The energy losses that happen in case of transmission lines are shown below:
1. Conductor Heating
2. Dielectric heating
3. Radiation Losses
It is observed that the radiation loss in parallel wire lines is much more than that of the coaxial cables.
Conductor heating: The heating rate of a conductor is directly proportional to the square of the current. It is inversely proportional to the characteristic impedance (Zo). Conductor heating will also increase with the increase in frequency.
Radiation Loss: The transmission lines act as antennas when the separation distance between the conductors is very small as compared to their wavelength. Then the conductor starts radiating energy. As we will increase the frequency the radiation loss will also increase.
Dielectric heating: It directly depends upon the voltage flowing across the dielectric. Similar to conductor heating, it is also inversely proportional to the characteristic impedance of the line. In this case the loss also increases with the increase in frequency. If we use air as the dielectric medium then the loss will be almost zero.
