• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권10호
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• pp.597-601
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• 2004

A high bandwidth watt-converter, based on an inexpensive, commercially available, standard IC package, is described that covers a frequency ranges from DC to 100 kHz. The new resistive shunt for a wide-band frequency current measurement of the watt-converter was developed. The converter will use application in accurate power measurement under distorted and high frequency conditions. The advantages of the proposed watt-converter are its simplicity, low cost and fast response time.

• 한국통신학회논문지
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• 제32권3A호
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• pp.319-323
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• 2007

본 논문에서는 50-1000 MHz의 주파수 범위에서 전력과 임피던스의 표준을 이용하여 RF전압을 자동으로 정밀 측정을 하였다. RF-DC차를 결정하기 위하여 동축형 미소열량계와 자동 회로망 분석기가 이용되었으며, 총불확도는 약 1 % 이다. 써미스터 마운트의 실효효율과 열전압 변환기의 RF-DC차를 측정하기 위하여 HP 컴퓨터와 Commodore 컴퓨터, 그리고 IEEE-488 인터페이스 버스를 이용하고, 측정하는 전체과정이 자체 개발한 프로그램에 의해 자동으로 수행되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.75-79
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• 2000

This paper proposes the optimal placement with minimum set of Phasor Measurement Units (PMU's) using tabu search and makes an alternative plan to secure the robustness of the network with PMU's. The optimal PMU Placement (OPP) problem is generally expressed as a combinatorial optimization problem subjected to the observability constraints. Thus, it is necessary to make a use of an efficient method in solving the OPP problem. In this paper, a tabu search based approach to solve efficiently this OPP problem proposed. The observability of the network with PMU's is fragile at any single PMU contingency. To overcome the fragility, an alternative scheme that makes efficient use of the existing measurement system in power system state estimation proposed. The performance of the proposed approach and the alternative scheme is evaluated with IEEE sample systems.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.160-161
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• 2006

To Improve the mean-life and the reliability of power cable, we have investigated thermal conductivity of XLPE insulator and semiconducting materials in l54[kV] underground power transmission cable. Specimens were made of sheet form with the nine of specimens for measurement. Thermal conductivity were measured by Nano Flash Diffusivity thermal conductivity measurement temperature ranges of XLPE insulator were from 20[$^{\circ}C$] to 90[$^{\circ}C$], and the heating rate was 1[$^{\circ}C$/mm]. In case of semiconducting materials. the measurement temperature ranges of thermal conductivity were from 20[$^{\circ}C$] to 60[$^{\circ}C$], and the heating rate was 1[$^{\circ}C$/min].

• 센서학회지
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• 제17권1호
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• pp.23-28
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• 2008

In order to measure bio-signals, it is desirable to build a fully implantable system which connects directly to neural pathways or body tissue. A design scheme for fully implementable measurement system is proposed in this paper. Consisting of an implanted module and an external system, the proposed scheme delivers power and data between the two modules. The external module sends power via inductive link using a simple H-bridge type oscillator. Also, the implanted module sends measured data to the external system utilizing R/F communication technique at a frequency of ISM band. A stable communication and operation is achieved as the two types of channels are separated. Implemented in a compact size enough to be implanted in human body, the system exhibits good performance in experimental studies.

• Journal of Biosystems Engineering
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• 제17권4호
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• pp.326-335
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• 1992

This study was carried out to develop a measurement and analysis system of ride vibrations of tractors. The system consists of a portable digital computer, a PCL-812 PG interface card for A/D conversion, two accelerometers, two signal conditioners, a DC-AC power inverter and a DC power supplier. The computer programs installed in the system for data acquisition and analysis were also developed. It was intended that the system should be cheap enough to be afforded by college laboratories but reliable in its functions of measurement and analysis. Characteristics of the components and methods used in the system development were discussed.

• 동력기계공학회지
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• 제11권4호
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• pp.98-102
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• 2007

In this study, a measurement method of leakage flow-rate for pneumatic driving apparatus is proposed. The existing measurement methods of leakage flow-rate of air need disassemble the test component. Therefore, there is no effective method to measure the leakage flow-rate while operating pneumatic driving apparatus. In this study, the leakage flow-rate is measured from the pressure change in an isothermal chamber that can realize isothermal conditions by stuffing the steel wool into it. Therefore, a wide range of flow-rate could be measured only from the pressure response and the leakage flow-rate can be measured during operating pneumatic driving apparatus. The effectiveness of the proposed method is proved by experimental results.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.1142-1147
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• 2002

For the evaluation of the DC motor noise and vibration, usually it is rely on human feeling because some kinds of noise are not definitely represented by measurement Instrument such as sound meter. But when we consider time signal of the noise and vibration. It is possible to represent them. And in this paper. it is suggested to study output current shape of the motor because it Is the source to make speed and torque variation of the motor. If the current shape is not stable. it makes operating state of the motor unstable and produces noise and vibration. By analyzing signal at time and frequency of noise and vibration and current shape. it is possible to automation of the noise and vibration measurement in the Production line.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 연구회
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• pp.33-37
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• 2001

Recently, the HFPD measurement testing is widely used in partial discharge measurement of HV machines because HFPD measurement testing receives less influence of external noise and has a merit of good sensitivity. Also HFPD testing is able to offer the judgement standard of degradation level of HV machine and can detect discharge signals in live-line. Therefore it is very useful method compare to previous conventional PD testing method and effective diagnosis method in power transformer that requires live-line diagnosis. But partial discharges have very complex characteristics of discharge pattern so it is required continuous research to development of precise analysis method. In recent, the study of partial discharge is carrying out discover of initial defect of power equipment through condition diagnosis and system development of degradation diagnosis using HFPD(High Frequency Partial Discharge) detection. In this study, simulated transformer is manufactured and HFPD occurred from transformer is measured with broad band antenna in real time, the degradation grade of transformer is analyzed through produced patterns in simulated transformer according to applied voltages.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.385-389
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• 2004

Test facilities for the wind turbine performance monitoring and mechanical load measurements are installed in Vestas 100 kW wind turbine in Wollyong test site, Jeju island. The monitoring system consists of Garrad-Hassan T-MON system, telemetry system for blade load measurement, various sensors such as anemometer, wind vane, strain gauge, power meter, and etc. The experimental procedure for the measurement of wind turbine loads, such as edgewise(lead-lag) bending moment, flapwise bending moment, and tower base bending moment, has been established. Strain gauges are on-site calibrated against load cell prior to monitoring the wind turbine loads. Using the established monitoring system, the wind turbine is remotely monitored. From the measured load data, the load analysis has been performed to obtain the load power spectral density and the fatigue load spectra of the wind turbine.