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Journal of the Korean Institute of Illuminating and Electrical Installation Engineers

ISO Journal TitleJ Korean Inst. IIIum. Electr. Install. Eng.
Title Grounding Impedance Behaviors Associated with the Current Injection Point and the Length of Counterpoise
Authors Feng Li ; Bok-Hee Lee
Page pp.66-71
ISSN 1225-1135
Keywords Transient Grounding Impedance ; Impulse Current ; Soil Resistivity ; Counterpoise ; Conventional Grounding Impedance
Abstract This paper presents the grounding impedance behaviors of counterpoise exposed to impulse currents. The transient and conventional grounding impedances of three counterpoises having the length of 10, 30 and 50 [m] were measured and analyzed as a function of the injection point of impulse currents. As a result, the trend of the conventional grounding impedances measured as a function of risetime of impulse current is similar to the transient grounding impedance of counterpoise. The injection point of impulse current has great influence on the transient grounding impedance characteristics of counterpoise. The transient grounding impedance characteristics in a short time range are strongly dependent on the length of counterpoise. The transient characteristics of grounding impedance of 10 [m] counterpoise subjected to the impulse current was capacitive behavior, on the other hand, those of 30 [m] and 50 [m] counterpoises were inductive behavior. It is found that the grounding conductor should be connected to the central point of counterpoise.