• Journal of Power Electronics
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• v.11 no.6
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• pp.793-800
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• 2011

This paper investigates the operational modes of buck dc-dc converters and their energy transmission methods. The operational modes of such converters are classified in two types, discontinuous conduction mode (DCM) and continuous conduction mode (CCM). In this paper, the critical inductance relation of DCM and CCM is determined. The equations of the output voltage ripple (OVR) for each mode are obtained for a specific input voltage and load resistance range. The maximum output voltage ripple (MOVR) is also obtained for each mode. The filter size is decreased and the minimum required inductance value is calculated to guarantee the minimization of the MOVR. The experimental and simulation results in PSCAD/EMTDC prove the correctness of the presented theoretical concepts.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.481-482
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• 2013

This paper presents the method to determine the battery capacity for controlling the wind power with BESS for stabilizing the output of HanGeong wind farm in accordance with grid codes for distributed generators in Jeju Island. To find appropriate capacity of BESS, three kinds of simulations are carried out : There are focused on smoothing control, the frequency fluctuation and the renewable energy resources standards, respectively. As the simulation result, maximum C-rates of BESS for the wind farm are calculated as 2C, 5C and 2C that are for each method and battery capacities have 25%, 20% and 10% of total capacity of HanGeong wind farm. Finally, simulations for this paper are carried out by using PSCAD/EMTDC.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.343-344
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• 2013

본 논문에서는 바이폴라 타입 DC 마이크로그리드의 전압 불균형을 보상하기 위한 전압 밸런싱 기법과 안정도 향상을 위한 제어기법을 제안하였다. 선로 임피던스와 부하 불균형에 의한 전압 불평형 문제를 해석하고 제안하는 기법을 통해 이를 해결하였으며 과도 상태에 대한 DC 배전계통의 안정도 향상기법을 개발하였다. 제안하는 시스템의 동작 타당성을 체계적으로 분석하기 위해 PSCAD/EMTDC 소프트웨어를 이용한 시뮬레이션 모델을 개발하고 그 성능을 검증하였다.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.388-389
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• 2013

This paper presents the method for the fluctuation smoothing control by using relaxation time variable control of battery. When the output power of wind farm is changed suddenly, it is necessary to control the output power of wind farm. The smoothing relaxation time is changed within limits of battery output power. Using the hybrid energy storage system (HESS) combined with battery energy storage system and electric double layer capacitor, it is possible to control the output power of wind farm. The capacity of battery is determined by considering the case of the disconnecting wind farm from the grid. To verify the proposed method, simulations are carried out by using PSCAD/EMTDC with actual data of wind farm in the Jeju Island.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.6
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• pp.267-273
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• 2005

This paper proposes a line-to-ground fault location algorithm for underground cable system. A feature of the proposed method is a new algorithm based on the analytic research which has not been tried until now. The proposed method firstly makes voltage and current equations using analysis of distributed parameter circuit for each of cores and sheathes respectively, and then establishes an equation of the fault distance according to the analysis of the fault conditions. Finally the solution of this equation is calculated by Newton-Raphson iteration method. The effectiveness of this proposed algorithm has been proven through PSCAD/EMTDC(Ver. 4.1) simulations.

• KIEE International Transactions on Power Engineering
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• v.4A no.2
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• pp.51-57
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• 2004

This paper describes the dynamic performance of a variable speed wind turbine system responding to a wide variety of wind variations. Modeling of the wind generation using power electronics interface is proposed for dynamic simulation analysis. Component models and equations are addressed and their incorporations into a transient analysis program, PSCAD/EMTDC are provided. A wind model of four components is described, which enables observing dynamic behaviors of the wind turbine resulting from wind variations. Controllable power inverter strategies are intended for capturing the maximum power under variable speed operation and maintaining reactive power generation at a pre-determined level for constant power factor control or voltage regulation control. The components and control schemes are modeled by user-defined functions. Simulation case studies provide variable speed wind generator dynamic performance for changes in wind speed

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1088-1090
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• 1998

The cogeneration facilities (COGN) into the power distribution system can cause operational problems - reenergization of distribution feeders under repair by utility personnel, voltage variation and regulation because of output power of COGN, and lost of coordination at emergency state - on an electrical utility system. This paper deals with momentary voltage dips as the parallel interconnection operation of COGN in the power distribution system. PSCAD/EMTDC simulation tool is used to show the behavior of momentary voltage dips. In addition, restraint solution for momentary voltage variation is presented.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1244-1246
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• 1998

This paper present a variety fault problem brought out with the multifunctional Battery Energy Storage System [MBESS] expected to be practical in the short future interconnected to power distribution system. Multifunctional BESS model and interconnection model to power system is simply configured, the problems of protection coordination and operation is studied. A line fault in the power distribution system are discussed such as line to ground and three phase fault in order to show the impact on power utilities, demand-side and BESS-side. In order to simulate a variable transient phenomenon due to 2 the BESS interconnection operation to power distribution system, in this paper, PSCAD/EMTDC simulation tools is used.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1182-1184
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• 1998

Recently high impedance fault(HIF), which includes arcing wave, has often occured in power system. Some papers related to arcing phenomena and its modeling have been published. However the proposed methods show much different form in compare with actual arc wave under HIF. It is not so available to use to analyze HIF because of such problem. This paper proposes the new arcing wave model, which is nearly similar to actual arcing wave, developed using PSCAD/EMTDC. The arcing waves obtained from arcing model that applied in actual. power system are compared with some actual arcing wave gained from the field test and show the availability to application of relay test.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.274-276
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• 2005

This paper present an effective modeling scheme of SPE cell system for hydrogen production. As oxygen and hydrogen produced by water electrolysis using SPE are high purity, we can use oxygen in biomedical and hydrogen could be used in many ways. Recently, it is under the eye as a surplus power storage system. PSCAD/EMTDC model of SPE cell system for hydrogen production to efficiently utilize solar cell energy is showed in this paper. The simulated results are then verified by comparing them with the actual values obtained from the data acquisition system. Authors are sure that it is a useful method to the researchers who study SPE cell system for hydrogen production.