• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.12
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• pp.836-842
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• 2011

It has been shown that the air-conditioning system with slab cooling storage is effective in cutting peak load and utilizing nighttime electric power. The stochastic properties of internal heat generation which has great influence on the cooling load are examined in this paper. Based on the measured cooling load and electric power consumption in an office building with slab cooling storage, stochastic time series models to simulate these random processes are investigated. Furthermore, a calculated result by an optimal control method of thermal analysis taking into account the internal heat is compared with the measured cooling load.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.3
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• pp.197-202
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• 1999

Electric arc furnaces (EAFs) use bulk electrical energy to create heat in metal refining industries. The electric arc process is a main cause of the degradation of the electric power quality such as voltage flicker due to the interaction of the high demand currents of the load with the supply system impedance. The stochastic models have described the aperiodic physical phenomena of EAFs. An alternative approach is to include deterministic chaos in the characterization of the arc currents. In this parer, a chaotic approach to such modeling is described and justified. At the same time, a DLL(Dynamic Link Library) module, which is a FORTRAN interface with TACS (Transient Analysis of Control Systems), is developed to implement the chaotic load model in the Electromagnetic Transients Program (EMTP). The details of the module and the results of tests performed on the module to verify the model and to illustrate its capabilities are presented in this paper.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2668-2670
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• 2004

This paper presents an advanced load control method in Direct Load Control(DLC) system. It is important to aggregate a various demand side resource which is surely controllable at the peak power time for a successful DLC system. Because the DLC system use simple On/Off control that may cause a harmful effect on a plant to reduce a peak power load, there are some restriction on deriving a voluntary participation of demand side resource. So it needs a new approach to direct load control method, and this paper describes an advanced load control method using control logic which is based on load properties. This method is easy to take account of a various characteristic of load, it can be use as a dynamic control logic which is good for adaptive control. The suggested control logic method is verified by modeling a control logic for a turbo refrigerator which affects on peak power in summer season.

• Journal of the Korean Society for Railway
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• v.3 no.4
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• pp.219-228
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• 2000

This paper presents an advanced approach to simulate AC electric railway system in steady-state. The algorithm consists of two parts. One is circuit modeling of elements of electric railway system, the other is an analysis on electric circuit. The modeling procedure has two steps, in the first step, proposed is the modeling method which is considered to be an internal impedance of the autotransformers and mutual impedances between the feeding systems. For the load(locomotives) modeling which is the second step, improved results are obtained as application to the proposed constant power model compared with constant impedance model. In the analysis on electric circuit, a generalized analysis method using the loop equation has been proposed and there is no limit in the number of trains between the ATs. In addition, the computer simulation by the proposed model was practiced. Simulation result seems very reasonable. It is therefore concluded that techniques for the electric circuit modeling and analysis have been established. Accuracy of the techniques will be further investigated.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.7
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• pp.327-332
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• 2002

In this paper, conventional reactive power compensation is defined and instantaneous real control concept for shunt converters is proposed. This equipment incorporates the compensation function of harmonics at the distribution line by nonlinear load. These methodologies are applied to IEEE 13 distribution system with the modeling of nonlinear load using EMTEDC/PSCAD package. Simulation with EMTDC results presented to confirm that the new approach has better performance than those obtained by controllers based on traditional concepts of reactive power compensation.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.187-189
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• 1999

Accurate load models allow more precise calculations of power system stability, This paper presents new static voltage stability index considering the load models. Also, We apply the load models for the existent voltage stability indices, and evaluate them.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.7
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• pp.57-66
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• 2009

Microturbines system (MTS) are currently being deployed as small scale on-site distributed generators for microgrids and smart grids. In order to fully exploit DG potentialities, advanced integrated controls that include power electronics facilities, communication technologies and advanced modeling are required. Significant expectations are posed on gas microturbines that can be easily installed in large commercial and public buildings. Modeling, control, simulation of microturbine generator based distributed generation system in smart grid application of buildings for both grid-connected and islanding conditions are presented. It also incorporates modeling and simulation of MT with a speed control system of the MT-permanent magnet synchronous generator to keep the speed constant with load variation. Model and simulations are performed using MATLAB, Simulink and SimPowerSystem software package. The model is built from the dynamics of each part with their interconnections. This simplified model is a useful tool for studying the various operational aspects of MT and is also applicable with building cooling, heating and power (BCHP) systems

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.404-405
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• 2011

In this paper, we present basic modeling of Juju power system using PSCAD/EMTDC. In detail, models of bipolar HVDC system, power transmission line, basic thermal power plant, load, and wind farm have been developed for Jeju power system. For evaluating basic dynamic behavior, we tested the system with a simple scenario and the test result showed acceptable response.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.1
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• pp.6-12
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• 2011

In this study, we proposed a residential load modeling method based on neuro-fuzzy inference system by considering of various harmonics. The developed method was implemented by using harmonic information, fundamental frequency and voltage which are essential input factors in conventional method. Thus, the proposed method makes it possible to effectively estimate load characteristics in power lines with harmonics. To show the effectiveness, the proposed method has been intensively tested with various dataset acquired under the different frequency and voltage and compared it with a conventional method based on neural networks.

• Proceedings of the KIEE Conference
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• summer
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• pp.1352-1354
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• 2004

The accurate analysis on railway traction power system should be carried out a load forecast preferentially. Commonly, it has been performed through Train Performance Simulator (TPS). In the study focused on velocity or location of train, however, the electric power consumption have been computed by converting mechanical power according to given velocity. Therefore, this paper presents a development of a mathematical model for electric load. The proposed load model is expressed as polynomial to reflect the influence of variance of train speed, that is, the model expresses the power as a function of train speed. in this study, method of the least squares method is used to find each coefficient and field test is performed to acquire data, electric power and speed of train in commercial running line.