• 대한전자공학회논문지TC
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• 제44권6호
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• pp.31-39
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• 2007

본 논문에서는 코드분할다중접속방식을 사용하는 이동통신 시스템에서 기지국의 순방향 송신전력 및 파일롯 전력 등 RF 파라미터를 실시가 또는 주기적으로 측정하여 분석함으로써 시스템의 장애를 미연에 방지하고 셀커버리지 확대, 가입자 수용용량 증가 등 최적의 서비스 품질을 확보하고 투자효율을 극대화하기 위한 방안을 제시하였다. 순방향 전력 측정에서는 디텍터 내의 국부발진기 주파수를 가변함으로써 모든 채널의 송신출력을 측정할 수 있도록 하였다. 채널전력의 측정에 의하여 통화량 증가에 따른 송신출력의 변화를 관찰할 수 있으며, 순방향 $E_c/I_o$ 와의 비교를 통하여 파일롯 채널의 전력을 유추함으로써 대전력증폭기 등 송신부 모듈의 열화를 판독할 수 있도록 하였다. 일련의 모든 측정에는 CDMA 레벨디텍터에 의한 정밀 계측에 이은 정확한 분석이 이루어져야 하므로 변조방식 차이에서 오는 Crest factor 가 상이함으로 인한 측정상의 오차를 극복할 수 있도록 설계하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1920-1923
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• 1991

An online RF power measurement is needed for the full-bridged MOS-FET RF power inverter because the output current and/or voltage waveform is other than sinusoidal. In order to satisfy the requirement, the online measurement of the output power of this type of RF power inverter by the use of the PC-98 personal computer has been presented. The current and voltage waveforms are sensed by the digital oscilloscope probes so as to obtain the instantaeous power and they are entered into the PC98 personal computer so as to average the instantaneous powers. The RF power of up to 1 kw at 1 MHz measured for the power inverter at the output transformer. This method was confirmed to be applied to evaluate the load resistance change with temperature.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.18-29
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• 2015

State Estimation (SE) is the basis of a variety of advanced applications used in most modern power systems. An SE problem formed with enough phasor measurement units (PMUs) data is simply a linear weighted least squares problem requiring no iterations. Thus, designing a minimum-cost placement of PMUs that guarantees observability of a power system becomes a worthy challenge. This paper proposes an equivalent integer linear programming method for substation-oriented optimal PMU placement (SOOPP). The proposed method uses an exhaustive search to determine a globally optimal solution representing the best PMU placement for that particular power system. To obtain a more comprehensive model, contingencies and the limitation of the number of PMU measurement channels are considered and embodied in the model as changes to the original constraints and as additional constraints. The proposed method is examined for applicability using the IEEE 14-bus, 118-bus and 300-bus test systems. The comparison between SOOPP results and results obtained by other methods reveals the excellence of SOOPP. Furthermore, practical large-scale power systems are also successfully analyzed using SOOPP.

• 에너지공학
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• 제11권3호
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• pp.230-236
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• 2002

전력계통 실시간 제어에서는 전압, 전류, 유효전력, 무효전력, 역률, 시스템 주파수 등 전력계통 변수들을 측정하는 것이 중요하다. 이 변수들은 전압과 전류의 동기화된 페이저 정보부터 추출할 수 있다. 따라서 전압 및 전류의 동기화된 페이저 측정은 실시간 전력계통 제어에서 매우 중요한 역할을 한다. 이런 이유로 동기위상측정장치가 개발되었고 본 논문에서는 동기위상측정장치의 설계와 구현한 것을 제시하였고 제작된 시작품을 RTDS(Real-time Digital Simulator)와 실험실에 있는 380 V 3상 배전계통에 적용하여 측정된 실험결과를 통해 개발된 시작품의 성능을 검증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1049-1053
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• 1999

It is important to measuring and monitoring about state vectors of power system for precise operation control. All state vectors cannot be measured because it is economically disadvantageous, so that some state vectors are determined using state estimator. Determination of observability is a important precondition of power system state estimation because state estimation can be performed when given power system is observable. Recently as time-synchronization technique progress, using the PMU(Phasor Measurement Unit), state vector can be measured directly so that voltage phasor and current phasor measurements can be used for power system estimation. In this paper, observability algorithm is proposed to determinate the observability with real/reactive injection power measurements and real/reactive lineflow power measurements of existing measurement system and with phasor measurements of PMU. The jacobian matrix is newly composed for state estimation with measurements of added PMU, and state estimation is performed with least square estimatior. Comparison between state estimation result of existing measurement system and that of measurement system added PMU is presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1262-1266
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• 1999

More precise operation and control is required to ensure the stability and security of modern large power systems that is a complicated and widely dispersed structure. To ensure the precise operation and control of modern power system, most of all, precise monitoring and measurement of the various state values of power system is required. This paper discusses phasor measurement unit using synchronization signals from the GPS satellite system- Synchronized Phasor Measurement Unit. Considering the power system operation state, the transmitting data format over modems is defined. To provide all available information, PMU process the measurements to generate three phase symmetrical component. This paper proposes the transmitted data format and implements the PMU model using EMTP/Models. The validity of proposed model is confirmed through several contingency on the simple power system.

• 한국생산제조학회지
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• 제24권5호
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• pp.496-501
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• 2015

In this study, calibration procedure of power assembly tools is suggested and methods are developed for calculating measurement uncertainty. Fist of all, the calibration of joint simulator bench (JSB) was carried out for maintaining traceability and the uncertainty components of JSB were analyzed. The influences of tool speed, tolerance, temperature and length of the adapter were examined by the torque measurement values through experiments. From this research, credibility for calibration results could be enhanced. This experimental results, being used as an effective tool for calibration of power assembly tools, will provide and improve the accuracy of the use of the power assembly tools.

• Nuclear Engineering and Technology
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• 제45권2호
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• pp.249-256
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• 2013

In accordance with the US Nuclear Regulatory Commission (US NRC), Regulatory Guide 1.20, the reactor vessel internals comprehensive vibration assessment program (RVI CVAP) has been developed for an Advanced Power Reactor 1400 (APR1400). The purpose of the RVI CVAP is to verify the structural integrity of the reactor internals to flow-induced loads prior to commercial operation. The APR1400 RVI CVAP consists of four programs (analysis, measurement, inspection, and assessment). Thoughtful preparation is essential to the measurement program, because data acquisition must be performed only once. The optimized design of a vibration and stress measurement system for the RVI CVAP is essential to verify the integrity of the APR1400 RVI. We successfully designed a vibration and stress measurement system for the APR1400 RVI CVAP based on the design materials, the hydraulic and structural analysis results, and performance tests of transducers in an extreme environment. The measurement system designed in this paper will be utilized for the APR1400 RVI CVAP as part of the first construction project in Korea.

• 한국경영과학회지
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• 제36권4호
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• pp.1-16
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• 2011

It is important not only to introduce the C4I(Command and Control, Communication, Computer, Intelligence) system for realizing the NCW(Network Centric Warfare) but also to evaluate the synergistic effect by the C4I system. However, the study effort for evaluating the system's synergistic effect is insufficient compared with introducing the system. Therefore, in this paper, we proposed a model that measures the synergistic effect of combat power by the warfare information system. To measure the synergistic effect of warfare information system, the network power must be considered, so we also proposed a new methodology for measurement of network power based on SNA(Social Network Analysis), not Metcalfe's law. A model we proposed is a model that measures the raised combat power by the network effectiveness. The methodology and model we proposed in this paper will be used usefully to analyze the practical effect of constructing future warfare information system.

• 한국항행학회논문지
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• 제17권6호
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• pp.664-671
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• 2013

본 논문에서는 항공기내에서 전력을 무선으로 측정할 수 있는 AEMS(Zigbee electric power measurement monitoring system)시스템을 제안한다. AEMS시스템은 현재 상용화되고 있는 전력 측정 시스템을 분석하여 이를 보완하고 항공기내에서도 전력 변화를 쉽게 알 수 있도록 최근 가장 이슈가 되는 스마트폰과 모니터링 시스템을 연결하여 설계하였다. 또한, 실시간 전력 측정 시스템을 도입하여 전기 사용량을 실시간으로 제어함으로써 보다 실용성 있는 전력계측 시스템을 구축하였다.