Frequency-dependent Impedance Characteristics of a Grounding Grid

초록

The grounding system performance analysis based on high frequency currents is required in order to design the grounding systems for lightning protection systems. The purpose of this research is analyzing the frequency-dependent impedance characteristics of grounding grids. In this paper, the experimental measurements and the simulation of the frequency-dependent grounding impedance and ground current dissipations at each section of the 10 m×10 m square grounding grid were investigated. The grounding impedance and the ground current dissipation are measured and analyzed as a function of the test current injection point. When the test current injected at the center of the grounding grid, the grounding impedances are lower than those measured on the corner or side of the grounding grid. The simulation results of grounding impedance and ground current dissipation rates calculated via the non-uniform distributed parameter circuit model are in good agreement with the data measured at the test site. Therefore, the results obtained from this work can be used in design of high frequency grounding systems for lightning and switching surge protection.