Parameters of lightning stroke currents defining their mechanical and thermal effects

Mechanical and thermal effects of lightning strokes depend on values of the impulse charge and specific energy of a lightning discharge current. For typical lightning currents and different lightning protection levels (LPL) as defined in IEC Std. 62305 these values can be calculated as the integral of channelbase current function and integral of the square of that function. The results presented in this paper for the new channel-base current function (NCBC) are in good agreement with experimentally measured values of these quantities. This function is used for approximating lightning channel-base currents and it provides a very simple calculation procedure. Values of the impulse charge and specific energy are useful for estimating reliability of some lightning protection structure and its parts for the defined LPL.