• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1948_1949
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• 2009

All the power generating station require dc auxiliary power systems to operate those dc components that must be available if a loss of ac power occur. Some examples of such components are auxiliary motors, circuit breakers, relays and solenoids. The dc source may be one common battery for both power and control or two separate batteries; one for power and another for control. Typically, a dc auxiliary power system is designed as an ungrounded system, instead of grounded system, so that a low-resistance ground fault on one of its two polarities will not affect the operation of the system, thus increasing system reliability and continuity of service. A ground detector should provide a high polarity-to-ground resistance so that a single ground fault occurring on the system will not affect the operation of that system. Sensitive relays have been known to energize momentarily while the cable and capacitive charge to ground shifts[1]. A power station had experienced this kind of incident and performed root cause analysis based on PC based simulation program known as PSpice. This simulation showed adapted relays on the system energize momentarily and design criteria on this relay should be corrected.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.245-249
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• 2009

Antarctic King Sejong Station was established in King George Island, the South Pole in 1988, and has been executing the monitoring studies on the change of antarctic natural environment. As an available power, the wind energy generator has been used in the form of hybrid with mainly diesel generator. Because the wind generation power sharply changes by wind energy, it must be careful during the system operation. When the power system becomes stable, the output performance of wind energy generator becomes stable. But, in case of unstable system, the errors frequently occur on the wind energy generator and it badly impacts the power system by output of wind energy generator. The purpose of this paper is to analyze suitability while operating the system of 10kW wind energy generator at Antarctic King Sejong Station, an isolated area, and to analyze the problem and improvements by power quality.

• Nuclear Engineering and Technology
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• 제19권2호
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• pp.99-106
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• 1987

가상적인 1,000MWe의 석탄화력발전과 원자력 발전소로부터 배출되는 방사성물질에 의한 피폭 영향을 상호 비교 연구하였다. 본 논문에서는 정상가동중에 배출되는 기체상 방사성물질에 국한하였으며 석탄화력발전소에 대한 방사선원은 국내자료가 부족하여 외국자료에 근거했고, 원자력발전소에 대해서는 표준발전소에 대해 계산된 방사선원을 사용하였다. 고리 기상탑의 1년 기상자료를 이용하여 Gaussian모델에 의해 방사성물질의 대기확산을 평가했으며, 개인 피폭선량은 대기확산인자가 최대인 지점의 성인에 대해 계산하였다. 방사선피폭선량은 석탄화력발전소보다 원자력발전소의 경우가 약간 컸으며 석탄화력의 경우는 원자력발전소와 달리 피폭선량의 73.5%가 오염된 엽채류의 섭취에 따른 것이었다.

• 전력전자학회논문지
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• 제27권5호
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• pp.425-430
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• 2022

A pumped storage power station is an important means to solve the problem of peak load regulation and ensures the safety of power grid operation. The doubly fed variable-speed pumped storage (DFVSPS) system adopts a doubly fed induction machine (DFIM) to replace the synchronous machine used in traditional pumped storage. The stator of DFIM is connected to the power grid, and the three-phase excitation windings are symmetrically distributed on the rotor. Excitation current is supplied by the converter. The active and reactive power of the unit can be quickly adjusted by adjusting the amplitude, frequency, and phase of the rotor-side voltage or current through the converter. Compared with a conventional pumped storage hydropower station (C-PSH), DFVSPS power stations have various operating modes and frequent start-up and shutdown. This study introduces the structure and principle of the DFVSPS unit. Mathematical models of the unit, including a model of DFIM, a model of the pump-turbine, and a model of the converter and its control, are established. Fast power control strategies are proposed for the unit model. A 300 MW model of the DFVSPS unit is established in MATLAB/Simulink, and the response characteristics in generating mode are examined.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.73-75
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• 2002

This paper presents the properly method of system security and facility countermeasures. We performed simulation for yearly peak of Korean power system in 2002 under the reactive power problem in a nuclear power plants. Analysis of the problems in power system operation by power flow, fault and stability study. Establishment of power system optimal operating plan by stabilizer and maintaining the reasonable voltage level.

• 대한전자공학회논문지TC
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• 제44권8호
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• pp.9-16
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• 2007

운용중인 기지국에서 각종 RF 파라미터의 측정은 매우 제한적으로 이루어지고 있으며, 일부 수행되고 있는 측정에서 조차 비교적 측정이 용이한 순방향 항목에 집중되고 있다. 본 논문에서는 기지국에 설치된 순방향 모니터링 포트를 이용하여 기지국의 역방향의 무선 품질을 측정이 기능한 측정장치를 설계하여 실제 운용 중인 기지국에서 검증시험을 실시함으로써 연구의 완성도 향상을 꾀하였다. 수신감도의 측정은 내장된 CDMA 모뎀을 이용하여 기지국과 음성호가 연결된 상태에서 폐루프 전력제어에 의한 모뎀의 출력을 감시함으로써 이루어질 수 있도록 하였다. 보다 정확한 계측을 위하여 모뎀의 TxAdj 파라미터와 함께 디텍터에 의한 실측 데이터를 이용하였다. 정확한 수신감도의 측정을 위해서는 트래픽이 없는 상황에서 측정이 이루어져야 하지만, 운용중인 시스템에서는 상황재현이 어려우므로 통화량 증가에 의한 수신감도의 열화정도를 보상함으로써 시간에 구애받지 않고 정확한 측정값을 얻을 수 있도록 $E_c/I_o$에 의한 보상기법을 적용하였다.

• 한국위성정보통신학회논문지
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• 제5권2호
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• pp.82-86
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• 2010

본 논문에서는 포락선추적 기능을 갖는 WCDMA 기지국에 사용될 수 있는 GaN FET를 이용한 전력증폭기 모듈을 설계하고, 제작 및 측정결과를 제시하였다. 개발된 전력증폭기 모듈은 소신호 RF 신호를 입력받아 고이득 MMIC 증폭기, 구동 증폭기 및 전력 증폭기 등을 거쳐 10W 이상의 출력을 생성할 수 있다. 또한, Envelope Tracking 응용을 위해서 최종 전력증폭기의 Drain 전압이 가변되어도 전체 모듈이 안정적으로 동작할 수 있도록 발진방지회로, Isolator, 음전압 우선인가 바이어스 회로가 설계되었다. 모든 바이어스 회로와 RF회로를 $17.8{\times}9.8{\times}2.0\;cm3$ 크기의 하우징 안에 집적화하여 소형화시켰다. 측정결과 바이어스 전압이 4V에서 28V까지 가변할 경우 30dBm에서 40dBm까지 출력이 가변되면서도 35%이상의 일정한 효율 특성을 나타내어 포락선 추적 기능을 수행할 수 있음을 확인하였다.

• 동력기계공학회지
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• 제12권2호
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• pp.18-22
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• 2008

A few intake stations have vibration problems caused by pipes. The vibration transffered from pipes excites building severely. Therefore, the crack is generated on building wall and people who work at intake station are damaged. In this paper, the vibration is measured and analysis is carried out for pipes at intake station in order to identify the usefulness and effectiveness of the solution proposed for pipe resonance avoidance. According to the result of analysis, the vibration of pipes is reduced by bellows.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1327-1330
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• 2004

An underwater robotic system has been developed and applied to visual inspection of reactor vessel internals. The Korea Electric Power Robot for Visual Test (KeproVt) consists of an underwater robot, a vision processor-based measuring unit, a master control station and a servo control station. The robot guided by the control station with the measuring unit can be controlled to have any motion at any position in the reactor vessel with $\pm$1 cm positioning and $\pm$2 degrees heading accuracies with enough precision to inspect reactor internals. A simple and fast installation process is emphasized in the developed system. The developed robotic system was successfully deployed at the Younggwang Nuclear Unit 1 for the visual inspection of reactor internals.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.775-778
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• 1992

In 1980, 154kV OF cable was installed at the Cheong-Pyeong pumped-storage power station. Effective head of this pumped-storage station is 250m between upper and lower re-servior and length of cable route is 750m. However, several failures have happened owing to steep slope during the operation. 154 kV XLPE cable was applied for this power station to eliminate a lack of stability on account of steep slope and successfully installed in 1991. Meanwhile, installation procedure brings about many problem to be solved. In this paper, we describe the counter measure of cable sliding phenomena caused by heat shrinkage as well as the method of installation of cable under the steep slope condition. And hereafter, we think this paper will be a good reference to design and installation of 154kV XLPE cables in steep slope turnnel at urban areas.