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## Is it real to simulate Full Lightning Impulse 1,2/50 us in Comsol 4.0?

Hi

I simulate electric fields in high-voltage switchgear.

In my models I use AC/DC Module Electrostatics (es).
If the electrode is under high potential, the boundary condition for that electrode will be Electric Potential with fixed Voltage value.
So, as a result, I get the static electric field distribution.

My aim is to simulate the influence of time dependent voltage namely Full Lightening Impulse 1,2/50 us.
It has form shown on the fig. 1 in following document:
eprints.soton.ac.uk/48555/1/Swaffield_ISH_conference.pdf

The duration of impulse is 50*10e-6 s. As you see it is very short.

So, here is the question.
How can I simulate the model with such time dependent voltage applied to the electrode?

5 Replies Last Post Feb 9, 2013, 10:40 AM EST
Posted: 7 years ago
Hi

first of all see with your rep or sysadmin, and update to the latest version, there are many weaknesses in the early 4.0,
then for such a pulse why not write out the pulse shape as a smooth (1-2 derivable) analytical function, and multiply your peak voltage by this function of the time "t". Then select a time range covering correctly the pulse, and use a "time step" definition such as Intermediate or strict (not automatic), I believe that would work better, but your single pulse could perhaps also use automatic, as it has a long decay shape. And for me off you go ;)

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Good luck
Ivar

Posted: 7 years ago
Try with smoothed Heaviside function:

U * [ ( flc2hs (t - 0.6us, 0.6us) - ( flc2hs (t - 50us, 100us ) ]

In Comsol 3.4 and 3.5a this function worked fine but I didn't use this formulation in Comsol 4.

Posted: 5 years ago
Hello Roman,

Did you able to successfully simulate the full LI in comsol? If yes would you please let me know the parameters? I was also trying to do but without any success.

Good Day!

Keyur

Posted: 5 years ago
Hi

the flc2hs() are replaces in V4 by the predefines "Definition - Functions - Step or - Rect or ... operators

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Good luck
Ivar

Posted: 5 years ago
Hallo. The impulse voltage shape for 1,2/50 us can be successfully set in Comsol 4 in Global Definition with help of Functions->Analytic. Here the Argument is time "t". For checking your impulse shape just click "plot". In the Magnetic and Electric Field study (mef) u should use Terminal for injection of this voltage impulse. If function name is impulseShape then in Terminal it should be putted impulseShape(t). Also dont forget about redefining your steps under study sets.

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