KSTAR 대전력 설비 현황 및 운전결과 분석

공종대(Jong-Dae Kong),홍성록(Seong-Lok Hong),황인성(In-Seong Hwang),김양수(Yaung-Soo Kim),엄대영(Dae-Young Eom) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.7

핵융합반응은 초고온의 플라즈마 상태에서 가벼운 원자핵들이 융합하여 무거운 원자핵으로 바뀌는 현상으로, 이 과정에서 감소된 질량이 막대한 에너지로 변환되는데 이를 핵융합에너지라고 한다. 핵융합에너지는 인류의 에너지 위기를 극복할 수 있는 최적의 대체에너지이며, 무한, 청정, 고효율에너지이다. 이에 국가핵융합연구소(NFRI)는 Green Energy 의 개발과 핵융합에너지 상용화 기술을 개발하기 위해 핵융합연구장치인 KSTAR(Korea Superconducting Tokamak Adavanced Research)를 제작하여 장치의 운전연구 및 기술 확보에 힘을 쏟고 있다. 또한 핵융합 관련 파생기술을 활용한 첨단 신사업 창출에 기여하고 있다. 본 논문에서는 KSTAR 1st Plasma 실험 시 KSTAR 장치에 전력을 공급하기 위한 전력설비 현황, 전력품질분석, 전력사용량 분석을 통해 향후 KSTAR 장치 운전을 위해 필요한 수전설비 증설, 무효전력보상장치 증설 등과 같은 전력계통의 효율화와 안정화를 위한 개선사항에 대해 기술하였다.

KSTAR 전력계통 안정화를 위한 무효전력보상 및 고조파 필터 시스템 설계

홍성록(Seong-Lok Hong),공종대(Jong-Dae Kong),황인성(In-Sung Hwang),엄대영(Dae-Young Eom),김양수(Yaung-Soo Kim),박병주(Byung-ju Park),유항규(Hang-Kyu Yoo) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.7

KSTAR(Korea Superconducting Tokamak Advanced Reseach)장치는 차세대핵융합연구장치로써 30개의 초전도자석으로 구성된다. 이 초전도자석에 전원을 공급하게 되는 PF (Poloidal Field) MPS (Magnet Power Supply)는 12상 Pulse 운전을 하게 되는데 이때 h=kp±1의 특성고조파와 90%에 가까운 무효전력이 발생되어 KSTAR 전력계통과 인근 부하장치에 치명적인 영향을 줄 수 있어 고조파와 무효전력을 동시에 보상할 수 있는 최적의 무효전력보상장치의 도입은 필연적이다. 본 논문에서는 KSTAR 1st Plasma 실험시의 무효전력과 고조파를 저감하기 위해 설치했던 즉, 1단계 기계식 스위칭에 의한 RPC(Reactive power compensator)의 보상특성의 평가결과를 기반으로 KSTAR 2009년 Plasma 실험에 대비하여 이의 운전특성과 설치 공간에 따르는 제약 등을 고려하여 최적의 RPC 설계를 도출하기 위해 실시한 TSC(Thyristor Switch Capacitor)기반의 RPC[1] 모의해석 결과와 기술적 사항을 소개하고자 한다.

강자성 가돌리늄 박막의 큐리 온도의 이동

이일수(Ilsu Rhee),추교진(Gyojin Chu),이의완(Eui-Wan Lee),이상윤(Sang-Yun Lee),이종용(Chong-Yong Lee),김양수(Yaung-Soo Kim),김동락(Dong-Lak Kim),이형철(H. C. Ri) 한국진공학회(ASCT) 1994 Applied Science and Convergence Technology Vol.3 No.3

가돌리늄 박막의 큐리온도를 자기화의 온도에 따른 변화를 측정함으로써 결정하였다. 박막의 큐리온도는 bulk계의 큐리온도보다 낮아지며 이 박막에서의 큐리온도의 이동은 두께가 얇아질수록 커진다는 것이 관측되었다. 이 실험결과를 유한축적 이론의 관점에서 분석한 결과 전이온도의 이동에 관련된 지수 λ는 0.82±0.13로서 이론적인 값의 1.48과 상치한다는 사실이 발견되었다. 이러한 유한계의 실험치와 유한축척이론과 차이는 여러 유한계에서 관측되었다. We determine the Curie temperature of thin gadolinium films by the measurement of magnetizations as a function of temperature. From this measurement, we observe the systematic shift of Curie temperatures for films, that is, the larger the shift is, the thinner the film is. By analyzing the data in light of finite-size scaling theory, we determine the exponent λ to be 0.82±0.13, not equal to the theoretical prediction of 1.48, which is already seen in other experimental works.

1차원 난류유동장내에서 축회전하는 구면두부Fin의 후류에 의한 열전달 특성의 연구

김양수 영남이공대학 1998 論文集 Vol.27 No.-

This study was carried out to investigate the heat transfer characteristics by wake effect for the axial rotating fin of spherical surface in one dimensional turbulent flow. The results by mass transfer experiment using naphthalene sublimation technique and the measurement of pressure distribution at the front and back of the fin. 1. The rotating fin has comparatively high value than the fixed one(comparison of Fig. 7 and Fig. 4. 5 and 6). According to the increase of Reynolds number, the mean Nusselt number increased. However they are not proportion to the change of relative length. In the case of the fixed fin, the relative length(UD) has shown its maximum value around 0.5. On the contrary the rotating fin, the tendency has varied from the difference of circular velocity as shown in Fig. 4. 5 and 6. 2. The correlating formula has obtained like table 1, 2 and 3 owing to the variance of L/D and Reynolds number at the rotating spherical type fin.

回轉하고 있는 圓錐形 物體 周圍에 對한 强制對流 熱傳達特性에 瓘한 實驗的 硏究

金良洙 영남이공대학 1987 論文集 Vol.16 No.-

Mass Transfer measurements via the naphthalene sublimation technique have been performed to determine the heat(mass) transfer coefficient for the rotation truncated cone which situated on the center of the tube. Experiments were performed with variations of the angle θ 6˚, 16˚, 30˚, and Reynolds No. 3X10³ 9X10³ From the experiments, it was showed that there was a correlation between Nusselt No. and Reynolds No. of the induced flow and Reynolds No. of the peripheral flow. If the Reynolds No. of the peripheral flow was smaller than the Reynolds No. of the induced flow, the heat transfer coefficient was mainly dependent with the Reynolds No. of the induced flow. When larger, the coefficient was dependent with the Reynolds No. of the peripheral flow. On the other hand, when the Reynolds No. of the induced flow was Iarger than the Re. No. of the peripheral flow, the larger the cone angle, linearly the smaller the Nusselt No. But alternative case, Nusselt No. was inclined to decrease abruptly from 6˚ to 16˚ and to increase from 16˚ to 30˚ because of flow characteristics.

1차원 난류유동장내에서 축회전하는 원추형 Fin의 후류 효과에 의한 열전달 특성의 연구

김양수 영남이공대학 1996 論文集 Vol.25 No.-

Heat transfer chacteristics by wake effect on the back surface of rotating fin of truncated cone type were investigated in a small wind tunnel. Naphthalene sublimate technique was applied to mass transfer experiment. And the pressure distributions of the front and rear fm were measured. The fin angles,θ used for the experiment were 30°, 60°. 90° , 120° , and 150° . The Reynolds number were varied from 8,000 to 45,000 and circular velocities were 03, 0.6 and 1.2 m/s. The Nusselt number of the rotating fm has greater in tendency than that of fixed fin. And the maximum value was in the cone angle 60° of both of fixed and rotating fin. The experiments has shown that them is a correlation between Nusselt and Reynolds numder. (Table. 1, 2, 3)

반구두부를 갖는 Fin 후면피 후류에 의한 열전달 특성의 실험적 연구

김양수,김우섭 영남이공대학 1991 論文集 Vol.20 No.-

In order to investigate and forced convection heat transfer characteristics for wake effects on back surface of hemispher fin equipped in small wind tunnel, mass transfer experiment applied naphthalene sublimation technique and measured results of pressure distribution of test piece of front and rear are considered. Mean Nusselt number is increased with the increasing of Reynolds number. Neat transfer in proportion to the charge of hemispher fin shows maximum value with the Reynolds number. When relativity length is less than 0.5, the amount of heat transfer is influenced by the charago of Reynolds number and relativity length. But, it is more than 0.5, it is primarily decreased with the increasing of Reynolds number.(Fig.4) Pressure coefficient shows the repeating cycle of increase and decrease with the increasing and changeof Reynolds number and less then relativity length 0.5.(Fig.6) In each relativity length, the relation formula and the change of mean Nussclt number on the back surface of hemispher fin in melioration to the change of Reynolds number is described in table. I.

원추형 Fin후면의 후류에 의한 열전달 특정에 관한 실험적 연구

김양수 영남이공대학 1989 論文集 Vol.18 No.-

In order to investigate heat transfer characteristics for wake effects on back surface of turncated cone type equipped in small wind tunnel. mass transfer experiment applied naphthalene sublimation technique and measured results of pressure distribution of test piece of front and rear are considered. Mean Nusselt number is increased with the increasing of Reynolds number. Heat transfer in proportion to the charge of cone angle showl maximun value with the Reynolds number. When cone angle is lass than 60˚ the amount of heat transfer is influenced by the charage of Reynolds number and cone angle. But, it is more than 90˚ it is primarily increased with the increasing of Reynolds number. (Fig. 4). Pressure coefficient shows the repeating cycle of increase and decrease with the increasing and change of Reynolds number and cone angle each other. (Fig. 6). In each cone angle, the relation formula and the change of mean Nusselt number on the back surface of turncated cone type fin in proportion to the change of Reynolds number is described in table 1.

수평으로 놓인 평면두부 원통 Fin의 후류효과에 의한 열전달 특성의 실험적연구

김양수,이상배 영남이공대학 1992 論文集 Vol.21 No.-

In order to investigate and forced convection heat transfer characteristics for wake effects on back surface of colum fin equipped in small wind tunnel, mass transfer experiment applied naphthalene sublimation techique and measured results of pressure distribution of test piece of front and rear are considered. Mean Nusselt number is increased with the increasing of Reynolds number, Nusselt decreased with increasing of relativity length. When relativity length is 0.25, Mean Nu number is maximum value in the relativity length 0.125, 0.25, 0.5, 1.0, 2.0. But Nu Mumber showes the decreasing when Nu Number is 0.125. When Re Number is more than 20000, Pressure coefficient not changed mostly, when it is less than 20000, Pressure coefficient increased suddenly. And Pressure coefficient is minimal value when relativity length 0.25. In each relativity length, the relation formula and the change of mean Nusselt number on the back surface of hemispher fin in proporation to the changr of Reynolds number is described in table. 1.

圓錐形 物體에 對한 强制對流 熱傳達 特性에 瓘한 實驗的 硏究

金良洙 영남이공대학 1987 論文集 Vol.16 No.-

Small wind tunnel experiments were performed to determine the average heat transfer coefficients and pressure coefficients for a truncated cone facing a uniform oncoming flow. The experiments covered the range of Reynolds numbers Re from 3X10³ to 40X10³and cone angles θ 6˚, 16˚, 30˚. These were important paramcte-ts. Mass transfer measurements by using the naphthalene sublimation technique were carried ont to obtain the average Nusselt numbers through the heat-mass transfer analogy, It was showed that average Nusselt number almost increased linearly with Reynolds number and each cone angle. and the correlations between the Re and Nu number were made in fully developed turbulent flow. Furthermore, it was found that the smaller the cone angle, the larger the Nusselt number. I thought it was influence of the flow characteristics is vortex flow, stagnation flow, etc.. Surface pressere coefficients of the downstream were decreased qualtatively by the Reynold number increased.