Kalman filter algorithm for digitally recorded lightning impulse parameter evaluation

Relevant standards establish the construction of a mean curve in lightning impulses with perturbations (oscillations, overshoot, noise) in order to determine impulse characteristic parameters (peak value, front time, time to half-value and voltage at the instant of chopping and time to chopping if it is the case). A new method for constructing a mean curve in lightning impulses that uses an extended Kalman filter is described. This method needs a model for the mean curve or smooth impulse. A smooth impulse model based on existing ones is adopted. Results obtained with mathematical and real impulses are presented.