Double-Exponential Parameter Determination for the Lightning Impulse Voltage

Abstract

This paper proposes approximation functions which give the double-exponential function parameters for the given lightning impulse voltage. The functions are derived from the normalised lightning impulse voltage where the double-exponential function is scaled in the time direction so that the number of parameter presenting the function is reduced from two to one, making then treatment of the function much easier. Using the proposed approximation function, one can compute the double-exponential function parameters as precise as 0.03% an error negligible even with a 12bit-recording device. Also in the paper, the Newton method for solving a set of simultaneous non-linear equations quite precisely is discussed.