Abridgment of the effect of transient voltages on dielectrics — IV: Law of impulse spark-over and time lag: Relative effects of different wave shapes — Comparison of lightning waves and laboratory waves — Coordination of line insulation

It is the object of this paper to discuss the relative effects of different forms of voltage transients on insulators, gaps, and insulation; to show how the effects and breakdown voltages of various types of transients are related; and to compare natural lightning waves with those used in the laboratory. Such knowledge is necessary in making a comparison of insulators, insulation, and in coordination. The law of impulse sparkover has been determined and formulas have been developed to predetermine time lag and breakdown voltage for the various types of transients.