Compare : Symmetrical Faults & Unsymmetrical Faults

In this article, the comparison between Symmetrical Fault and Unsymmetrical Fault is given.

Symmetrical Fault – Unsymmetrical Fault

Symmetrical fault

• A fault which gives rise to symmetrical fault current is called as symmetrical fault. 
• Equal fault current with 120 degree displacement. 
• Three phase lines are simultaneously short circuited or three phase to ground fault is an example of symmetrical fault. 
• Only one phase is considered for calculation, condition for remaining two phases are remains same. 
• Rarely occurs. 
• The symmetrical fault is rarely occurring and most severe.

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Unsymmetrical fault

• A fault which gives rise to unsymmetrical fault current is called as unsymmetrical fault. 
• Magnitude of fault current are different with equal phase displacement.
• Unsymmetrical faults are ( 1 ) single line to ground fault ( 2 ) Line to line fault ( 3 ) Double line to ground fault. 
• Majority of the fault on the power system are unsymmetrical in nature.
•  The solution of the unsymmetrical fault analysis is done either by ( 1 ) Kirchhoff’s Law or ( 2 ) Symmetrical Fault Analysis.