• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.472-475
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• 2002

A Rogowski coil can measure alternating currents from a few amps to over 1 million amps in a frequency range from less than 0.1 Hz to about lMhz. A Rogowski coil provides an induced output voltage which is proportional to the rate of change of the primary current enclosed by the flexible or the rigid coil-loop. Therefore, it is necessary to integrate the output voltage in order to produce a voltage proportional to the current. Also. it can reproduce the current waveform on an oscilloscope or any type of data acquisition device. This paper describes the practical design of the combination of a Rogowski coil and an integrator which provides a versatile current measuring system to accommodate a wide range of frequencies, current levels and conductor sizes.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.170-176
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• 2003

The pantograph for Korean High Speed Train was developed and had been evaluating by through "G7- R＆D for home grown high speed train technology". In this study, a relation in mechanical aspect between the train running speed and the current collecting performance of the pantograph is conducted.'for this study, a measuring system for current collecting performance and mechanical characteristics is developed and installed on the prototype Korean High Speed Train, and measurement is conducted while the train runs on the test track. The measuring system is composed of video monitoring system and telemetry & data processing unit. It monitors whether the hazard behavior in the pantograph is occurs or not, and measures acceleration and vertical contact force between the pan head and catenary. Through this study, evaluation of a mechanical vibration characteristics and trend of the pantograph and a interface performance of pantograph - catenary up to 200㎞/h train speed are facilitated.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.5
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• pp.502-507
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• 1999

An improved, accurate and reliable high-voltage measuring system utilizing a bushing-type capacitor is proposed in this study. This system measures voltages and phase angles of three-phase 22.9 kV power distribution lines and provides enough current to charge a battery for a motor-driven load switch and to operate the measuring and communication circuits for the distribution automation. For reliability, epoxy resin was used as the dielectric material of the bushing-type capacitor since the dielectric strength of epoxy resin is very stable over the wide range of temperature. Capacitances were investigated and found to be stable over the wide range of temperature and applied voltage, and the results indicate that the proposed measurement system is very reliable.

• Journal of the Korean Society of Safety
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• v.31 no.3
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• pp.47-52
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• 2016

This paper describes the design and fabrication of high frequency ground impedance measuring system for assessment of grounding system for Lightning protection. The ground impedance measuring system has been designed and fabricated which makes it possible to assess the ground impedance by frequency ranges from 100 Hz to 1 MHz. The effective grounding systems having a very low impedance to electromagnetic disturbance such as lightning surges and noises in microelectronics and high-technology branches are strongly required. In order to analyze the dynamic characteristic of grounding system impedances in lightning and surge protection grounding systems, it is highly desirable to assess the ground impedances as a measure of performance of grounding system in which lightning and switching surge currents with fast rise time and high frequency flow. The measuring system is based on the variable frequency power supply and consists of signal circuit part, main control part, data acquisition and processing unit, and voltage and current probe system. The ground impedance measuring system can be used to assess grounding system during occurrence of lightning.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.10
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• pp.44-51
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• 2012

The purpose of this study is development of the diagnosis system to preventative maintenance in the on-board measuring systems for in-cab electric inspection systems of high speed railway. The on-board measuring systems can inspect precisely whether ground signal system operate stably. In this paper, we recognize characteristics of the track circuits and confirm whether the wave of current matches the on-board measuring data through the electric modeling method for high speed railway. it is necessary to develop GUI visual programs that can simulate abnormalities of the on-board measuring data in many ways, and the visual program is designed to diagnosis in the case of track circuit equipment's function decreased in advance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05b
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• pp.47-50
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• 2002

The displacemant current measuring system used for detecting the dynamic behavior of monolayers at the air-water interface is described. It basically consists of a film balance, a pair of electrodes connected to each other through a sensitive ammeter. Here, one electrode is suspended in air and the other electrode is placed in the water. With Maxwell-displacement-current-measuring method, the phase transitons of $Poly-{\gamma}-benzyl_{L}$ -glutamate (PBLG) and $Poly-{\gamma}-benzyl_{D}$-glutamate(PBDG) on a water surface were detected. Measured surface pressure, displacement current and dipole moment of monolayers of PBLG and PBDG on the water surface. Also, we measured that compression velocity (30, 40, 50[mm/min]) when the sample spread volume was about 370[ul]-400[ul] and displacement current that occur when differed temperature. From the result, it is known that current is generated in the range of high surface pressures as compression velocity become faster and increase of temperature.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2045-2047
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• 1998

To store and maintain electron beams in synchrotron machines, it is very important to read and keep precise magnet current ($<{\pm}50$ ppm). However, accurate DC current measurement tools are not readily available. In this paper, we introduce high precision, wide band zero-flux current transformer that is manufactured and tested at Pohang Accelerator Laboratory. This sensor can measure DC as well as AC current. Accuracy of the current transformer is less than ${\pm}$20 ppm. Performance of the manufactured current sensor is compared with a high precision DCCT which is commercially available sensor.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.6
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• pp.43-48
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• 2001

This paper represents the design of the ground resistance measuring system insensitive to the noise in the earth. Generally, conventional ground resistance measuring instruments may fail to give a precise values for ground resistance under the situations where there is a high ground potential produced by unbalanced power system currents, haromonic currents and noise etc. To make up the defect of conventional ground resistance measuring instruments, in this paper the ground resistance measuring system using high-performance L-C resonant filter and digital signal processor is designed and the insentivity of the designed ground resistance measuring system for noise in the earth is verified by field test on power service and off power service.

• Journal of Korea Multimedia Society
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• v.20 no.7
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• pp.1046-1053
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• 2017

We propose a design method of high accuracy power measuring device and the method of securing the reliability of the measured data. As a design method for the development of the high accuracy power measuring device, the circuit was made by reflecting the high accuracy power measuring ICs and the CT (Current Transformer). To ensure the reliability of the power meter, we requested to the watt-hour meter certified testing organization to measure the error rate, and the error rate of active power based on the "Wattmeter Technical Standard(Revision notify 2014-283)" was measure, and the error rate was confirmed to be less than 0.1%.

• Journal of Sensor Science and Technology
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• v.20 no.4
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• pp.254-259
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• 2011

In this paper, a current stimulator circuit with adaptive supply regulator for retinal prosthesis is proposed. In current stimulation systems, the stimulating circuits with wide voltage swing range are needed due to the high impedance of the retina cell and microelectrodes. Thus, previous researches adopt the high voltage architecture to obtain the enough operating range. The high voltage architecture, however, could increase the power consumption and can damage the retina cells. The proposed circuit provides the adaptively regulated supply voltage by measuring the difference between desired stimulation current and the actual stimulation current. The proposed circuit can achieve the extended range of the allowable cell impedance, improved accuracy of the stimulation current, and higher biosafety.