# Short-circuit symmetrical components

Discussion in 'General Electronics Chat' started by Larosso, Jan 10, 2009.

1. ### Larosso Thread Starter New Member

Jan 10, 2009
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I start this thread bt saying that allaboutcircuits.com has a great way of explaining rather complex issues.

I am asking if anyone can show me some documentation where the method of symmetrical components is explained in a way it is actually possible to understand, also from a practical point of view.

Anybody out there who can help me with this??

2. ### mik3 Senior Member

Feb 4, 2008
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What do you mean by symmetrical components?

3. ### Larosso Thread Starter New Member

Jan 10, 2009
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When a short-circuit occurs in an installation, and this short circuit is not symmetrical, for instance a "Single-pole short circuit to earth". The there is different mathematical tools to calculate this short-circuit current. I believe the most common method to determinate short-circuit currents is the method of using Symmetrical components.

So I am very interested in finding documentation describing the history of the method, in other terms how do they think when the developed the method, and some examples as well.

4. ### Percent_Impedance New Member

May 14, 2008
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so your talking about like a three phase balanced system.. Then if there were a phase to ground fault what would be the currents in the other two legs. is this what you mean? i understand you want literature but im trying to undestand first.....

5. ### Larosso Thread Starter New Member

Jan 10, 2009
3
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Yes, the case you mention here is an example where you can use the method of symmetrical components. Here is "a part of the method"

IkR=Ik+ + Ik- + Ik0

IkS=h2Ik+ + hIk- + Ik0

IkT=hIk+ +h2 Ik- + Ik0

where–

h= ej120°
h2= e j240°

1+h+h2=0

But I have not found any literature that explains the method in way it is actually possible to understand.

(By the way - I am also interested in documents where there are schetces/drawings of the short circuit path in different fault situations.)