Frequency Dependent Grounding Impedance As a Function of Soil Resistivity

대지저항률에 따른 접지임피던스의 주파수 의존성

A design criterion of grounding systems is commonly based on low frequency resistance in Korea. When lightning surges which have high frequency components are injected into the grounding system, the grounding impedance is greatly different from the static grounding resistance. This paper presents the grounding adimittance and phase on the frequency range from 100 [Hz] to 15 [MHz] using water tank simulating the grounding system in different water resistivities. As a result, capacitive effect is dominant over the frequency of 100 [kHz] at the water resistivity of 1,000 [$\Omega$ m]. On the other hand, the inductive characteristics appear at the low water resistivity. Consequently, dependence of grounding impedances on the frequency of injected current is strongly related to resistivity.