Question

For a long transmission line, a single circuit 50Hz, $3\varphi$ transmission line has the following parameters per km, R = 0.4$\Omega$, L = 1.6 mH, $C=0.02\mu F$. The voltage at receiving end is 132kV. The incident voltage to neutral at the receiving end (reference) with the line is open at receiving end is____kV.

• A. 38.1

Answer 1

The correct option is A 38.1
$V=\frac{V_r+I_r{Z}_c}{\underset{}{2}}{e}^{\alpha x}{e}^{j\beta x}+\frac{V_r-I_r{Z}_c}{2}{e}^{-\alpha x}.e^{-j\beta x}$
Incident voltage

at receiving end x = 0

$Theincidentvoltageneutralatthereceivingend=\frac{V_r+I_r{Z}_c}{2}$

$Sinceitisnoload,I_r=0$

$Incidentvoltage=\frac{V_r}{2}=\frac{132\times 1000}{\sqrt{3}\times 2}=38.105kV$