Modelling of corona at a high-voltage conductor under double exponential and oscillatory impulses

An alternating-current corona model is adapted to allow its application to fast transient overvoltages in coaxial geometries. An initial study of data for positive and negative lightning and switching impulses shows good agreement between the model and experiment. Application is then made to a negative corona under oscillatory impulses with frequencies of 33 and 125kHz. The model is used to aid interpretation of the complex experimental results, and gain an insight into the underlying physical phenomena. A semi-quantitative adaptation is then made to successfully simulate experimental data. The model is shown to be applicable to all voltage types including direct, alternating and impulse voltages.