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Author Topic: What are the usual causes of power cuts?  (Read 10311 times)

Offline techmind

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What are the usual causes of power cuts?
« Reply #25 on: 05/02/2009 00:02:31 »
There can be all sorts of reasons for power-cuts, and it does depend where you live - even within the UK.

The most drastic case is a major failure in generation somewhere (or a completely unexpected or excessive surge in demand) which causes demand to greatly exceed supply. If this arises, the power companies have little choice but to employ "load shedding" where houses/businesses are deliberately cut off so as to make demand equal supply. This is fairly rare in the UK, but has happened once or twice in the past 18 months or so when there were a couple of simultaneous serious generation-failures.

If you live in the countryside with electricity delivered via long lengths of low and medium-voltage powerlines on poles (240/415V, and 11kV) then windy weather and/or overhanging trees can cause the wires to short resulting in flickering lights followed by the eventually tripping of a fuse or circuit-breaker.

If living in more urban areas, then I'm sure contractors digging holes and cutting through cables is a significant cause of power-cuts.

In urban areas there is sometimes redundancy where the low-voltage (240/415V) circuit can be fed from more than one transformer and upstream supply. A few years ago a fairly significant local transformer in my area failed for some reason, and several hours later the engineers came round opening up manholes and patching in new fuses to make a different circuit. They did this with the power 'live'. Was very tempted to switch on every single device in the house to ensure they got the biggest spark when they put the fuse in!

There's not much to go wrong with transformers, although if something happens to the coolant oil then they can overheat and fail.

In the event of solar storms, the earth's magnetic field can be disturbed and this can induce huge DC currents in very long-distance powerlines. This can cause big transformers to go into magnetic saturation and then they become hugely lossy and will rapidly overheat if you still try and force AC power into them. This caused widespread blackouts in the USA and Canada a few years ago.

So lots of causes.
 

Offline erickejah

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What are the usual causes of power cuts?
« Reply #26 on: 05/02/2009 04:09:46 »
In the event of solar storms, the earth's magnetic field can be disturbed and this can induce huge DC currents in very long-distance powerlines. This can cause big transformers to go into magnetic saturation and then they become hugely lossy and will rapidly overheat if you still try and force AC power into them. This caused widespread blackouts in the USA and Canada a few years ago.
interesting  :o
 

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What are the usual causes of power cuts?
« Reply #26 on: 05/02/2009 04:09:46 »

 

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