely reason for the failure, or of course it might be unrelated and simply be coincidence.

The dust cloud seems unlikely to be the cause as the arcing appeared to start before the dust cloud reached the area. Also concrete dust is not conductive, unlike say carbon dust, AKA^▸ (also known as) soot, as might be spread by demolition of say a chimney.

[infoman]

and the local power supplier said,nothing to do with us.

[bobm]

and the local power supplier said,nothing to do with us.

Initially, but then thought there might be a connection.

[stuving]

and the local power supplier said,nothing to do with us.

Initially, but then thought there might be a connection.

Originally SSEN^» (Scottish and Southern Electricity Networks - website) said it was nothing to do with the demolition - implying it was all down to them (if not culpably). Their revised story is (from the updated BBC^» (British Broadcasting Corporation - home page) report):

During the demolition, a large section of debris protection material became detached from one of the cooling towers and made contact with our 33kV overhead line, which was outside of the advised perimeter. This resulted in significant damage to the overhead line and subsequent network faults.

So yes, it's now "them" - RWE, their demolition contractors, safety advisors, etc. - at fault, and somewhat ironic too.

[didcotdean]

These pictures shows how there were many people in the vicinity of the electrical explosion, indeed almost underneath it, as it seemed a good site for parking the car and waiting for the cooling tower implosion.

[stuving]

The overhead lines and fire in the pictures are on Sutton Courtenay Lane (or Road), just north of the Milton substation. These 33kV lines come from the SSEN^» (Scottish and Southern Electricity Networks - website) bulk supply point at Drayton, and used to run further into the field until a few months ago. Presumably they now go underground by the roand so as to allow building on the field. The BSP^▸ (Bulk Supply Point) feeds other 33/11 kV substations as well as Milton, of which Abingdon and Fulscot may be fed via these lines (it's hard to say once they go underground).

If the debris had landed inside the Milton substation (which has no overhead line connections), you'd expect damage that normal protection couldn't prevent. It is about 800 m from the nearest tower, the same as the lines that were hit. I do wonder whether such as fault on a line between substations should have had the result it did - but I don't really know enough to say.

[Bmblbzzz]

SSE^‡(resolve) have now confirmed they, or their contractors, did miscalculate the radius of the risk area from debris. It was flying dust or chunks of concrete that caused the fire.
https://www.oxfordmail.co.uk/news/17844787.didcot-power-station-demolition-debris-hit-power-cables/