• 전기학회논문지
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• 제64권1호
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• pp.188-195
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• 2015

This paper presents measurement error reduction technique of touch and step voltage of grounding system based on numerical analysis. When measuring touch and step voltage of grounding system, auxiliary current probes should be located at suitable places. However, the auxiliary probes can not be located at suitable places in such cases as there are buildings and pavements. Therefore, in this paper, we provided measurement error reduction technique of touch and step voltage of grounding system according to the positions of auxiliary probes and angle between auxiliary probes. Also, measurement error analyses of touch and step voltage of grounding system have been conducted using more than one current probe. Based on these analyses, recommended positions of auxiliary probes within allowable measurement errors were presented.

• 한국안전학회지
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• 제16권3호
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• pp.53-60
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• 2001

This paper presents a graphical method for hazard assessment of electric shock by safety criteria. For the human body to be safety actual body current should not exceed safety criteria, i.e. allowable body current. The assessment method presented in this paper is based m the safety criteria of the IEEE Standard 80 as well as the IEC 479-1. The hazard can be assessed in terms of alterable touch voltages instead of alterable body current. Thus, the hazard assessment of given electric shock condition is referred to a procedure by which the actual touch voltages are compared with the allowable (safe) touch voltages. Since the IEC 479-1 safety criteria are nonlinear, the graphical method is presented for the hazard assessment. Body current and body voltage are calculated with the allowable touch voltage. A comparison of the safety criteria of two widely accepted standards, i.e. the IEEE Std 80 End the IEC 479-1 is proposed. Also Thevenin equivalent resistance is obtained from electric shock model expressed by two-port earth-grid-foot system. On the basis of calculated results, the allowable touch voltage, the body current and the body voltage we can conduct the hazard or safety assessment and estimate the severity of electric shock.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2005년도 학술대회 논문집
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• pp.391-394
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• 2005

This paper describes the touch voltages and potential distributions according to the distance between distribution concrete pole and ground rod when the current is injected to a ground rod through overhead ground wire. Touch voltage is measured in four directions. The touch voltage and ground potential distribution per 1 A are analyzed. The touch voltage was the highest at the around surface just above the ground rod.

• 전자공학회논문지
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• 제52권4호
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• pp.71-79
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• 2015

본 논문에서는 상호 정전용량 터치스크린의 single line sensing 방법에서의 단점을 해결하기 위한 성능향상 구조를 제안한다. 제안 구조는 Dual sensing 기법과 voltage shifting 기법을 도입하여 센싱 신호의 노이즈를 효과적으로 제거하고 터치 유무의 센싱 신호 차이를 증가시킨다. Dual sensing 기법은 구동신호의 양방향 엣지를 사용하여 integration 속도를 2배로 증가시켜 감지시간을 감소시킨다. Voltage shifting은 ADC의 입력신호 동작범위를 최대화하여 신호 대 노이즈비 (SNR)를 개선한다. 23" 대형 상용 터치스크린을 이용하여 simulation 및 측정한 결과로 제안된 센싱기법은 43dB의 SNR 성능을 가지며, 기존 방식 대비 2배의 스캔 속도를 제공하여 대형 터치스크린을 위한 적합한 기술임을 보인다. 제안된 센싱기법은 현재 매그나칩 CMOS 0.18um 공정으로 TSP 컨트롤러칩으로 구현되었다.

• 전기학회논문지
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• 제58권1호
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• pp.113-118
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• 2009

Grounding systems set the reference voltage level of electric circuits and suppress the Ground Potential Rise (GPR) by flowing fault currents to the ground safely. There are several parameters which evaluate the performance of grounding systems as ground resistance, touch voltage and step voltage. The touch and step voltages, which is called "risk voltage", are especially important to ensure the safety of human body. This paper dealt with the influence of current sources with the different frequency components on the touch and the step voltages. Three types of current sources as commercial frequency, square wave, and surge with the fast risetime of $50\;ns{\sim}500\;ns$ were used to analyze the risk voltages in a grounding system. The risk voltages showed remarkable difference in the same current amplitude depending on the current sources, and increased linearly with the current amplitude in the same current source. From the experimental results, it was confirmed that the risk voltages can be evaluated by a small current application in large-scale grounding systems and the possible largest risk voltage can be calculated by a surge current with the risetime of 200 ns or a current source with the same frequency component as the surge current.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.311-315
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• 2008

Ground systems set the reference voltage level of circuit and system, and suppress Ground Potential Rise (GPR) by flowing fault currents to ground safely. There are several parameters which evaluate the performance of ground systems as ground resistance, touch voltage and step voltage. The touch and step voltages are especially important to ensure safety of human body. In this paper, we measured the touch and step voltages by injection of power frequency and surge current. Also correlation between touch and step voltages is compared and analyzed for the same ground systems.

• International Journal of Safety
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• 제9권2호
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• pp.1-5
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• 2010

In order to analyze the potential rise of ground surface of grounding grid installed in buildings, the grounding simulator has been designed and fabricated as substantial and economical measures. This paper describes the study of touch and step voltages with grounding grid where earth leakage current is injected. To assess risk voltage of grounding grid, the grounding simulator and CDEGS program were used to obtain measured data and theoretical results of this study. The grounding simulator was composed of an electrolytic tank, AC power supply, a movable potentiometer, and test grounding electrodes. The potential rise was measured by grounding simulator, and the touch and step voltages were computed by CDEGS program. As a consequence, the touch voltage and step voltage above the grounding grid were very low, but were significantly increased near the edge of grounding grid.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1474-1475
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• 2006

This paper describes touch and step voltage in the reinforced concrete and steel poles. Ground surface potential rises were measured as a function of the separation between pole and ground rod. Touch and step voltage are calculated on the basis of the distribution of ground surface potential rises. As a result, touch and step voltages strongly depend on the position of installation of ground rod.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2286-2288
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• 2005

This paper describes impulse grounding impedance and touch voltage when impulse current is injected to grounding systems for distribution concrete pole. Impulse grounding impedance is a significant factor in analyzing transient grounding impedance. The touch voltage is measured in four directions. The maximum touch voltage was 520V and the minimum touch voltage was 47.3V when the input current was 100A.

• 조명전기설비학회논문지
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• 제27권6호
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• pp.88-94
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• 2013

This paper proposes a capacitive touch switch using a switched-capacitor. The proposed method charges capacitance for measurement using the switched-capacitor until the voltage across the capacitance reaches a threshold voltage. As the proposed method uses the number of times being charged to measure the capacitance, the method has no relation with the operating frequency of the switched-capacitor. This paper also shows the quantization resolution of the proposed method is related to the capacitance in the switched-capacitor and the threshold voltage, i.e., the resolution is improved when the capacitance in the switched-capacitor is decreased and the threshold voltage is increased. Simulation result shows the method gives 31fF quantization resolution when the capacitance in the switched-capacitor is 50fF and threshold voltage is 80% of the supply voltage.