• The KSFM Journal of Fluid Machinery
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• v.12 no.6
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• pp.33-40
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• 2009

The temperature of vertical pump bearing metal in the pumped storage power plant has been high enough to shutdown the unit. Attempts such as decreasing the oil supply temperature, increasing the bearing oil gap etc. were performed to resolve the problem, but the issue was not resolved. Finally, the high bearing metal temperature was corrected by adjusting the bearing preload. The preload is formed by the oil wedge between the journal surface and bearing pad surface and the degree of preload is determined by the machined radial clearance, assembled radial clearance, rotor journal diameter etc. This paper focuses on the analysis of the preload depending on the bearing parameters and the result of the modification of the bearing following the analysis. The bearing metal temperature dropped as much as $20^{\circ}C$ which was similar as expected by software calculation. But the shaft vibration could increase when the assembled radial clearance is excessive. So, the adjustment of the bearing preload for the tilting pad type journal bearing should be carefully performed.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.567_568
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• 2009

In the past, pumping-storage generator pumped the water from the lower part storage to the upper part storage during the base load periods. And, it generated during the peak load or when other generator was outage. However, pumping-storage generator will operate different ways in the competitive power markets. It will pump during lower price periods and generate at higher price periods. This paper presents economic analysis of pumping-storage generator using price (or SMP) duration curve.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.13-16
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• 1988

As the automic power plant is increased, load leveling energy storage system becomes more important. Pumped hydroelectric storage, used in the present, has too storage efficiency and difficulty in selecting site. But SMES(Superconducting Magnet Energy Storage) has high storage efficiency (90%), fast time response characteristics and ease of location. The general object of SMES with electric power system is the minimization overall production cost. This paper presents a method for the economic operation of SMES by Dynamic Programming.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.905-907
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• 1993

Demand for electricity is increasing annually. Especially, the daytime demand grawth shows higher than any other time period. So the big difference between maximum and minimum electrical demand becomes another important problem to be solved. The Battery Energy Storage System is chosen as one of the solutions among the sevral methods. The purpose of utilization of Battery Energy Storage System is to improve the daily load factor. Also, Battery Energy Storage System may be used for the load levelling or the load shifting as well as the spinning reserve. Up to now, only the pumped hydro power plant system has been operated on the commercial basis, but this system has so many constraints such as site, environmental effects, construction period, ect. Being considered current electrical power situation the development of electric storage system is in need latly. Among the various electric storage systems, Battery Energy System is chosen with the top priority because it has sevral merits to cover such as the short construction period, the demand site installation, and the food environmental characteristics.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2062-2064
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• 2008

○○양수 발전소에서 운전되고 있는 SFC에서 양수모드 운전시 간헐적으로(1회/1-3개월) 승속실패(승속실패 시점은 대략 정격속도(300RPM)의 10%인 30RPM 전,후) 사례가 발생하나 SFC 제어 창에는 Alarm이나 Trip 관련 경보가 전혀 발생되지 않는 등 비정상 운전임에도 불구하고 원인을 파악할 수 있는 관련 정보를 취득할 수 없는 상황에서 SFC를 포함하여, 관련되어 운전되는 AVR, 인터페이스 판넬 등에 대하여 정밀점검을 시행하고, 원인을 규명함과 동시에 정상화 시킨 진단 사례임.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.211-213
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• 2011

통상 발전원으로서의 역할만을 담당하는 일반 화력발전기와는 달리 양수발전기는 발전원으로서의 역할뿐 아니라 계통운영의 경제성과 운영방향에 따라 부하로서의 역할을 수행한다. 이때는 동기기로서 조상기 혹은 전동부하가 되며 이로 인하여 일반 화력발전기와는 다르게 양수운전등 부하로서의 역할을 위한 또 다른 보호시스템을 적용하고 있다. 대용량 발전기와 전동부하로서의 역할을 겸용함으로써 필연적으로 나타나는 화력발전기와의 보호방식 차이를 비교 분석하고 보다 안정된 설비운전을 위한 보호시스템 적용에 대해 논하고자한다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.578-579
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• 2008

본 논문은 국내 전력시장과 동일한 규칙을 지닌 P-Pool 전산모형을 소개하였다. P-Pool 전산모형은 양수발전기의 입찰계획을 자동으로 생성하기 때문에 사용자가 입찰계획변경에 따른 SMP 변화를 분석하기 어렵다. 이를 해결하기 위해 본 연구에서는 양수발전기의 입찰계획량을 수요에 반영하는 방법을 제안하였고, 사례연구를 활용하여 검증하였다.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.393-396
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• 1991

The load factor is continuously decreasing with the increase of the daytime power demand so that the load levelling is required. Since the pumped storage power plant for the load levelling has some problems, new storage techniques such as the battery energy storage system (BESS) had been developed in the early 1980s. The MW BESS had been already interconnected to power system in the developed countries, while the 20KW BESS was developed and is being operated by KERI and KEPCO in our country, the development project of MW BESS is being persued now. Then, it is important to evaluate the economics and prospect of BESS. This paper presents the economic target and introduction prospect of BESS in korea.

• Korean Journal of Ecology and Environment
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• v.47 no.spc
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• pp.57-65
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• 2014

Spatial and temporal distributions of zooplankton were measured in an oligotrophic pumped storage-type hydroelectric reservoir which was composed of two reservoirs exchanging water daily, with water going up at night and going down during the day. Repetitive diel disturbance of the water column can be a unique feature of this reservoir system. Chl-${\alpha}$ concentration was highest in the early winter season. Phytoplankton density was lower in summer monsoon due to high flushing rate on rainy days. The zooplankton density was higher in the smaller upper reservoir possibly due to lower fish density in the upper reservoir. In the seasonal variation a time gap was observed between the phytoplankton bloom and the zooplankton bloom (particularly a rotifer, Keratella cochlearis). It is likely to that Keratella production is partially supported by heterotrophic food sources than phytoplankton. The dominance of a mixotrophic dinoflagellate (Peridinium bipes f. ocultatum) might have complicated the trophic relationship between phytoplankton and zooplankton. Our results provide some ecological information of zooplankton community in a highly disturbed alpine reservoir ecosystem relying on mostly allochthonous organic matter.

• Geomechanics and Engineering
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• v.16 no.1
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• pp.21-34
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• 2018

Discontinuities considerably affect the mechanical and hydraulic properties of rock mass. These properties of the rock mass are influenced by the geometry of the discontinuities to a great extent. This paper aims to render an account of the geometrical parameters of several discontinuity sets related to the surrounding rock mass of Rudbar Lorestan Pumped Storage Power Plant powerhouse cavern making use of the linear and areal (circular and rectangular) sampling methods. Taking into consideration quite a large quantity of scanline and the window samplings used in this research, it was realized that the areal sampling methods are more time consuming and cost-effective than the linear methods. Having corrected the biases of the geometrical properties of the discontinuities, density (areal and volumetric) as well as the linear, areal and volumetric intensity accompanied by the other properties related to four sets of discontinuities were computed. There is an acceptable difference among the mean trace lengths measured using two linear and areal methods for the two joint sets. A 3D discrete fracture network generation code (3DFAM) has been developed to model the fracture network based on the mapped data. The code has been validated on the basis of numerous geometrical characteristics computed by use of the linear, areal sampling methods and volumetric method. Results of the linear sampling method have significant variations. So, the areal and volumetric methods are more efficient than the linear method and they are more appropriate for validation of 3D DFN (Discrete Fracture Network) codes.