DC component in fault current - X/R ratio

[Cerkit]

Hi,

Can someone explain what the DC component of a fault current waveform is? Is this stored energy in the inductive parts of the network which then dissipates?

Thanks

 

[xnuke]

Yes.

xnuke
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[dpc]

That's one way to look at it. The actual fault current waveform will (in general) not be symmetrical, but rather offset in one direction or the other, due to the inductance in the circuit. It can be thought of as the sum of the symmetrical (steady-state) sine wave plus a decaying dc component that decays at a rate dependent on the system X/R ratio. It is also dependent on the voltage phase angle at the time of the fault, so the magnitude of dc offset varies and may not actually occur if the initial conditions are just right.

 

[Cerkit]

Thanks.

I guess most books just say that, that it is an asymmetric waveform, but never really say much to give an intuitive feel of what is happening.

 

[HamburgerHelper]

Here is a good thread.

http://www.eng-tips.com/viewthread.cfm?qid=192667

 

[charz]

Another thread to look at,

https://www.eng-tips.com/viewthread.cfm?qid=422436