• 한국자기학회지
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• 제27권1호
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• pp.1-8
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• 2017

플라이휠 에너지 저장 장치(Flywheel Energy Storage System, FESS)은 회전 운동 에너지를 저장하는 플라이휠 부분과 저장된 회전 에너지를 전기 에너지로 변환시키는 전동기/발전기 부분으로 구성된다. 일반적으로 플라이휠의 회전축은 전동기 및 발전기의 회전축과 동축 일체형으로 연결되고, 이때 전동기 및 발전기의 전자기 토크특성에 따른 동특성 변화는 전체 플라이휠 에너지 저장 장치의 충방전 특성과 기계적인 출력에 영향을 미친다. 본 논문에서는 5[kWh] 급 플라이휠 에너지 저장 장치 용 3상 유도전동기의 설계방법과 회전자 슬롯 수 변화에 따른 토크리플 특성과 고조파 영향을 중점적으로 분석하였다. 먼저, 플라이휠 에너지 저장 장치의 용량과 관성 모멘트에 의한 회전운동에너지의 관계식으로부터 플라이휠 크기와 전동기의 회전자 크기를 산정하는 방법을 제안하였다. 또한 플라이휠 에너지 저장 장치의 회전축의 고속구동 조건을 반영하여, 고속운전 영역에서의 전동기 토크리플 저감을 위한 유도전동기 회전자 슬롯수를 선정하였다. 이로부터 본 논문에서는 전동기 회전축과 동축으로 구성된 플라이휠의 소음 진동을 줄이고 고효율 충방전 특성을 구현하고자 한다.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 추계학술논문요약집
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• pp.448-449
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• 2018

• 한국수소및신에너지학회논문집
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• 제20권5호
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• pp.410-415
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• 2009

A hydrogen cooling method is used in a power generator for removing the unnecessary heat due to the windage loss of a rotor and the joule heat of a stator. A MEA (Membrane Electrolyte Assembly) hydrogen generator has been developed and applied as a hydrogen supplying system for the cooling of a 350MW power generator. As a field application result, the average potential of eleven cells and the voltage efficiency were measured 2.26V/cell and 65.4% (Higher Heating Value) respectively at the hydrogen pressure of 6 Bar, the hydrogen flow rate of 9.1L/min, and the current of 150A.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.533-538
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• 2014

Power generator is one of the most important component of electricity generation system to convert mechanical energy to electrical energy. I t designed robustly to maintain high system reliability during operation time. But unexpected failure of the power generator could happen and it cause huge amount of economic and social loss. To keep it from unexpected failure, health prognostics should be carried out In this research, We developed a health prognostic method of stator windings in power generator with statistical data analysis and degradation modeling against water absorption. We divided whole 42 windings into two groups, absorption suspected group and normal group. We built a degradation model of absorption suspected winding using Fick's second law to predict upcoming absorption data. Through the analysis of data of normal group, we could figure out the distribution of data of normal windings. After that, we can properly predict absorption data of normal windings. With data prediction of two groups, we derived upcoming Directional Mahalanobis Distance (DMD) of absorption suspected winding and time vs DMD curve. Finally we drew the probability distribution of Remaining Useful Life of absorption suspected windings.

• Nuclear Engineering and Technology
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• 제35권3호
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• pp.179-190
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• 2003

The multiple steam generator tube rupture (SGTR) event scenario with available safety systems was experimentally and analytically evaluated. The experiment was conducted on the large scaled test facility to simulate the multiple SGTR event and investigate the effectiveness of operator actions. As a result, it indicated that the opening of pressurizer power operated relief valve was significantly effective in quickly terminating the primary-to-secondary break flow even for the 6.5 tubes rupture. In the analysis, the recent version of RELAP5 code was assessed with the test data. It indicated that the calculations agreed well with the measured data and that the plant responses such as the water level and relief valve cycling in the damaged steam generator were reasonably predicted. Finally, sensitivity study on the number of ruptured tubes up to 10 tubes was performed to investigate the coolant release into atmosphere. It indicated that the integrated steam mass released was not significantly varied with the number of ruptured tubes although the damaged steam generator was overfilled for more than 3 tubes rupture. These findings are expected to provide useful information in understanding and evaluating the plant ability to mitigate the consequence of multiple SGTR event.

• 한국가스학회지
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• 제20권4호
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• pp.58-64
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• 2016

차량에 사용되는 주엔진은 부하영역 전체에서 효율을 증가시키기 위해 커먼레일 디젤엔진을 사용하고 있다. 그러나, 발전기용 엔진은 아직도 기계적 구성엔진으로 캠으로 구동되는 연료분사밸브가 사용되어지고 있다. 또한, 발전기용 엔진 대부분은 50%이하의 부분부하가 적용되고 있다. 따라서, 전부하에 세팅된 차량용 디젤엔진을 부분부하에서 효율적인 운전을 하기 위해서는 연료분사시기 재조정이 필요하다. 본 연구에서는 시설물에 사용되는 엔진발전기의 운용특성을 파악하여 연료분사시기를 재조정함으로서 부분부하 연료소비율을 개선시킨 결과를 연구하고자 한다.

• 한국수소및신에너지학회논문집
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• 제33권6호
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• pp.819-826
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• 2022

Fuel cell systems are being supplied to households and buildings to reduce greenhouse gases. The fuel cell systems have problems of high cost and slow startup due to fuel processors. Greenhouse gas reduction of the fuel cell systems is also limited by using natural gas. The problems can be solved by using a hydrogen generator consisting of a reformer and pressure swing adsorption (PSA). However, part load operation of the hydrogen generator is required depending on the hydrogen consumption. In this paper, PSA operation strategies are investigated for part load of the hydrogen generator. Adsorption and purge time were changed in the range of part load ratio between from 0.5 to 1.0. As adsorption time increased, hydrogen recovery increased from 29.09% to 48.34% at 0.5 of part load ratio. Hydrogen recovery and hydrogen purity were also improved by increasing adsorption and purge time. However, hydrogen recovery dramatically decreased to 35.01% at 0.5 of part load ratio.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권6호
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• pp.411-420
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• 2000

The energy storage systems are being widely researched for the high quality of the electric power. The FES(flywheel energy system) is especially, on the center of the research because it does not make any pollution and its life is long. The FES converts the electrical energy into the mechanical kinetic energy of the flywheel and reconverts the mechanical energy into the electrical energy. In order to store as much energy as possible, the flywheel is supposed to be rotated with very high speed. The motor/generator of the FES should be high efficient at high speed, and generate constant torque with respect to the rotation. In this paper, a motor/generator employing a Halbach array of permanent magnets is designed and constructed to meet the requirements, and its characteristics are examined. The magnetic field is analysed by using the magnetic surface charge method. The armature winding is designed for the harmonic components to be minimized by using the FFT. The sinusoidal current for the motor driving are generated by the hysteresis current controller. A sample superconducting flywheel energy storage system is constructed with a duralumin flywheel which has a maximum rotating speed of 40,000[rpm] and a stored energy of 240[Wh] and its validity is examined through the experiment.

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.460-474
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• 2023

A simple but accurate mathematical model is crucial for dynamic simulations and controller design of helical coil once-through steam generator (OTSG). This paper presents a three-region movable boundary dynamic model of the helical coil OTSG. Based on the secondary side fluid conditions, the OTSG is divided into subcooled region (two control volumes), two-phase region (two control volumes) and superheated region (three control volumes) with movable boiling boundaries between each region. The nonlinear dynamic model is derived based on mass, energy and momentum conservation equations. And the linear model is obtained by using the transfer function and state space transformation, which is a 37-order model of five input and three output. Validations are made under full-power steady-state condition and four transient conditions. Results show good agreements among the nonlinear model, linear model and the RELAP5 model, with acceptable errors. This model can be applied to dynamic simulations and controller design of helical coil OTSG with constant primary-side flow rate.

• 한국해양공학회지
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• 제24권1호
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• pp.133-139
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• 2010

From the ancient times, there are waves in the ocean. And all the moving body have energy. We have a kind of hope to convert the wave energy into electric one. Finally we can find out a power generator mechanism that mainly use the principle of pulleys. We have made drawings for this and completed the wave energy converter. This wave energy converter consists of several pulleys, rope, generator, buoys and anchors. The distance between an anchor and buoy is changed according to the hight of waves. Several sets of anchors, pulleys and buoys can make the movement of rope, and the ropes wind up a converter axis. In case of 1 meter movement of the buoy, the winding distance will be amplified 2 or 3 times if we use several moving and fixed pulleys. Based on this concept, we developed 2 kind of prototypes. One is for the test in the laboratory and the other is for the field test. Through the two test, we could confirm the usability of this mechanism.