| Power loss caused by lightning protection reasons is deeply studied in this thesis, a method of calculating electromagnetic and electrostatic induced voltage as well as the components of power loss is summed up. The calculation of circulation current is improved by utilizing the theory of flux in multi-conductor lines, making power loss calculation more precisely. The influencing factors and measurements for reducing power loss in lightning shield line are analyzed, an ATP simulated calculation model is built-up to analyze the feasibility of multiple impendence, and the results indicates that this method can certainly reduce the inductive current in lightning line.Considering the heterogeneity of the soil, a multi-layer horizontal soil model is built in order to calculate the power loss accurately in lightning-shield line. Based on Maxwell's equations, the formulas of equivalent width for the electromagnetic field are deduced, this article also puts forward a way of the calculation for impedance in the lightning-shield line when considering the two-layer horizontal soil. Finally grounding resistance and soil resistivity are measured under the condition of two-layer horizontal soil, and the model is proved to be reasonable. |
