In order to calculate the lightning overvoltage waveform and propagation process considering the impulse corona effect, based on Finite Difference Time Domain (FDTD) and streamer discharge theory, a method is proposed to determine the corona area dynamically, and a thin conductor corona calculation model that can consider the effect of inhomogeneous electric field on corona and corona dynamic process is established. The study of V-q characteristics of the coaxial corona cage system was carried out to verify the accuracy of the model. The influence of the corona conductivity on the V-q characteristics was analyzed, and it was concluded that the conductivity of 100μS/m under positive polarity corona is in good agreement with the experimental results in the literature. The effect of the measurement capacitor on the V-q characteristics is also analyzed, and it is concluded that the V-q characteristics measured by a corona cage under a particular condition cannot be extrapolated to a real transmission line. The work in this paper can provide a reference for lightning overvoltage simulation calculations considering the impulse corona effect and V-q characteristic measurement tests using corona cages.

impulse corona；finite difference time domain method；q-V curve；lightning transient calculation