• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.534-537
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• 1997

Solar power systems have become popular in the modem electric energy system. In order to supply the DC power, generated by solar cells, to the electric power system, the solar power system requires DC-to-AC power conversion. A line-commutated inverter or a forced-commutated inverter can be used in the DC-to-AC power conversion. Because of the nonlinear V-I characteristics of the solar cells, multiple operating points determined by the control mode of the inverter exist in the DC V-I state plane of the solar power system. In this paper, the stability of utility-interactive solar power system with a line-commutated inverter is analyzed at various operating points, using the eigenvalue method and the state-plane analysis technique. The stability of a forced-commutated inverter case is also anaiyzed and compared to that of the line-commutated inverter case.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.12
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• pp.2084-2090
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• 2007

The DGA (Dissolved Gases Analysis) technique has been widely using for fault diagnosis of the power transformers. Some electric power utility company establishes the criteria of DGA to improve reliability, because of difference of operation environment and design of power transformer. In this paper, we introduce intelligent diagnosis system for DGA result of KEPCO (Korea Electric Power Cooperation). This system can classify patterns type of gases ratio that frequently occurs in recent result of gases analysis using Fuzzy Inference. The classification of Patterns let us know that major causes of gases generation based on type of patterns. Finally, Neural Network based on patterns diagnose transformer. NN was trained using result data of DGA of actually faulted transformers recently. Result of intelligent diagnosis system is right well in comparison with actual inner inspection of transformers.

• Journal of Korean Institute of Industrial Engineers
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• v.7 no.1
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• pp.21-31
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• 1981

This paper develops a short term forecasting model for household electric power consumption in Seoul, which can be used for the effective planning and control of utility management. The model developed is based on exponentially weighted moving average model and incorporates monthly average temperature as an exogeneous factor so as to enhance its forecasting accuracy. The model is empirically compared with the Winters' three parameter model which is widely used in practice and the Box-Jenkins model known to be one of the most accurate short term forecasting techniques. The result indicates that the developed hybrid exponential model is better in terms of accuracy measured by average forecast error, mean squared error, and autocorrelated error.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.4
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• pp.16-20
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• 2014

To prevent any accident in electric power utilities, many researches for inspection and diagnosis deteriorations occurring by corona discharges have been continuously studying. Inspection and diagnosis of electric power utility is very important to prevent an accident. This paper studies a measurement of ultra-violet(UV) ray of corona discharges on polymer insulators using an UV sensor array with an optic lens. The detection of an UV signal begins at 60kV, which is about 37.5% of the breakdown voltage of the polymer insulator and the stronger the high voltage increased to the polymer insulator was. It can be determined that the polymer insulator mounted on a live part must be examined when the discharge risk exceeds approximately 40%. In conclusion, the status of power utilities can be checked using an UV sensor.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.591-594
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• 2005

Islanding of PV systems occurs when the uitilty grid is removed but local sources continue to operate and provide power to local loads. Islanding Is one of the serious problems in an electric power system connected with dispersed power sources. Also, this scan present safety hazards and the possibility of damage to other electric equipments. If the real and reactive power of RLC load and PV system are closely matched, islanding phenomena can't be detected by the passive methods. Several active methods were proposed to detect islanding phenomena. The most effective method is SFS method which was suggested by Sandia National Laboratory. In this paper, a new anti-islanding algorithm is proposed and its validity is verified through simulation and experimental results for utility interconnection of PV system.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.54-56
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• 2005

The paper proposes the solar photovoltaic power generation system method for photovoltaic system to solve the power shortage due the sudden power demand. So that supplied electric power to system at appearance during surplus electric power minute and unit moment link driving with common use system is available, digital PLL circuit system voltage through composition and phase of solar photovoltatic power generation system to do synchronization do. Feed forward controller was applied to get fast current response Solar cell that is changed by solar radiation always kept the maximum output when it used Step up chopper. The dynamic character had checked through simulation used Matlab Sumulink and confirmed through an experiment.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.687-689
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• 2000

Molten Carbonate Fuel Cell (MCFC) with high electrical efficiency and low environmental effect has been developed for the commercial application of power generation fields. Recently we have built a 25 kW molten carbonate fuel cell power generation system and tested it. The MCFC system is composed of diverse peripheral units such as reformer, pre-heater, water purifier. electrical loader, gas supplier, and recycling systems. The stack itself was made of 40 cells of $6.000 cm^2$ area each. The stack showed an output of 28.6 kW power and a reliable performance at atmospheric operation. while in pressurized operation the stack showed an output 25.6 kW lower than the atmospheric operation. The reason of lower performance of pressurized operation was caused from a gas cross over shown in few cells in the stack.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.695-697
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• 1996

Main theme of this paper is to evaluate the degree of risk due to the uncertainly of the future, especially for the long-term integrated resource planning (IRP) in electric utility. The measures of uncertainty for dealing with planning risk in the IRP context include robustness and flexibility of each candidate resource plan. The uncertainty indices are treated as decision criteria, or attributes, same as economic efficiency or reliability criteria in the multi-attribute decision-making (MCDM) procedure of IRP.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2597-2599
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• 2003

전력산업 환경변화에 따라 전력산업 전반에 걸친 고기능, 고효율의 정보기술(IT) 적용 필요성이 증대되고 있으며, 특히 향후 모바일 통신기술은 현장업무 처리능률과 고객에 대한 서비스를 대폭 향상시킬 수 있는 기술분야로서 연구개발의 필요성이 매우 클 것으로 예상되고 있다. 향후 무선인터넷 수요의 폭발적 증가가 예상되는 가운데 국내외적으로 이동통신업체를 포함한 제반 솔루션 공급업체, 민간/Utility 등 활용위주의 기업체, 학계 및 관련 연구소 등에서 향후 막대한 시장성과 성장성을 예측하여 모바일 컴퓨팅의 연구개발과 투자를 집중하고 있으며, 한전의 경우 G2B, B2B, B2E, B2C를 전반적으로 아우르는 다양한 업무범위와 전력업무 고유의 특수성을 감안한 때 모바일컴퓨팅 적용연구는 향후 이동통신의 최적 활용을 대비한다는 측면에서 연구개발을 추진하고 있으며, 본 논문에서는 연구개요 및 방향을 전반적으로 소개하고자 한다.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.27-29
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• 1994

Recently, the energy situation in Korea has been significantly changed. Rapid increase in electricity demand, tremendous financial need for new power plant construction, and environmental problem have led to search for more efficient energy production and energy conservation technologies. Due to the potential energy and cost savings to both electric utilities and industries, cogeneration will play an important role in the electric power and thermal energy supply in the future. In this study, we present the COGENMASTER computer model for optimal system configuration and economic analysis of cogeneration system. We also present several case studies with this module to analyze Korean cogeneration market. The result of this study will be useful to utility and industrial cogeneration planners for rapid analysis of cogeneration's value under a broad range of scenarios.