You all know about what is skin? yes, you guess the right … but we are here not concerned about skin of the human body.
Here, we will talk about skin of the conductor of an electrical transmission line …
You have seen the transmission line. a transmission line is made up of towers, conductors and insulators.
Generally Alternating current (AC) flows through these conductors. When this current flows through the conductor. it flows through skin of the conductor or outer surface of the conductor … and no current flows through the center portion of the conductor. it means AC current distribution over the conductor is non-uniform.
This non-uniform distribution of AC current or current flowing only through skin of the conductor is called skin effect.
Kindly note that there is no Skin effect when DC current flows through the conductor So, if someone ask you than tell him that there is no skin effect in case of DC and Skin effect only happens in case of AC.
Reasons of the skin effect: Inductance or inductive reactance
The central portion of the conductor has maximum inductance or reactance and as we move away from the center of the conductor, it reduces and becomes very least on the outer surface or skin of the conductor.
You all know that current flows through least resistance path that’s why AC current flows through skin or outer surface of the conductor.
In case of, there is no inductance or no inductive reactance, so there is no skin effect in DC and current equally distributed over the conductor.
Skin effect depends on the following parameters.
- Nature of the material
- Diameter of the wire: Skin effect increases with conductor diameter.
- Frequency: Skin effect increases with increase in frequency,
- Shape of the conductor: Less for standard conductor and more for solid conductor
- Distance between conductors
- Resistivity of the material
- permeability of the material