Impulse Characteristics of Model Grounding Electrodes for a Transmission Tower-Footing Base Structure

The analysis of dynamic behavior of the transmission tower-footing base structure subjected to lightning currents is very important for the insulation design of transmission lines. We conducted a model experiment to propose a technique to investigate the dynamic characteristics of the ground resistance and the impulse response characteristics of the transmission tower-footing structure when soil ionization occurs due to the high surge current injected into the grounding electrode. The impulse characteristics of the ground resistance were measured and analyzed by using a hemispherical grounding electrode and a scale-down model grounding electrode of the transmission tower-footing base structure. Based on the model experiment using a scaling rule, we propose a method to estimate the impulse response of the actual transmission tower-footing structure.