Lightning-induced surges in building electrical systems

2014 International Conference on Lightning Protection, ICLP 2014, Shanghai, 11-18 October 2014This paper presents a numerical investigation into lightning induced surges using a FDTD method. When the down conductor in a building discharges a lightning current, substantial induced voltages are observed in the adjacent distribution circuits. The induced surge voltage is linearly proportional to wave-front parameters of the lightning discharge current, and is a logarithmic function of the distance ratio of two circuit conductors. It is found that capacitances can suppress the induced surge voltage substantially. SPDs are recommended to install at two far ends of a distribution circuit. They do not need to dissipate substantial lightning surge energy observed in the down conductor. It is also found that the surge currents in SPDs are similar to those in short circuits, and can be estimated by using a low-frequency formula.Department of Building Services EngineeringRefereed conference pape