Skin effect and proximity effect

When an ac current is flowing through a good quality conductor, current distribution follows a non-uniform pattern. Inner portion of the conductor has more flux linkage than outer portion. Because of this fact, we can conclude that the inductive reactance in the inner portion of the conductor more than the outer surface of the conductor. Now the effective current in the outer surface of the conductor will be more than the inner surface, thus reducing effective cross-section of the conductor. This increases the effective resistance of the conductor. This is called skin effect. Skin effect is good and blessing for ACSR conductor. In ACSR conductor, inner steel reinforced conductor does not effectively carry any current and this helps to avoid the higher resistivity of steel compared to copper. Loss of power will be more if skin effect exists. Proximity effect is the effect of non-uniform distribution of current of a conductor due to the effect of flux linkage from a neighboring conductor.