The insulating material around the conductor forms a dielectric medium around a conductor. So, a conductor which is electrically energized when encapsulated inside insulation becomes a device much familiar like a capacitor. In a capacitor, the inner portion contains electrodes and are electrically energized during the flow of current but its outer layer is completed composed of the dielectric medium. The dielectric medium is also composed of some losses when it comes to absorbing the dissipating electromagnetic energy. These dielectric losses in the cable could be found by using the loss angle δ or the corresponding tangent of loss angle tan δ.
The dielectric medium itself contain positive and negative charges which are bounded together. Dielectric medium is actually an insulator but it gets affected by an electric field. All the concentration of a charge is inside at the center of the charge, either it could be positive or negative. So, the point at which the whole concentration of the charge lies is its center of gravity of the charge.
These Dielectric are further divided into two types:
1) Polar Dielectric
Polar Dielectric is that type in which there is zero possibility of the collision of the centers of positive and negative charges. In a polar dielectric, the charges never coincide with each other. The reason behind this is their asymmetrical shape and size.
2) Non-Polar Dielectric losses
Non- Polar Dielectric is that type in which there is a possibility of the collision of the centers of positive and negative charges. In a non-polar dielectric, the charges always coincide with each other. The reason behind this is their symmetrical shape and size.
The dielectric insulating material is highly prone to dielectric losses because of the dielectric heating. At higher frequency electric field the electromagnetic nature of the conductor heats the dielectric material.