If the effect of earth is taken into account, then the capacitance of line to ground:

Effect of Earth on Capacitance of Transmission Line:

In Transmission Line, two types of capacitance exist:

The first one is the capacitance between the phase conductors and the second one is shunt capacitance between the conductor and the earth.

The capacitance between the phase conductors is not only dependent on conductor spacing, the radius of conductor, and height of conductor from the ground rather it is also influenced by the earth.

As we know that the capacitance of a single-phase transmission line is given as

\({\large{\bf{c}} = \frac{{{\bf{\pi }}{{\bf{\varepsilon }}_0}}}{{\ln \left( {\frac{{\bf{D}}}{{\bf{r}}}} \right)\;}}}\)

Where D = Separation between the go and Return conductor

r = Radius of conductor

From the above value of capacitance, we observe that the capacitance is inversely proportional to the distance (D) hence capacitance of the conductor has increased due to the effect of Earth.