Question

A 100 kV, 2 micro sec rectangular surge on a line having a surge impedance of 300 $\Omega$ approaches a station at which concentrated earth capacitance is 3000 pF. The maximum value of transmitted value is___kV.

• A. 178.32

Answer 1

The correct option is A 178.32

$V"=V.\frac{2Z_2}{Z_1+Z_2}$

V'' is transmitted wave/refracted

V is incident wave.


$V"=\frac{\frac{V}{S}.2.\frac{1}{CS}}{300+\frac{1}{CS}}$

$V"=\frac{2.\frac{V}{S}.\frac{1}{3000\times {10}^{-12}S}}{300+\frac{1}{3000\times {10}^{-12}S}}$

$V"\left(S\right)=\frac{2.\frac{1}{CS}}{Z+\frac{1}{CS}}.\frac{V}{S}$

$V"\left(t\right)=2V(1-e^{\frac{-t}{ZC}})=2\times 100(1-e^{\frac{-2\times {10}^{-5}}{300\times 3000\times {10}^{-12}}})=178.32kV$