Corona Modelling for the Calculation of Transients on Transmission Lines

The paper presents a mathematical corona model and its use for transmission line modelling with corona and, if desired, with frequency dependence of its parameters. The corona model has been developed from macroscopical physical laws, reflecting relations between charge, electric field intensity and voltage. Space charges, their development and their displacement are taken into account. The parameters of the model are determined so that the simulated qv curves closely fit those available from measurements. The corona model is then used as an element of the discretized transmission line model. This consists either of longitudinal inductances or of travel delay modules. Modelling of frequency dependence is optional. The line equations are integrated using the trapezoidal rule, so that Norton equivalents are obtained for the two line ends for the purpose of interfacing with the external system. Thus the model is fully compatible with an Electro-Magnetic Transients Program (EMTP).