EXPERIMENTAL STUDY OF EMISSION CURRENT FROM LIGHTNING PROTECTION DEVICES UNDER RAIN AND WIND CONDITIONS

The experimental study of emission current from the lightning protection devices is presented. Emission currents were measured using switching impulse voltage. A metal screen was used to provide simulation of a charged cloud. Measurements of emission current from a Franklin Rod and three configurations of static dissipation devices were conducted in the high voltage laboratory under different environmental conditions. The measurements of emission current were conducted for: no rain or wind, with low and high wind, and with light and heavy rain. The generated switching impulse in this test had a time-to- peak of 250 �s and a time-to-half-value of 2000 �s, both positive and negative polarity. Measurements were taken at 3 m and 4 m air gap spacing from the metal screen to the test device. The presented emission current is averaged from three measurements for the same voltage magnitude and polarity of the applied impulse. For each of the three devices, four different levels of voltages were applied from 800 kV to 1100 kV at positive and negative polarity. From the conducted study of the emission current of four lightning protection devices, several conclusions were stated. The study shows emission current is highest for the heavy rain condition. The applied wind speeds up to 2 m/s did not have an impact on emission current. The Franklin Rod showed the lowest measured emission current for all study cases.