抄録
The authors measured lightning overvoltages in railway level crossing systems representing typical examples of wayside electronic signalling equipment at the field. This measurement was carried out to analyze quantitatively the frequency of lightning overvoltage occurrence and to collect basic data for countermeasures against lightning. As a result, an experimental equation to estimate the occurrence frequency of lightning overvoltages in the level crossing system was derived. This equation can estimate the occurrence probability of lightning damages caused by exceeding the withstand voltage of the level crossing system. Moreover, this equation is useful to evaluate the rate of reduction in lightning damages against the level of lightning protection. For example, if the level of lightning protection can be improved from 10kV to 30kV, it is calculated that the occurrence probability of lightning damages will be reduced to 1/10 or less according to the equation.
