THE SUBSTANTIAL MECHANISMS OF STEP VOLTAGE EFFECTS
Nobuichiro Kitagawa, Masaharu Ohashi, Tsuyoshi Ishikawa · Journal of Atmospheric Electricity · 2001
The injuries caused by the potential difference on the ground surface due to the ground flash are called step voltage injuries.The authors have examined the injuries of this category, based on the numerous field investigations of human lightning accidents.It is found that two different mechanisms of current flow along the ground surface are associated with the ground flash.When a lightning flash reaches the ground, the lightning current usually flows through the upper layer of the ground as conduction current.If a person contacts the ground with plural parts of his body, he is subjected to the potential difference between those two parts but the effects he receives are temporary and slight.Sometimes, when a lightning flash reaches the ground, a surface arc discharge develops along the ground surface together with the flow of the conduction current in the ground.If a person is situated on this discharge path, he receives severe effects.He suffers thermal injuries and paralysis, he may lose his walking ability and may be killed in worst case.To compile the safety guide against lighting hazards, these two different mechanisms of current flow along the ground surface due to the ground flash should be considered.