Thesis (M.Eng.)--Chulalongkorn University, 2010

Lightning is one of the most destructive natural phenomena that we know. It occurs frequently in tropical countries, such as Vietnam and Thailand. Thus, the air insulated substations, which is an important asset in the electric power transmission, are prone to be struck by lightning. The consequences are: physical, economic, and sometimes life damages. However, the damages may be reduced by using a suitable lightning protection system, LPS. But, the design of an LPS of large substation by using masts is very difficult, especially if we use hand-calculation. This thesis proposes a software tool to design an LPS for a substation by using mast. The model in use is the most currently acceptable one, i.e. electrogeometric model. Users can select various striking distances in the design, e.g. from Love, Young, CIGRE, or IEEE equations. The criteria for the selection of an appropriate kind of striking distance equations in the design of an LPS of a substation are also discussed.