가변주파수 인버터를 이용한 접지임피던스의 새로운 측정기법

초록

A novel method for measuring the ground impedance as a function of frequency were experimentally investigated. The experiments were carried out in rectangular grounding grids with 6×8 conductors of 22 ㎟ buried at a depth of 0.5m. The test current was injected by the variable frequency inverter whose frequency is linearly controlled in the range of 5 ~ 500 ㎑. The amplitude and phase of ground impedance were calculated from the waveforms of the test current and ground potential rise measure by the band-pass filter tuned in a specific impedance was mainly caused by the inductive ground flowing through grounding conductors over the frequency of 100 ㎑.