A lossless transmission line having surge impedance loading (SIL) of 2280 MW. A series capacitive compensation of 30% is emplaced. Then SIL of the compensated transmission line will be
A lossless transmission line having surge impedance loading (SIL) of 2280 MW. A series capacitive compensation of 30% is emplaced. Then SIL of the compensated transmission line will be
Right Answer is:
2725 MW
SOLUTION
Let characteristic impedance
$\begin{array}{l}({Z_C}) = \sqrt {\dfrac{Z}{Y}} = \sqrt {\dfrac{1}{1}} = 1{\text{ PU}}\\\\{\text{ = }}\sqrt{\dfrac{{{Im}pedance/Km}}{{Admittan ce/Km}}} = \sqrt {\dfrac{X}{B}} \end{array}$
Given that, for a given line 30% series capacitive compensation is provided. Hence the series impedance of the line is 0.7 or (70%) of the original value.
$({Z_{new}}) = \sqrt {\dfrac{{0.7}}{{1.0}}} = \sqrt {\dfrac{1}{1}} = 0.836{\text{ PU}}$
Surge Impedance loading = (V2/Zc)
SIL ∝ 1/ZC
(SIL)2/(SIL)1 = Zc1/Zc2
(SIL)2 = (1.0 × 2280 × 106)/(0.836)
(SIL)2 = 2725 × 106
(SIL)2 = 2725 MW