what is the Most likely fault reason for Transient overvoltage on the supply?

[paulthemagpie]

hi guys,

could you give me some help to see if im on the right track with this questions:

what is the Most likely fault reason for Transient overvoltage on the supply?

I was going to say they are usually caused by electromagnetic induction when switching on or off inductive loads (such as electric motors or electromagnets)

 

[Silly Sausage]

Lightning.


You're right spin. Note to self, read the question properly!

 

[Deleted member 26818]

It would appear that the question is asking for a 'fault condition' that would produce transient overvoltage.
I would not have thought that functional switching, or even lightning would be considered as fault conditions.
However, if it is not asking for a 'fault condition', then yes any switching that would produce electromagnetic induction such as switching off discharge lighting etc.
I would have thought the most likely cause, would be where more than one circuit are run in close proximity.
The switching off of one circuit producing the overvoltage spike in an adjacent circuit.
The switched circuit being one with a high load.

 

[paulthemagpie]

got confused for a minute thought you wrote lighting. lol

would lightning be the most likely cause though?

 

[Richard Burns]

From the question it is asking about the supply which might indicate considering network problems, which I would have thought a bit out of scope based on your training, but then the abrupt loss of demand could cause a transient overvoltage.

However with in an installation the same can occur on a reduced scale, just depends on how transient is transient: micro seconds, milli seconds or seconds?

What is the background to the question so as to gain some context?

 

[Engineer54]

I would not have thought that functional switching, or even lightning would be considered as fault conditions.

​

Why would you not consider a lightning strike or discharge, a Fault Condition?? Not exactly a normal or every day occurrence. And from my experience of lightning strikes, they can certainly do a great deal of damage, transient over voltage only being one such an instance...
​

 

[MarkieSparkie]

On average there are 300,000 lightening strikes per year in the UK according to the Tornado and Storm Research Organisation (TORRO), so Lightening Electromagnetic Pulse effects are likely to be a major source of transients on the supply network. The second most likely source is Switched Electromagnetic Pulse effects from switching high current industrial plant connected to the supply network. A third source is likely to be unintentional short-circuits of equipment connected to the supply network. A fourth source is the cumulative effect of harmonics generated by the use of Switched Mode Power Supplies (SMPS), welders, x-ray & magnetic resonance imaging, motors, drives, converters and controllers.

 

[Engineer54]

On average there are 300,000 lightening strikes per year in the UK according to the Tornado and Storm Research Organisation (TORRO), so Lightening Electromagnetic Pulse effects are likely to be a major source of transients on the supply network. The second most likely source is Switched Electromagnetic Pulse effects from switching high current industrial plant connected to the supply network. A third source is likely to be unintentional short-circuits of equipment connected to the supply network. A fourth source is the cumulative effect of harmonics generated by the use of Switched Mode Power Supplies (SMPS), welders, x-ray & magnetic resonance imaging, motors, drives, converters and controllers.

And the list goes on an on.... lol!!!