Corona characteristics under lightning surges

An analysis is made for the attenuation and distortion of lightning surges traveling on overhead transmission lines under the corona condition. The corona characteristics are described by the q-u curves. The parameters of the surge waveshapes are varied experimentally to examine their effects on the q-u curves. A discussion about the experimental data is presented with emphasis on the corona onset voltage gradient, dynamic capacitance of the line conductor and energy losses of corona. It provides the foundation for accurate calculation of lightning overvoltages.