Computation and measurement of AC electric and magnetic field lateral profiles and longitudinal contours under transmission lines

EHV and UHV AC transmission lines and electrical equipment produce electric and magnetic fields around their vicinity. AC conductors used for 220 kV and below are usually designed on the basis of current carrying capacity, whereas those for 400 kV and above have to take into account the electromagnetic fields produced by them. The design of EHV and UHV lines should also consider the consequences of the fields on objects and human beings when their levels are beyond certain limits. Because of this, it is necessary to be able to estimate these electromagnetic fields through computations. A program has been developed for computing the electric and magnetic fields around the transmission lines in India. The computed and the measured values of these fields are presented in this paper for the existing lines in Indian systems.