# What is Skin Effect | Reduce Skin Effect in Transmission Lines

## What is Skin Effect:

The tendency of the alternating current to concentrate near the surface of a conductor is called skin effect. The direct current distribution in a conductor is uniform. But the alternating current distribution in a conductor is not uniform. The current density near the surface is more than near to the center of the conductor which means the current flow in the surface of the conductor is higher than the current flow in the center of the conductor. It is affected by the frequency of the current. If the frequency of the current is more the current distribution is more non-uniform. This effect is called as skin effect. The effective cross sectional area of the conductor through which current flows is reduce.

Let’s we take a conductor in solid state and bundled conductor.

In that R is the resistance of the solid conductor and I is the current through the conductor. N is the number of strands, nR is the resistance of each strand and the current through each strand is I/n..

Let assume half of the conductor n/2 carry the currents of Here you can see that the effective resistance of alternating current is more than the direct current. oif the current distribution is not uniform.

At the same time, the inductance of each strand will be varied according to its position. The strand near the center are surrounded by a greater magnetic flux hence we get larger inductance. The flux linking the strand decreases as we move towards the outer strand. Therefore, the outside strand conduct more current than inside strand. Also the skin effect is purely depending upon the resistivity, frequency, conductor size and permeability of the conductor.

Note: The skin effect is negligible for the system frequency is less than 50 Hz and the conductor diameter is less than 1 cm.