Analytical Studies On Lightning Surge Response Simulation Of Transmission Tower By FDTD

In the field of lightning protection, it has always been pursued to accurately simulatethe lightning response of the tower. It has been shown that comparing with the simulationresult based on EMTP, the simulation result of lightning response of tower is more accurate.Therefore, this paper chose the FDTD method to simulate the lightning surge response oftower.Firstly, the basic principles and key technologies about FDTD were introduced in thispaper. In addition to the original contents of the book, some important contents areelaborated. These contents include differential form of Liao’s absorbing boundary condition,one new method to equivalent current source and the method to simulate thin wire based onthe quasi-static field theory.To achieve the simulation of the transient response of lightning towers, this paperintroduced the modeling approach of lightning channel, ground wire, bundled conductorsand transmission tower. Through comparison with three examples, the validity andaccuracy of the modeling approach was verified.The lightning surge response of the wineglass tower, double-circuit transmission towerand quadruple-circuit transmission tower was simulated by the FDTD method. Thesimulation results show that when the amplitude of the lightning current is1A, for thewineglass tower with the height of50m, the overvoltage between phase line and towerranges from19.9to23.1V and the peak time ranges from0.817to0.998μs. For thedouble-circuit transmission tower with the height of89.5m, the overvoltage between phaseline and tower ranges from21.9to29.1V and the peak time ranges from1.12to1.3μs. Forthe quadruple-circuit transmission tower with the height of79.9m, the overvoltage betweenphase line and tower ranges from14.4to33V and the peak time ranges from1.15to1.35μs.Lastly, according to the simulation results of FDTD, the characteristic impedances ofthe wineglass tower, double-circuit transmission tower and quadruple-circuit transmissiontower are determined. Based on the characteristic impedance, the simulation results of thelightning surge response of the wineglass tower, double-circuit transmission tower andquadruple-circuit transmission tower are relatively close to the simulation results by theFDTD method.