Characterization of the lightning wave

From Electrical Installation Guide

Analysis of the phenomena allows definition of the types of lightning current and voltage waves.

  • 2 types of current wave are considered by the IEC standards:
  • 10/350 µs wave: to characterize the current waves from a direct lightning stroke (see Fig. J9);
Fig. J9 – 10/350 µs current wave
  • 8/20 µs wave: to characterize the current waves from an indirect lightning stroke (see Fig. J10).
Fig. J10 – 8/20 µs current wave

These two types of lightning current wave are used to define tests on SPDs (IEC standard 61643-11) and equipment immunity to lightning currents.

The peak value of the current wave characterizes the intensity of the lightning stroke.

  • The overvoltages created by lightning strokes are characterized by a 1.2/50 µs voltage wave (see Fig. J11).

This type of voltage wave is used to verify equipment's withstand to overvoltages of atmospheric origin (impulse voltage as per IEC 61000-4-5).

Fig. J11 – 1.2/50 µs voltage wave