• 조명전기설비학회논문지
• /
• 제20권4호
• /
• pp.72-77
• /
• 2006

본 논문은 인하도선의 설치에 따른 접지시스템의 임펄스전류에 대한 과도임피던스 특성을 다루었다. 임펄스전류를 심매설 봉상 접지전각과 그리드 접지전극에 인가하였을 때 임펄스전류의 상승시간과 인하도선의 길이에 따른 전위상승과 실효임펄스접지임피던스를 측정하고 분석하였다. 과도접지임피던스는 접지전극의 형상과 크기 및 임펄스전류의 파형과 인하도선의 길이에 강하게 의존하며, 인덕턴스가 최소화되도록 인하도선을 설치하는 기법이 과도접지 임피던스의 저감을 위한 중요한 요소이다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 하계학술대회 논문집 C
• /
• pp.1864-1866
• /
• 1996

Grounding is the art of making an electrical connection to the earth. In order to protect man, electrical and/or electric equipments from the lightning strokes, all the energy of lightning strokes must be diverted via a safe path to earth. It is essential to the transient grounding resistance against lightning strokes. In this paper, measurements and analyses of grounding surge impedance have been investigated. For measurements of grounding surge impedance the pulse generator was designed and fabricated. The pulse generator has rise time of 22.4 ns and pulse duration of $8\;{\mu}s$. The transient grounding resistance has been measuring by injecting low power and step current between the earthing system under test and a remote reference earth and measuring the potential rise caused by this current. As a result, the transient grounding resistance against lightning surge in the short time domain is much higher than steady state grounding resistance.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 E
• /
• pp.2296-2298
• /
• 1999

The stationary ground resistance and the transient ground impedance of grounding system are very important parameters in the field of lightning and surge protection. But, it is very difficult to obtain correct values of them in large-scale grounding system. In this paper, the stationary and transient ground impedances of a large-scale grounding system have been measured and analyzed under impulse currents. In order to obtain correct values of them, we have described Z-v(impedance vs ground potential rise) distributions and Z-t waveforms. The transient ground impedance of 36 [m] long three-parallel grounding piles have showed the inductive aspects and the hysterisis region under impulse currents.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 하계학술대회 논문집 E
• /
• pp.1589-1591
• /
• 1998

This paper presents experimental results of transient impedance characteristics investigated on the site of a large-scale grounding system using impulse current. The ground potential rise was measured while injecting an impulse current and the transient impedance was determined. As a results, the transient impedance was significantly greater than the stationary grounding resistance due to high inductance of ground conductors and leads.

• 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.

• 조명전기설비학회논문지
• /
• 제25권4호
• /
• pp.117-123
• /
• 2011

Lightning and switching surges propagating through the grounding conductors lead to transient overvoltages, and electronic circuits in information technology systems are very susceptible to damage or malfunction from the electrical surges. Surge damages or malfunctions of electrical and electronic equipment may be caused by potential rises. To solve these problems, it is very important to evaluate the ground surface potential rises and hazardous voltages such as touch and step voltages at or near the grounding systems energized by electrical surges. In this paper, the performance of grounding systems against the surge current containing high frequency components on the basis of the actual-sized tests is presented. The ground surface potential rises and hazardous voltages depending on impulse currents for vertical or horizontal grounding electrodes are measured and analyzed. Also the touch and step voltages caused by the impulse currents are investigated. As a result, the ground surface potential rises, the touch and step voltages near the grounding electrodes are raised and the conventional grounding impedances are increased as the front time of the injected impulse currents is getting faster.

• 한국전기전자재료학회논문지
• /
• 제11권8호
• /
• pp.587-595
• /
• 1998

Transient thermal analysis simulations are carried out using a modeling program to understand the human body model HBM ESD. The devices were simulated a one-dimensional device subjected to ESD stress by solving Poison's equation, the continuity equation, and heat flow equation. A ramp rise with peak ESD voltage during rise time is applied to the device under test and then discharged exponentially through the device. LDD and NMOS structures were studied to evaluate ESD performance, snap back voltages, device heating. Junction heating results in the necessity for increased electron concentration in the space charge region to carry the current by the ESD HBM circuit. The doping profile adihacent to junction determines the amount of charge density and magnitude of the electric field, potential drop, and device heating. Shallow slopes of LDD tend to collect the negative charge and higher potential drops and device heating.

• 조명전기설비학회논문지
• /
• 제20권1호
• /
• pp.65-70
• /
• 2006

본 논문은 임펄스전류에 따른 접지시스템의 과도 특성에 관한 것으로 임펄스 전류를 심매설 봉상 접지전극과 그리드 접지전극에 인가하였을 때 나타나는 과도접지임피던스를 조사하였다. 과도접지임피던스는 인가전류의 상승시간과 접지전극의 크기 및 형태에 강하게 의존하며, 접지전극의 인덕턴스는 짧은 시간 영역에서 접지시스템의 과도 접지임피던스에 크게 영향을 미치는 것으로 나타났다. 또한 심매설 봉상접지전극은 짧은 시간영역에서 과도접지임피던스를 줄이는데 효과적이었다.

• 한국정보통신학회논문지
• /
• 제5권1호
• /
• pp.133-143
• /
• 2001

본 논문은 직각파 및 뇌충격진류에 대한 봉상접지각의 과도임피던스 특성을 정상접지지항과 비교.분석하였다. 접지계는 단일$(\Psi10[mm], 1[m])$과 5[m]의 간격을 두고 서로 연접한 3연접 봉상접지극으로 구성하였으며, 과도 임피던스 특성을 분석하기 위하여 상승시간 30[ns], 펄스폭 $20[\mus]$의 직각파전류 발생장치를 설계 제작하였다. 실제 낙뢰에 의한 접지임피던스의 변화를 관찰하기 위하여, 국제규격 ANSI/IEEE, IEC에 규정되어 있는 뇌충격전류를 인가하여 이에 따른 특성변화를 측정.분석하였다. 접지계로 유입된 과도전류는 접지계의 전위를 상승시키며, 이 때의 전위상승과 유입전류의 비로써 접지임피던스를 산출하며, 뇌격전류에 대한 경제적인 보호 수준을 평가.예측하기 위하여 임피던스 파라미터를 측정결과로부터 산출하였다. 또한 연접에 따른 접지임피던스의 감소와 접지리드선이 미치는 영향도 분석하였다.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2005년도 춘계학술대회논문집
• /
• pp.248-253
• /
• 2005

Although DC ground resistance is a good index of grounding performance for grounding electrodes, it does not reflect the grounding performance during transient state. Besides, impulse ground impedance, which is defined by a ratio of the peak value of transient ground potential rise to the peak value of impulse current, cannot be an absolute index due to its dependence on impulse current shape. In this paper, ground impedance of various rod-type ground electrodes has been measured in frequency domain ranging from 1 Hz to hundreds of kHz. Equivalent circuit models of the ground rod have been identified from the measured values of ground impedance in frequency domain.