Question
The valid positive, negative and zero sequence impedance (in p.u.), respectively, for a 220 kV, fully transposed three-phase transmission line, from the given choices are
Options :
0.15, 0.15 and 0.35
0.2, 0.2 and 0.2
1.1, 0.15 and 0.08
0.1, 0.3 and 0.1
Answer :
0.15, 0.15 and 0.35
Solution :
In case of transposed transmission lines
Zero-sequence impedance, X0 = XS + 2Xm
Positive-sequence impedance, X1= Xs- Xm
Negative-sequence impedance, X2=Xs- Xm
So for transmission line, X1= X2<X0
In option (A) only have, X1=X2=0.15
X0=0.35
Hence, the correct option is (A).
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