From time to time, when people are discussing the consequences of power outages, like the ones from the Texas winter storm or a hypothetical catastrophic space weather event (Carrington event scale), someone invariably brings up the point that one of the most important goals during a power crisis is to ensure that the high voltage transformers do not get damaged, because even with our current technology, it easily takes well over a year, probably even over 2 years, to build just one.

Why would it take so long to build one of these? Are they that complex to assemble?

  • \$\begingroup\$ how many kVA? which type? \$\endgroup\$ May 6 '21 at 11:47
  • 1
    \$\begingroup\$ @PaulGhobril, OP is reasonably quoting from the news, where they don't usually put detailed technical specs. \$\endgroup\$
    – TonyM
    May 6 '21 at 11:57
  • \$\begingroup\$ I think you're going to get lots of speculation and 'informed guesswork' answers. If you'd written 'why does it take a fortnight' or 'why five years', you'd get the same 'well obviously, because' answers. I hope you get a definitive one from someone with actual knowledge and experience of the industry. \$\endgroup\$
    – TonyM
    May 6 '21 at 12:14

A geomagnetic storm of the magnitude seen during the carrington event would lead to massive induced currents in long distribution networks. The longer the network, the more induced current. As such the networks that are most at risk are the large international networks, typically several hundred kV or more. These are custom built, at site, with literally truckloads of equipment.

While it is unlikely that it will be completely destroyed it will almost certainly be significantly damaged, and you can not simply ship a new one based on off-the-shelf equipment. It has to be build up from scratch.

Smaller stations will also be affected, but these are simple enough to rebuild. But: In a Carrington event there will be an immediate shortage of raw manterials and production capacity, that will be amplified by the fact that the locations building these parts could be without power themselves.

A powerful geomagnetic storm terrifies me. I have absolutely no faith in the current pro-forma testing and conceptual unverified protection mechanisms. Our modern society has never, ever, experienced a geomagnetic storm of those magnitudes. As seen during the current Corona crisis the experts can wave all the red flags they want, but in practice no proper action is taken.


IMHO there are a lot of reasons:

  • They are big, unwieldy and expensive (there is lot of material inside, special isolation and manual work) - on the other hand, when constructed, they last like nearly forever - so building them on shelf means put lots of resources to something, which would not sell soon - so nobody has built lot of them to shelves
  • There is a constant improvement in science, so the probability, that after like 10 years there would be better/cheaper technology - as well as that there much larger power would be requested - is high, and so again it means less willingness to make them to sit for years on shelves, blocking lot of resources and space, and then be over expensive, obsolete and weak
  • so with no transformers on shelves, when one is needed, it is ordered to current specification, when the place for it is planned - it does not matter so much, that it would take lot of time to do it, the construction of the place will also probably take long time to build
  • The transformer is in theory simple, but in practice there must be first done the core, which is not simple or fast task, then the wiring, which needs lot of care and very good (and expensive) isolation (as there are really high voltages), which need also to "dry" for long time to get the right quality. Also it need extremely strong construction, as there are extremely strong electric and magnetic currents, which tend to periodically vibrate all those wires and core with extreme force.

And should some catastrophe hit, there would be big risk, that not one, but many transformers would be damaged and so would need replacement (It is easier and faster to a build new one, than repair one damaged).

As you mentioned Carrington event - it put telegraph lines to massive fail - now the electric lines are much longer and much more of them, so the consequences would be much stronger too.

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    \$\begingroup\$ This is just speculation that many could have written. This answer works backwards from the reported fact that it does take ages to make them, using common knowledge and guesses to do so. There's no industry knowledge or actual experience here. Downvoting accordingly, I'm afraid. \$\endgroup\$
    – TonyM
    May 6 '21 at 12:10

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