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최영도,백자현,전동훈,박상호,최순호,김여진,허진,Choy, Youngdo,Baek, Jahyun,Jeon, Dong-Hoon,Park, Sang-Ho,Choi, Soonho,Kim, Yeojin,Hur, Jin 한국전력공사 2019 KEPCO Journal on electric power and energy Vol.5 No.3
In order to integrate large amounts of variable generation resources such as wind and solar reliably into power grids, accurate renewable energy forecasting is necessary. Since renewable energy generation output is heavily influenced by environmental variables, accurate forecasting of power generation requires meteorological data at the point where the plant is located. Therefore, a spatial approach is required to predict the meteorological variables at the interesting points. In this paper, we propose the meteorological variable prediction model for enhancing renewable generation output forecasting model. The proposed model is implemented by three geostatistical techniques: Ordinary kriging, Universal kriging and Co-kriging.
Real-Time Hardware Simulator for Grid-Tied PMSG Wind Power System
최영도,한병문,이준영,장길수 대한전기학회 2011 Journal of Electrical Engineering & Technology Vol.6 No.3
– This paper describes a real-time hardware simulator for a grid-tied Permanent Magnet Synchronous Generator (PMSG) wind power system, which consists of an anemometer, a data logger, a motor-generator set with vector drive, and a back-to-back power converter with a digital signal processor (DSP) controller. The anemometer measures real wind speed, and the data is sent to the data logger to calculate the turbine torque. The calculated torque is sent to the vector drive for the induction motor after it is scaled down to the rated simulator power. The motor generates the mechanical power for the PMSG, and the generated electrical power is connected to the grid through a back-to-back converter. The generator-side converter in a back-to-back converter operates in current control mode to track the maximum power point at the given wind speed. The grid-side converter operates to control the direct current link voltage and to correct the power factor. The developed simulator can be used to analyze various mechanical and electrical characteristics of a grid-tied PMSG wind power system. It can also be utilized to educate students or engineers on the operation of grid-tied PMSG wind power system.
Air Layer Effect on the Performance Improvement of a Cross-Flow Hydro Turbine
최영도,신병록,이영호 한국유체기계학회 2010 한국유체기계학회 논문집 Vol.13 No.4
The purpose of this study is not only to investigate the effects of air layer in the turbine chamber on the performance and internal flow of the cross-flow turbine, but also to suggest a newly developed air supply method. Field test is performed in order to measure the output power of the turbine by a new air supply method. CFD analysis on the performance and internal flow of the turbine is conducted by an unsteady state calculation using a two-phase flow model in order to embody the air layer effect on the turbine performance effectively. The result shows that air layer effect on the performance of the turbine is considerable. The air layer located in the turbine runner passage plays the role of preventing a shock loss at the runner axis and suppressing a recirculation flow in the runner. The location of air suction hole on the chamber wall is very important factor for the performance improvement. Moreover, the ratio between air from suction pipe and water from turbine inlet is also significant factor of the turbine performance.
Effect of wave conditions on the performance and internal flow of a direct drive turbine
최영도,김창구,이영호 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.6
The purpose of the present study is to investigate the effect of wave conditions on the performance and internal flow of a newly developed direct drive turbine (DDT) model for wave energy conversion experimentally. All the experiments using the test turbine models are conducted in a 2-D wave channel. Monochromatic waves of various conditions of wave height and wave period are applied to the turbine performance test. The influences of turbine configuration on turbine performance are also investigated. Test results show that rotational speed, differential pressure, incident flow rate, maximum output power, and best efficiency of the turbine model vary considerably depending on the wave conditions. Installation of a front guide nozzle and a rear water reservoir to the test turbine improves the turbine performance. Large passage vortex occurs both at the front and rear turbine nozzles in turn through a reciprocating flow in the turbine passage.
비속도의 큰 변화가 극저비속도 원심펌프의 성능에 미치는 영향
최영도,카가와슈사쿠,쿠로카와준이치 한국유체기계학회 2006 한국유체기계학회 논문집 Vol.9 No.1
Efficiency of a centrifugal pump is known to drop rapidly with a decrease of specific speed ns. However, below ns=60 [min-1, m3/min, m], the pump characteristics are not yet clear. Therefore, present study is aimed to investigate the influence of large change of specific speed on the performance of a very low specific speed centrifugal pump. Moreover, influence of impeller configuration on the performance of very low specific speed pump is investigated. The results show that very low specific speed can be accomplished by reducing volute throat sectional area using circular spacer. Influence of the spacer's location and configuration in the discharge passage on the pump performance is very small. Best efficiency of very low specific speed centrifugal pump decreases proportionally to the specific speed but the best efficiency decreases on a large scale in the range of ns<40. Influence of impeller configuration on the pump performance and radial thrust of centrifugal pump are considerably small in the range of extremely low specific speed (ns=25).1. 서 론* 요코하마국립대학 대학원 공학연구원
최영도,쿠로카와준이치 한국유체기계학회 2006 한국유체기계학회 논문집 Vol.9 No.6
There are high expectations of improving the performance of a centrifugal pump in the range of very low specific speed which has been developed recently for the use instead of a conventional positive displacement pump. However, even though elaborated studies has been done for the pump intensively, the pump performance has not increased so much. Also, it is difficult to find detailed information from published literatures for suction performance of the very low specific speed centrifugal pump. Therefore, this study is aimed to improve the pump performance more and to make clear suction performance of the very low specific speed centrifugal pump. Recircular flow stopper is installed on the pump casing wall at the region of impeller outlet to improve the pump performance and J-Groove is also installed at the inlet of the pump casing for the purpose of suppressing occurrence of cavitation as well as improving pump performance. The result suggests that the simultaneous improvement of pump performance and suction performance of the very low specific speed centrifugal pump is possible by adopting optimum configuration of the recirculation flow stopper and J-Groove.1. 서 론* 요코하마국립대학 대학원 공학연구원
최영도,카가와슈사쿠,쿠로카와준이치 한국유체기계학회 2006 한국유체기계학회 논문집 Vol.9 No.1
Recently, according to the trend of small size in scale and high speed in rotation of turbomachinery, very low specific speed centrifugal pump is taking a growing interest because the pump is characterized by high head and low flow rate with convenience of manufacturing and maintenance compared with conventional positive displacement pump. However, the efficiency of the very low specific speed centrifugal pump drops rapidly with the decrease of specific speed. The purpose of this study is not only to examine the influence of casing type on the performance of centrifugal pump in the range of very low specific speed but also to determine the proper casing type for the improvement of pump performance. The results show that circular casing is suitable for the centrifugal pump in the range of very low specific speed and the influence of impeller configuration on the pump performance is very small. Radial thrust in the circular and volute casings is considerably small in the range of very low specific speed.1. 서 론* 요코하마국립대학 대학원 공학연구원