• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.3
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• pp.74-83
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• 2002

The maximun short circuit current of modern power system is becoming so large that circuit breaker is not expected to be able to shut down the current in the future In order cut over-currents, a system composed of a superconducting fault current limiter(SFCL) and traditional breaker seems to provide a promising solution for furture power operation. In present paper, three line-to-ground fault is assumed to happen at the center of 345kV transmission lines in a large capacity electric power system. The superconducting fault current limiter was represented using a commutation type, which consists of a non-inductive superconducting coil and current limiting element (resistor or reactor). from the viewpoint of current limiting performance, the prevention of the voltage drop at the load bus and comparision characteristics for two type SFCL. Desired design specification and operation parameters of SECL were also given qualitatively by the performance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.12
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• pp.2190-2195
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• 2011

Due to enhanced demands on quality, security and reliability of the electric power energy system, a microgrid has become a subject of special interest. In this paper, output characteristics of energy storage system (ESS) with an electric double layer capacitor (EDLC) and battery energy storage system (BESS) of a renewable energy based microgrid were analyzed under grid-connected and islanded operation modes. The microgrid which consists of photovoltaic and wind power turbine generators, diesel generator, ESS with an EDLC, BESS and loads was modeled using real time digital simulator. The results present the effective control patterns of the microgrid system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.4
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• pp.62-68
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• 2015

Subsynchronous Resonance is a condition where the electrical power systems composed of generator and transmission line exchange energy with mechanical turbine-generator system at the frequency of the combined below the subsynchronous frequency. Therefore, the frequency of power systems should be associated with the subsynchronous resonance. This paper describes subsynchronous resonance by flexible frequency operation. It focuses on the characteristics and behavior of subsynchronous resonance. The subsynchronous resonance is being conducted by real-time digital simulator and the IEEE benchmark model for subsynchronous resonance have been utilized for the test systems.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.828-829
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• 2011

This paper performs a comparison analysis of two types of HVDC system in Jeju power system. A traditional HVDC transmission system had been composed of line commutated converter based on thyristors and the development of semiconductors enables to apply voltage source converter using IGBTs. The detailed parameters of Jeju power system were considered to make a similar condition with real system in real time digital simulator. Two types of HVDC transmission system were modeled and simulated to compare their characteristics in Jeju power system. The simulation results demonstrate that the VSC-HVDC system has more stable performance due to the fast response speed than LCC-HVDC when the transmission capacity was fluctuated.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.253-255
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• 2008

병합장치(merging unit: MU)는 변류기(CT)와 변성기(VT)로부터 계측된 전류와 전압을 이더넷을 통해 샘플값(sampled value: SV) 메시지를 전송하는 IED이다. 본 논문에서는 병합장치(MU)의 통신 성능 테스트하기 위한 시스템을 구축하는 방법을 제시하였다. RTDS를 이용하여 계통을 모의하고 샘플값 메시지를 지원하는 과전류계전(OCR) IED를 구축 한 후 계통에 모의 고장을 통해 CB를 동작시킴으로서 성능을 확인하였다. 또한 상용 IED를 연결하여 CB 동작 테스트를 통해 구축한 통신 테스트 시스템의 상호운용성을 확인하였다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1118_1119
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• 2009

The power generated by a Photovoltaic(PV) cell depends on the operating voltage of the array, its voltage-current and voltage-power characteristic curves specify a unique operating point at which maximum possible power is delivered and the array is operated at its highest efficiency. PSCAD/EMTDC, which is a simulation tool for the transient analysis of an electric power system, was used to simulate the PV Cell system. So, in this paper, the PV cell components of the PSCAD/EMTDC were developed, and the Maximum Power Point Tracking(MPPT) modeling was used for the developed PV power system to find the maximum power.

• Journal of Electrical Engineering and Technology
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• v.10 no.6
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• pp.2249-2255
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• 2015

The use of voltage source converter multi-terminal direct current (VSC-MTDC) systems is anticipated to increase from the introduction of wind farms and super grids in the near future. Effective control of the DC voltage in VSC-MTDC systems is an important research topic. This paper proposes a new dynamic reference-based voltage droop control to control the DC voltage in VSC-MTDC systems more effectively. The main merit of the dynamic reference-based voltage droop control is that it can reduce the steady-state error in conventional voltage droop control by changing references according to the system operating conditions. The performance of the proposed control was tested in a hardware-in-the-loop simulation (HILS) system based on the OPAL-RT real-time digital simulator and four digital signal processing boards.

• Journal of the Korean Society of Safety
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• v.12 no.3
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• pp.97-105
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• 1997

Mo-99(Molybdenum) is the only source of Tc-99m(Technetium) which is most frequently used in nuclear medical diagnostics and the demand is on the increase recently. Separation and refining of Mo-99 was investigated by adsorption and desorption on alumina. At pH=0.63, adsorption isotherm of Mo was fitted by Redlich ＆ Peterson equation using the adsorption experimental data. It was found that the pore diffusion model ($D_p=1.4{\times}10^{-6}cm^2/s, K_f/=0.4 cm/s$) agreed well with batch adsorption experimental data. RTDs(Residence Time Distributions ) were measured and axial dispersion coefficients were obtained in the fixed bed absorber according to the changes of the flow rate using 0.05% -NaCl. From the adsorption experimental data, it was shown that the behavior of breakthroughs depended on flow rate. Mo recovery yield was increased as adsorption flow rate was increased and desorption flow rate was decreased.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.9
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• pp.451-459
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• 2002

This paper presents a method for modelling of the impedance locus in order to test the protective relay with dynamic. This paper has the two parts, the first part is the configuration of impedance locus with voltage magnitude, total impedance magnitude and angle. And the second part is the control of the locus speed with deviation of two frequencies. The proposed method is applied to two machine equivalent system with PSCAD/EMTDC to show its effectiveness.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.260-261
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• 2006

This paper describes a real time digital simulation method for the application of HTS tape to power devices. At present, in order to extend the power capacity of some area which has a serious problem of power quality, especially metropolitan complex city. there are so many problems such as ROW for cable line routes, space for downtown substations, and the environmental protection, etc. HTS technology is one of the best solutions. Simulation is required for safety before install of HTS power cable, a fabrication model used at the power system simulation. Here, in this paper, authors developed an algorithm connected with HTS by using Real-Time Digital Simulator(RTDS).