• Journal of Electrical Engineering and Technology
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• 제9권2호
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• pp.379-389
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• 2014

Low frequency oscillations (LFOs) are load angle oscillations that have a frequency between 0.1-2.0 Hz. Power system stabilizers (PSSs) are very effective controllers in improvement of the damping of LFOs. PSSs are designed by linearized models of the power system. This paper presents a new model of the power system that has the advantages of the Single Machine Infinite Bus (SMIB) system and the multi machine power system. This model is named a single machine normal-bus (SMNB). The equations that describe the proposed model have been linearized and a lead PSS has been designed. Then, particle swarm optimization technique (PSO) is employed to search for optimum PSS parameters. To analysis performance of PSS that has been designed based on the proposed model, a few tests have been implemented. The results show that designed PSS has an excellent capability in enhancing extremely the dynamic stability of power systems and also maintain coordination between PSSs.

• 제어로봇시스템학회논문지
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• 제15권12호
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• pp.1209-1215
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• 2009

This paper discusses a common message protocol for green power systems such as tidal, wind, photovoltaic, and solar systems. For this investigations and analysis, existing protocols such as ELCOM-90, TASE.1, ICCP/TASE.2 and SCADA were analyzed for the application of green power systems in view of real-time property and reliability. For the analysis, the practical example of green power system using SACADA and ICCP are investigated and discussed. As a future direction of this investigations, the feasibility analysis of manufacturing message specification(ISO-9560) for green power system is discussed.

• 동력기계공학회지
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• 제12권5호
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• pp.65-70
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• 2008

The purpose of this study is to verify availability of the acoustic emission in-situ monitoring method to the internal leak and operating conditions of the turbine major valves relating to safety for turbine operating and prevention of turbine trouble at nuclear power plants. In this study, acoustic emission tests are performed when the pressurized electro-hydraulic control oil flowed through turbine electro-hydraulic controller oil check valve and turbine power/trip fluid solenoid valve in the condition of actual turbine operating. The acoustic emission method was applied to the valves at the site, and the background noise was measured far the abnormal plant condition. To judge for the leak existence ell the object valves, voltage analysis and frequency analysis of acoustic signal emitted from infernal leak in the valve operating condition are performed. It was conformed that acoustic emission method could monitor for valve internal leak to high sensitivity.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.96-98
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• 2005

This paper describes a monitoring system that monitors power quality and undesirable accidents when distributed generations are connected to the power grid. Prior to develop and operate a physical monitoring system, we constitute a simulation device to simulate the monitoring processes for the situations. The simulation system consists of the server and the client that connected by communication line. This system has various functions to monitor the power quality and the connection situation. Those functions are generation, transmission, acquisition and analysis of the simulated power data. This research seems very important to get the reliable and intelligent connection algorithm through the result of simulated monitoring system. Also hereafter, as this system uses the remote monitoring system through network and constitute the data base(DB), it will play an important role in building the automation of power system efficiently and systematically.

• 조명전기설비학회논문지
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• 제15권2호
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• pp.21-30
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• 2001

본 논문에서는 UPFC(Unified Power Flow Controller)설치 전력계통에서 어떤 선로의 전력조류를 원하는 값으로 직접 제어함과 동시에 계통 전체의 전력조류해석을 행하는 선로조류제약을 고려한 전력조류해석 알고리즘을 제시하고 이 알고리즘을 UPFC에 의한 과부하선로의 과부하해소제어에 적용하여 UPFC 제어 방법을 제시하고 사례연구를 통하여 UPFC의 제어효과의 효용성을 입증하였다. 또한 효과적인 조류해석을 위한 UPFC의 직·병렬 전압원의 초기치를 설정하는 공식을 유도하였다.

• 한국압력기기공학회 논문집
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• 제15권1호
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• pp.33-39
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• 2019

An 1,500MW advanced power reactor required the standard design approval by a Korean regulatory body in 2014. The reactor has been designed to have a 4-train independent safety concept and a passive auxiliary feedwater system (PAFS). The full power risk or core damage frequency (CDF) of 1,500MW advanced power reactor has been reduced more than that of APR1400. However, the risk during the low power and shutdown (LPSD) operation should be reduced because CDF of LPSD is about 4.7 times higher than that of internal full power. The purpose of paper is to analysis design alternatives to reduce risk during the LPSD. This paper suggests design alternatives to reduce risk and presents sensitivity analysis results.

• 교육시설
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• 제16권1호
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• pp.43-50
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• 2009

This research is to analyze LCC of Heat Pump system in university building by reduction of electric power costs for education and incentive system for gas. Produced details item different expense of EHP and GHP equipment construction step and preservation administration step. Analysis result is as following. 1) Executed LCC analysis for target system after lowering whole curriculum reduction of electric power costs for education. Analysis result, energy cost-cutting effect of EHP appears greatly than GHP unlike existent study finding, EHP decided by economical system. 2) Sensitivity analysis executed by incentive 500,000 won per units and geometrical ration of gas expense by 1%. As a result, because lowering effect of electric charges appears greatly, EHP decided by more economical system than GHP. As research result of front is different from existent study finding, EHP by lowering of electric charges for alteration and education of governmental frequent volunteer system was decided by more economical system than GHP.

• 대한전기학회논문지:전력기술부문A
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• 제54권3호
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• pp.122-132
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• 2005

This paper presents a novel approach based on Prony method to analysis of small signal stability in power system. Prony method is a valuable tool in identifying transfer function and estimating the modal parameter of power system oscillation from measured or computed discrete time signal. This paper define the relative residue of time signal and propose the condition to select low frequency oscillation in each generator. This paper describes the application results of proposed algorithm with respect to KEPCO systems. Simulation results show that the proposed algorithm can be used as another tools of power systems analysis.

• 한국유체기계학회 논문집
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• 제2권2호
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• pp.39-45
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• 1999

Pumped-storage power plants pumps the water from the lower reservoir to the upper reservoir using the extra electric power at night and generates electric power in the daytime. Currently it tends to be a high-head large-capacity machine. In this paper, we developed the computer programs for vibration analysis of the pump/turbine and generator/motor rotor system considering electromagnetic force, hydrodynamic unbalance force, dynamic characteristics of guide bearings and add mass of water. This program was verified by applying it to the real model and calculating the critical speed, natural mode and unbalance response.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.766-768
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• 2005

Interstate electric power system, as an alternative for energy cooperation under regional economic bloc, has been hotly debated before progressing the restructure in electric power industry and rapidly expanded in many regions after 1990s. Especially, since northeast asia has strong supplementation in resource, load shape, fuel mix etc., interconnection of electric power systems in this region may bring considerable economic benefits. For the economic analysis, we implement ORIRES model developed by ESI, Russia. ORIRES is a linear programming (LP) model for electric power system operation and planning. Since ORIRES requires data relatively less than other model, it is suitable for northeast asia that has considerable restriction against required data acquisition. In this paper, we perform an economic analysis on interconnection in northeast asia.