Shunt capacitance is neglected while considering Short transmission line.
When analyzing a short transmission line, the shunt capacitance is usually neglected because its effect is minimal compared to the line's inductance and resistance.
Shunt capacitance is the capacitance between the conductors and the ground, which can cause the line to behave like a low-pass filter, passing low-frequency signals and attenuating high-frequency signals.
For short transmission lines, the length of the line is usually less than 80 km, and the voltage level is relatively low, typically below 69 kV.
At these low voltage levels and short line lengths, the effect of shunt capacitance is negligible, and the line can be modeled as a lumped parameter circuit with only series resistance, inductance, and capacitance.