Numerical Simulation of V-q Characteristics of Impulsive Corona for Thin Conductor in Coaxial Corona Cage

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
$100\mu\mathrm{S}/\mathrm{m}$
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.