Impulse Response Characteristics of the Grounding Systems with respect to the Common-Connection Position in Power Utility System

수변전설비에서 접지시스템의 공결점의 위치에 따른 임펄스 응답특성

This paper describes the impulse response characteristics of the grounding systems in power utility system. Several regulations regarding to electric power equipments, services and managements require that the groundings of class 1 ($E_1$) and class 2 ($E_2$) must be connected at the common point in grounding systems. In addition, the grounding for arrester ($E_{LA}$), which belongs to the grounding of class 1, should be connected at the same point. However, there is no method and position of common-connection at anywhere. In this work, when the impulse current was injected through the grounding conductor for arrester, the investigations measuring and analyzing potential rises induced at the common connection point and other grounding conductors were conducted. The experiments were carried out in the conditions of the grounding conductor of 25m long and the near or remote common connection from ground electrode. The lightning impulse current was applied so as to simulate the on-set of arrester due to lightning and/or switching surges.