The Y_bus matrix of a two-bus power system having two identical parallel lines connected

between them in pu is given as $Y_{b u s} = [\begin{matrix} - j 8 & j 20 \\ j 20 & - j 8 \end{matrix}]$ .
The magnitude of the series reactance of each line in pu (round off up to one decimal place) is ____________.

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Answer 1

$y_{B U S} = [\begin{matrix} - j 8 & j 20 \\ j 20 & - j 8 \end{matrix}]$

Let series impedance each line is jy pu

D233

From y_BUS, Y₁₂ = - y₁₂ = j20

⇒ y₁₂ = -j20

From the diagram

$y_{12} = - \frac{j}{y} - \frac{j}{y} = - \frac{2 j}{y}$

$\Rightarrow - \frac{2 j}{y} = - j 20$

⇒ y = j 0.1 pu