Discharge Process Observation and Experiment of the Influence of the Grounding Resistance on Triggered Lightning Abilities of High Tower

Abstract

In order to study the relationship between the triggering lightning ability of a triggering lightning tower with grounding resistance, numerous discharge experiments with standard switching impulse were conducted on the triggering lightning tower which was scaled with a ratio of 1:12.5, and the high tower was connected to the test grounding system through 10 Ω and 100 Ω resistors. An up-and-down method was adopted for 50% discharge voltage. The discharge process was observed by a high-speed camera. The experimental results show that the grounding resistance is negatively correlated with the triggering lighting ability, namely, the triggering lightning ability of a high tower is stronger when the grounding resistance is lower. At the same spatial scale, the difference value of H, which is the ratio of the upward and downward leader, is increased with test gap distance, and the variation range of the difference ΔH is 0.59%~3.29%. In the double-tower selective discharge tests, the high tower connected with 100 Ω grounding resistance in tstr and tn rises by 3.34% and 4.71% compared to that connected with 10 Ω, respectively. Thus the experimental results reveal that the triggering lightning ability will be influenced by the grounding performance of triggering lighting tower, and the triggering lightning ability of high tower will be enhanced by reducing the grounding resistance appropriately.