Switching and Lightning Impulse Discharge Characteristics of Large Air Gaps and Long Insulator Strings

Analysis of the influence of electrode shapes on the behavior of air gaps, both with and without insulator strings between the electrodes, is completed through the use of switching impulse tests. Results of a similar analysis for lightning impulse tests are also described. An attempt is made to correlate the behavior of air gaps in switching and lightning impulse tests to a factor k which characterizes the shape of the electrodes. Diagrams are given that express discharge voltages for switching and lightning impulse tests as a function of k.