On Attempts to Protect a Structure from Lightning Strikes by Enhanced Space Charge Generation

ABSTRACT

Research conducted in laboratory on long sparks shows that the breakdown voltage of spark gaps increases the presence of corona emission from one or both of the electrodes. This observation together with other reasoning based on intuition has led some scientists to suggest the possibility of avoiding a lightning strike to a building by introducing sufficient quantities of space charge around it. In this paper the way in which the striking distance of a slim structure changes as a result of it being equipped with a network of corona generating needles is investigated. Based on the results presented in this paper one can make the following conclusions. (a) The connection of a corona element of radius Rc on top of a tower of radius R ( Rc> R ) will lead to a decrease in the striking distance of the tower. This decrease is purely a geometrical effect and the space charge generated by the corona needles may play only a minor role in reducing the striking distance. (b) Neither the geometrical effect nor the space charge generated by the corona element can reduce the striking distance of a given tower below a certain critical value which depends only on the charge on the stepped leader. Thus, the corona element will not be able to prevent a lightning flash terminating on the tower.

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