• Proceedings of the KSR Conference
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• 2001.10a
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• pp.343-349
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• 2001

In this study we examined the method to estimate numerically the amount of the regenerated power and the excess regenerated power produced in the DC electric power supply system for the urban light rail transit system. And their economic feasibilities are also studied. For this study DC electric power supply system is simulated and the numerical analysis of the regenerated power and the excess regenerated power are conducted. The study result on the sample system shows that the facility to consume the excess regenerated power or the inverting equipment to reuse the excess regenerated power in the electric substation is feasible economically.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.4
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• pp.419-425
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• 2020

DC distribution system has been evaluated as an excellent one in comparison with existing AC distribution network because it needs fewer power conversion stages and the full capacity of the equipment can be used without consideration for power factor. Recently, research and development on the implementation of DC distribution networks have been progressed globally based on the rapid advancement in power-electronics technology, and the technological developments from the viewpoint of infrastructure are also in progress. However, to configure a distribution network which is a distribution line for DC, more accurate and rapid introduction of analysis technology is needed for the monitoring, control and operation of the system, which ensure the system run flexible and efficiently. However, in case of a bipolar DC distribution network, there are two buses acting as slack buses, so the Jacobian matrix cannot be configured. Without solving this problem, DC distribution network cannot be operated when the network is unbalanced. Therefore, this paper presented a comprehensive method of analysis with consideration of operating elements which are directly connected between neutral electric potential caused by the unbalanced of load in DC distribution network with bipolar structure.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1726-1733
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• 2015

In order to study the effect of the high-altitude and dusty weather in northwest of China on the corona characteristics of transmission lines, a corona caged based experimental system with sandy and dusty flow condition is numerically investigated and designed. This system overcomes the difficulties caused by harsh environment and offers easy usage for off-site tests. The design parameters are mainly determined by the characteristics of strong sandstorm in northwest region and test requirements. By the comparison of numerical simulation of the particle diffusion in four programs with rectangular or circular air-duct, a practical technology, which introduces swirl to control the particle diffusion length, is obtained. Accordingly, the structure of round air-duct with swirl elbow in inlet and outlet of high level segment is selected as final program. Systems of control and measurement are designed at the same time. Field tuning results show that the test system could ensure the range of sandy and dusty coverage. The wind speed, sandy and dusty concentration could be controlled and meet the requirements of accuracy. The experimental system has many features, such as simple structure, easy to be assembled, disassembled, transported and operated, small space occupied.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.489-490
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• 2007

In order to construct a digital substation based on IEC61850, All of the utility company should used IEDs to be verified and also vendors should get a certification from the international conformance testing organizationsuch as KEMA. So KEPRI in charge of POWER IT project related to SAS was required to IED conformance testing system, which can perform the test previously. The system, KEPCO developed, consists of HMI, IED (Intelligent Electronic Device), network equipment, V/I generator etc

• Nuclear Engineering and Technology
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• v.53 no.2
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• pp.376-385
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• 2021

Probabilistic risk assessment (PRA) has improved its elemental technologies used for assessing external events since the Fukushima Daiichi Nuclear Power Station Accident in 2011. HRA needs to be improved for analyzing tasks performed under extreme conditions (e.g., different actors responding to external events or performing operations using portable mitigation equipment). To make these improvements, it is essential to understand plant-specific and scenario-specific conditions that affect human performance. The Nuclear Risk Research Center (NRRC) of the Central Research Institute of Electric Power Industry (CRIEPI) has developed an HRA guide that compiles qualitative analysis methods for collecting plant-specific and scenario-specific conditions that affect human performance into "narratives," reflecting the latest research trends, and models for analysis of tasks under extreme conditions.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2152-2153
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• 2011

According to a sharp increase in demand for electricity supply secure, and $CO_2$ regulation in accordance with global environmental problems and to solve problems, etc. These factor less pollution, higher energy conversion hyoyulin way that the new electrical equipment, nano-composites The rapid degeneration of the unit study utilizing the power that is required is Free. Accordingly, cables, transformers and switchgear (GIS)-capacity of power equipment, such as, high-voltage high-density along with the miniaturization of equipment have made angry the reliability of these devices is becoming a very important issue. Insulation materials used in electrical equipment for high voltage withstand, power equipment, power equipment due to aging and overloading caused by a weakening of the insulation failure and replacement in accordance with the age due to increased costs because of the reliability of electrical equipment should be secured should. Therefore, improved performance and longevity of insulation material is recognized as an important challenge. In this study, power isolation and degeneration of the unit for use in various parts of the molding epoxy resin to improve the insulation performance of the epoxy resin by varying the added amount of nano-SiO2 nanocomposites made epoxy/SiO2 analysis and breakdown properties of the experiment want to improve the electrical properties through the geometry.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.305-307
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• 2001

The wind power equipment of Ullung island is composed of a hybride type of wind powers and diesel generators. The wind power generation in Ullung island is, howerever, not smooth due to the small capacity and weekness of existing power systems and line. Therefore, it is the purpose of this study to describe the technical problems and its solution through the investigation of actual conditions.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.324-325
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• 2020

계통 연계용 PCS(Power Conditioning System)에 적용되는 미국 인증 규격은 UL1741로써 PCS의 하드웨어 안정성과 소프트웨어의 기능 및 안정성을 요구한다. UL1741은 연계 규정으로 IEEE 1547.1을 요구하고 있으며, 본 논문에서는 소프트웨어 기능 및 안정성을 요구하는 UL1741SA 항목을 검증하기 위하여 데베소프트사의 SIRIUS 장비를 이용하여 효과적이고 정합성 있는 시뮬레이션 결과를 도출한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4610-4615
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• 2013

In this study, optimal operation strategies to save the electric energy and power price in the building central cooling system is researched by experiments. The optimal strategies of demand response control and outdoor temperature reset control algorithms are applied by consideration the electric energy and power price according to the energy consumption characteristics. The suggested optimal control method shows better responses in the power price and energy consumption in comparison with the conventional one and saves energy consumption by 9.5% and electronic price by 15.7%, respectively.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.9
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• pp.1325-1330
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• 2010

The breakdown of any critical component of a turbine results in the outage of power plants. Unexpected failure decreases equipment utilization and causes enormous economic losses. Currently, we conduct conservative preventive maintenance for a maintenance period that is proposed by a vendor. In the rapidly changing business environment, reliability-based maintenance is required in order to remain competitive and reduce maintenance costs while maintaining the reliability of equipment. In order to determine an appropriate maintenance period for guaranteeing reliability, we must determine the failure probability by carefully analyzing the failure history of the equipment. In this study, we created a database of failure history for power-plant turbines, predicted the best repair time using the Weibull function, and investigated how the appropriate maintenance cycle can be determined.