대형 봉상 접지전극의 접지임피던스와 주파수 응답특성

초록

In order to analyze the dynamic characteristics of ground impedance in large grounding system for lightning and surge protections, a novel method for measuring the ground impedance as a function of frequency was proposed. The experiments were carried out in the grounding system composed of ground rods and mesh grids . The test current was injected by the variable frequency inverter whose frequency is linearly controlled in the range of 5 ~ 500㎑. The ground impedance and frequency reponse of the grounding system were mainly caused by the inductive current flowing through grounding conductors over the frequency of 20㎑. In the combined grounding system of rods and mesh grids, inductive component of ground impedance was significantly decreased. It was turned out that the grounding system is effective for the surge protection.