• The KSFM Journal of Fluid Machinery
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• v.2 no.2 s.3
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• pp.27-31
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• 1999

This paper describes the shaft vibration phenomena measured on a pump-turbine of a pumped storage power plant. The pump-turbine runs at a rotational speed of 450 rpm (7.5 Hz). The power output (load) of the pump-turbine is varied from 100 to 300 MW in the generating mode. The magnitude of the shaft vibration highly depends on the power load. The vibration magnitude of the shaft is very high in the middle load zone from 170 to 210 MW, elsewhere the vibration is low. From nitration spectra, it is shown that the frequency of major nitration in that load zone is 2.5 Hz which is approximately $34\%$ of the shaft rotating speed in Hz. This frequency component does not occur below and above that load zone. This subsynchronous vibration is caused by the flow induced disturbance due to spiral vortex flow downstream of the pump-turbine runner. Furthermore, the shaft vibration is highly decreased due to an increased bearing preload.

• 유체기계공업학회:학술대회논문집
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• 1998.12a
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• pp.166-172
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• 1998

This paper describes the shaft vibration phenomena measured on a pump-turbine ofa pumped storage power plant. The pump-turbine runs at a rotational speed of 450 rpm (7.5 Hz). The power output (load) of the pump-turbine was varied from 100 to 300 MW in the generating mode. It was found that the magnitude of the shaft vibration was highly dependent upon the power load. The vibration magnitude of the shaft vibration is very high in the middle load zone from 170 to 210 MW, elsewhere the vibration low. From vibration spectra, it was found that the frequency of major vibration in that load zone was 2.5 Hz which is approximately $34\%$ of the shaft rotating speed in Hz. This frequency component disappeared below and above that load zone. This subsynchronous vibration is caused by the flow induced disturbance due to spiral vortex flow downstream of the pump-turbine runner. Furthermore, it was found that shaft vibration was highly decreased due to the increase of bearing preload.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.1017-1022
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• 2001

Dam concrete for pumped storage power plants should have sufficient durability in repetitive wet and dry conditions and abrasion due to water level fluctuation and also in freezing and thawing resistance as well as permeability capacity. This study presents various experimental results to enhance the durability of face slab concrete in CFRD(concrete faced rockfill dam) by varying the fly ash substitution such as 0%, 15%, 20% and 25% and polypropylene such as 0%, 0.1%. The effect on durability of concrete corresponding to the increasing amount of fly ash and polypropylene was evaluated and the optimum quantity of fly ash and polypropylene substitution was recommended. The results show that 20% of fly ash substitution and 0% of polypropylene were found out to be an optimum quantity to achieve excellent performances in durability for face slab concrete in CFRD.

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.231-233
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• 2007

구조개편 이후 전력수급계획 수립여건이 한전의 독점적 계책에서 사업자 건설의향으로 전환됨에 따라 신규설비 건설계획은 수익성 위주로 전환되었다. 이에 따라 본 논문에서는 기저선비(원자력, 석탄화력) 운전효율성 항상 차원에서 건설되던 양수설비의 적정 설비규모를 계통 공급신뢰도 측면, 에너지 이응 효율성 향상 측면, 전력시장에서의 경제성 측면에서 검토하여 최적전원구성(Best Fuel Mix) 유도론 위한 정책적 방향을 제시하였다.

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.176-179
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• 2007

This paper proposes a fuzzy linear programming based solution approach fur the long-term generation mix with multi-stages (years) considering air pollution constraints on $CO_2$ emissions, under uncertain circumstances as like as ambiguities of budget and reliability criterion level. This paper approaches to generation mix problem for 2030 year in Korea eventually. The proposed approach may give more flexible solution rather than too robust plan. The effectiveness of the proposed approach is demonstrated by applying it to solve the multi-years best generation mix problem on the Korea power system which contains nuclear, coal, LNG, oil and pumped-storage hydro plants.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.1
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• pp.84-89
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• 2005

This paper presents a control algorithm for a large salient-pole synchronous motor fed by a Load Commutated Inverter (LCI). Many papers have been presented in the past few years on the justification, design, and application of variable-speed drive. The focus of this paper is on high torque operation and the estimation of initial rotor position. The results of simulation indicate that it is possible to produce the maximum torque and estimate the initial rotor position.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.298-299
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• 2006

This paper analyzes operation sensitivity of a relay, a blind spot of differential protection relaying, and how to protect the blind spot in protective relying of $3{\Phi}$ Y-Delta transformer consisting of three $1{\Phi}$ transformers which Korean pumped storage power plants have been using. Each different protective relayings must be adopted because there are differences between $3{\Phi}$ trans-former and $3{\Phi}$ transformer consisting of three $1{\Phi}$ trans formers. Also, in the system using high resistance grounding for fault current restriction of delta side, protection for delta side faults have to be considered properly.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.384-385
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• 2006

현재와 같은 경쟁적 전력수급 시장에서 경쟁력을 확보하기 위해서는 모든 발전사업자는 이득 극대화를 위한 전략이 필요할 것이다. 이에 여러 발전 방식 중에서도 타 에너지원의 발전설비보다 에너지원의 생산, 저장, 소비 등 다양한 전략이 가능한 양수발전을 선택하여 효과적인 대응 방안을 찾아보고자 한다. 본 논문에서는 발전 경쟁 시장 체제하에서 동적 게임이론을 적용하여, 양수발전을 소유한 발전 사업자의 최적 입찰 전략 알고리즘을 제시한다.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.319-322
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• 2005

This paper describes practical tuning methods and testing of a digital PSS, which uses both frequency and power, with the 220MVA Chungpyung P/P #1 in the KEPCO system to enhance the damping of local modes. In the first step, the objective phase of PSS is computed through a phase leading function to provide compensation between the exciter reference point and the generator air-gap torque before tuning the PSS's time constants. In addition, eigenvalue analysis was used to determine a range of PSS's gain, whichis the more useful for field testing rather than a single gain value. The Real-Time Digital Simulator was used to verify safe operations of the PSS in the presence of disturbances, such as AVR step and three phase fault.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.384-386
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• 2006

This paper deals with tests on the reactive power output limit and the Over-Excitation Limiter (OEL) dynamics of generation unit. The suggested reactive limit test methods can identify the allowable maximum/minimum reactive power at 100% rated MW in the steady-state operation condition. The on-line OEL limit test method can identify the time characteristics of OEL with the generation output at 50% of the rated MW. These methods are validated by applying to Yang-Yang Pumped storage units of 282 MVA.