Protection scheme and reliability assessment of ICC box for FAA Approach Lighting System against lightning strikes

The Approach Lighting System in use by Federal Aviation Administration has over the years been subjected to lightning affects that results in breakdown of an the Individual Control Cabinet (ICC box). Previous work has investigated to what extent lightning surge effect could have on the ICC box. This work had resulted in the configurations of the ALS as topologies I, II and III. Of the three topologies, experimental test carried out shows that topology II results in optimal configuration. Hence, this topology is carefully evaluated in this paper with a view to provide a protection circuitry that will mitigate the lightning surge effect on the ICC box. Critical evaluation of this protection circuitry proves that a metal-oxide varistor and metal-oxide-semiconductor field-effect-transistor (MOSFET) are the basic protective device elements. These devices when incorporated in topology II results in the mitigation of the ICC box breakdown against lightning strikes.