• 제목/요약/키워드: Grounding point

검색결과 97건 처리시간 0.024초

대규모 그리드 접지전극의 과도접지임피던스의 측정 (The transient grounding impedance measurment of large grid grounding electrodes)

  • 전병욱;이수봉;이봉;이승주;정동철;이복희
    • 한국조명전기설비학회:학술대회논문집
    • /
    • 한국조명전기설비학회 2008년도 추계학술대회 논문집
    • /
    • pp.69-72
    • /
    • 2008
  • This paper presents the transient and conventional grounding impedance behaviors of large grid grounding system associated with the injection point of impulse current The measurement methods consider two possible errors in the grounding-system impedances: (1) ground mutual resistance due to current flow through ground from the ground electrode to be measured to the current auxiliary, (2) ac mutual coupling between the current test lead and the potential test lead The test circuit was set to reduce the error factors. The transient grounding impedance depends on the rise time and injection point of impulse current It is effective that grounding conductor is connected to the center of the large grid grounding system.

  • PDF

배전계통에 사용되는 봉형 접지전극의 접지 특성 분석 (Grounding Characteristics Analysis of the Rod-Type Grounding Electrodes used for Electric Distribution Systems)

  • 김경철;정지원
    • 조명전기설비학회논문지
    • /
    • 제25권6호
    • /
    • pp.49-56
    • /
    • 2011
  • Grounding system insures a reference potential point for electric devices and also provides a low impedance path for fault currents or transient currents in the earth. The ground impedance as function of frequency is necessary for determining its performance since fault currents could contain a wide range of frequencies. In this paper, the grounding resistance, grounding impedance and transient grounding impedance are measured by using 3-point fall-of-potential method in order to analyse grounding characteristics of the copper and concrete rod grounding electrodes. An equivalent transfer function model of the ground impedance and transient grounding impedance are identified from the measured values by using ARMA method and evaluated by comparing the conventional grounding impedance.

A Study on Lightning Overvoltage Characteristics of Grounding Systems in Underground Distribution Power Cables

  • Jung, Chae-Kyun;Jung, Yeon-Ha;Kang, Ji-Won
    • Journal of Electrical Engineering and Technology
    • /
    • 제9권2호
    • /
    • pp.628-634
    • /
    • 2014
  • This paper investigates the transient characteristics of grounding systems used in under-ground distribution power cables. Recently, two kinds of grounding system are used for underground distribution cables in Korea. The first one is conventional multi-point grounding system, the other is newly proposed non-bundled common grounding system. The non-bundled common grounding system has an advantage the decreasing the power loss due to decrease of the shield circulation current. In this paper, the lightning overvoltage induced in neutral wire (in case of non-bundled common grounding system, overvoltage between opened neural wires and grounding in each phase) of these two kinds of grounding systems are estimated and compared by field tests and EMTP simulations. The EMTP simulation methods are firstly verified by comparison of measurement and simulation. Finally, the insulation level against lightning is expected by EMTP simulation results using verified model.

배전전주용 스테인리스강판 접지전극의 접지 특성분석 (Grounding Characteristics Analysis of the Stainless-steel Plate Grounding Electrode for Distribution Poles)

  • 김경철;이규진;김민성;정지원
    • 조명전기설비학회논문지
    • /
    • 제24권8호
    • /
    • pp.94-100
    • /
    • 2010
  • 접지시스템은 전기설비의 기준 전위점을 확보할뿐만 아니라 낮은 대지저항으로 고장전류나 과도 전류를 흐르게 한다. 접지임피던스는 주파수에 대한 함수로 고장이나 과도전류가 넓은 범위의 주파수 성분을 포함하기 때문에 접지성능을 평가하는데 중요한 역할을 한다. 본 논문에서는 스테인리스강판 접지전극의 접지특성을 파악하기 위하여 3점 전위강하법으로 접지저항, 접지임피던스와 과도접지임피던스를 측정하였다. 측정된 데이터를 이용하여 접지임피던스와 과도접지임피던스의 등가 전달함수 모델은 ARMA 기법으로 모델링 되었고, 규약접지임피던스로 비교하여 평가하였다.

매설지선의 길이와 전류인가점에 따른 접지임피던스특성 (Grounding Impedance Behaviors Associated with the Current Injection Point and the Length of Counterpoise)

  • 이봉;이복희
    • 조명전기설비학회논문지
    • /
    • 제23권6호
    • /
    • pp.66-71
    • /
    • 2009
  • 본 논문은 임펄스전류가 인가된 매설지선의 과도접지임피던스특성에 관한 것으로 길이가 10, 30, 50 [m]인 3개의 매설지선에 대하여 입 펄스전류의 인가점을 파라미터로 하여 과도접지임피던스와 규약접지임피던스를 측정하고 분석하였다. 임펄스전류의 상승시간에 대한 규약접지임피던스는 과도접지임피던스와 비슷한 경향이었다. 과도접지임피던스는 임 펄스전류의 인가위치에 영향을 크게 밭으며, 짧은 시간영역에서 과도접지임피던스는 매설지선의 길이에 매우 의존적이다. 임펄스전류가 인가된 10[m]의 매설지선은 용량성 특성이었으나 30[m]와 50[m]의 매설지선은 유도성 특성을 나타내었다. 접지도선은 매설지선의 중앙점에 접속하는 것이 바람직한 것으로 밝혀졌다.

일점접지방식을 이용한 전자교환기 방호의 실제 (Engineering Practice for ESS Protection by means of One Point Grounding System)

  • 김수형;서정욱
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
    • /
    • pp.502-505
    • /
    • 1988
  • This paper is to demonstrate the effectiveness of one point grounding in support of ESS protection. One point grounding provides for the dispatching of excess energy for protection of switching equipment and personnel from lightning discharge hazards and for a natural sink for noise from atmospheric lightning and power transients. In most ESS installations there are a number of different items that must be maintained at a common ground potential for safety, fault protection or noise reduction. The items typically consist of power systems, heating and ventilating systems, distributing frames, repeating equipmets, switching equipments, etc. Grounding system of an ESS Office is most effective when all the ground points are connected to a single, common earth. The one point grounding prvides a common reference potential, keeping all the items of telecommunications facility free from the earth current and voltage hazards.

  • PDF

수변전설비에서 접지시스템의 공결점의 위치에 따른 임펄스 응답특성 (Impulse Response Characteristics of the Grounding Systems with respect to the Common-Connection Position in Power Utility System)

  • 이복희;엄주홍;김성원;심판섭;이승칠
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 1999년도 하계학술대회 논문집 E
    • /
    • pp.2149-2151
    • /
    • 1999
  • 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.

  • PDF

임펄스전류의 인가위치에 따른 심매실 봉상 접지전극의 과도접지임피던스 특선 (Transient Grounding Impedance Behaviors of Deeply-driven Ground Rods According to the Injection Point of Impulse Currents)

  • 이수봉;이봉;이승주;전병욱;이복희
    • 조명전기설비학회논문지
    • /
    • 제22권10호
    • /
    • pp.62-68
    • /
    • 2008
  • 본 논문은 임펄스전류의 인가위치에 따른 심매설 봉상 접지전극의 과도접지임피던스와 규약접지임피던스 특성에 관하여 기술하였다. 과도접지임피던스는 심매설 접지전극의 길이 및 임펄스전류의 상승시간과 인가위치에 강하게 의존하며, 접지전극의 자체 인덕턴스는 짧은 시간 영역에서 점지시스템의 과도접지임피던스에 크게 영향을 미치는 것으로 나타났다. 심매설 봉상 접지전극의 자체 인덕턴스의 저감은 과도접지임피던스 특성의 개선에 결정적인 역할을 한다. 접지도선의 길이는 최대한 짧게 하여 접지전극의 상단에 접속하는 것이 효과적이다.

전류인가위치에 따른 매설지선의 과도접지임피던스 특성 (Transient impedance characteristics of counterpoise according to the current injection position)

  • 이복희;이봉;이승주;유재덕;조성철
    • 한국조명전기설비학회:학술대회논문집
    • /
    • 한국조명전기설비학회 2009년도 춘계학술대회 논문집
    • /
    • pp.328-331
    • /
    • 2009
  • This paper presents the behaviors of transient and conventional grounding impedances of a 30m counterpoise according to the injection point of lightning 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 greatly influences on the transient grounding impedance characteristics of counterpoise. The transient grounding impedances strongly depend on the injection point and the rising time of impulse current and the soil characteristics.

  • PDF

접지시스템의 설계를 위한 대지저항률의 합리적인 측정방법 고찰 (Examinations on the Reasonable Measuring Methods of the Soil Resistivity for Design of Grounding System)

  • 이복희;김기복;이승훈;최종혁
    • 조명전기설비학회논문지
    • /
    • 제25권6호
    • /
    • pp.35-41
    • /
    • 2011
  • In order to design effectively the grounding system, it is very important to determine the optimum soil resistivity at the desired location of the connection to earth. This paper deals with the reasonable methods of measuring the soil resistivity where grounding electrodes are buried. The soil resistivity at three test sites with different resistivity of soil were measured as functions of the spacing between the test probes in the Wenner's four-point method and the length of test ground rod in the three-point method. In the case of the three-point method, the length of test ground rod of 2-10[m] in length was appropriate in two-layered soil structure. In the length range of 2-10[m], the results measured by the three-point method using the test ground rod with the length corresponding to the spacing between the test probes of the Wenner's four-point method are in good agreement with the data obtained from the Wenner's four-point method.