Digitally recorded lightning impulse with overshoot parameter evaluation by using the Kalman filtering method

Relevant standards establish the construction of a mean curve in lightning impulses with perturbations (oscillations, overshoot, noise) in order to determine the 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). In the case of an impulse with overshoot the guidance given by the IEC 60-1 standard in order to determine the existence of overshoot, the duration of overshoot and the mean curve to be drawn are not sufficient if digital recording systems are used. This problem is studied and a procedure that uses the Kalman filtering method in conjunction with acceptable criteria is described. Results obtained with analytical impulses, real impulses and the reference waveforms of the IEC 1083-2 standard are presented. Suggestions to improve the actual standards are given.