Analysis and test on electric field concentration effect of bipolar conventional air terminal

In this paper, we present that the bipolar conventional air terminal (BCAT) with a floating conductor affects the electric field distribution. When the thunderstorm clouds approach facilities placed on the top of buildings, electric field is intensified around facilities. So, the probability of lightning strikes increases. The BCAT is used to protect the facilities because it alleviates the electric field near them. The mechanism of a floating conductor discharge is explained, and the analysis models according to existence of BCAT are analyzed using finite element method. The object to be protected from lightning is placed between BCATs. In this experiment, the flashover voltage is measured when the flashover occurs at the analysis models by increasing DC high voltage simulating thundercloud. These flashover voltages of each model are measured and compared with each other. As a result, it was found that flashover voltage is reduced by 10% in the condition with BCAT in comparison with the condition without it. This paper reviews the electric field reduction of BCAT. Future study and research are to carry out the electric field analysis and experiment in various conditions with different allocation of structures and the lightning rod and in the condition which flashover does not occur.