• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.288-291
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• 2001

In steel plant, load torque of mill driver motor is changed periodically because working state and idle state are repeated and load current of working state is necessarily higher than rated motor current. The over current limiter is one of the basic thermal protection method from over heating. In this paper, we analyzed the structure of over current limiter for motor and motor driver systems, developed over current limiter with same operation and structured warning system of action of over current limiter. As using this warning system, we can avoid abrupt plant stop by over current limiter in mill driver and lessen producing loss by plant stop. The developed warning system of action of over current limiter is exactly inspected by computer simulation md analysis of acquired data.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.11
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• pp.913-921
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• 1989

This paper deals with a pole placement indirect adaptive control algorithm for discrete-time linear plants with arbitrary zeros. The resulting closed-loop control system is shown to be globally stable subject to the assumptions that an external input is persistently exciting and a lower bound on the magnitude of the Sylvester resultant of the plant numerator and denominator polynomials is known. The problem of controllability of the plant estimate in indirect adaptive control is handled by using an extended parameter correction. The validity of the proposed control algorithm is assured through simulation for a second-order plant.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2301-2303
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• 2003

A steam turnine in thermal/nuclear power plant drives generator and maintains it at rated speed using high temperature and high pressure steam energy. After synchronization in parallel with the power system, generator output increases according as the governor, that is the controller, increases steam flow into turbine. By the way, as the steam flow into turbine can not be reduced fast even though the electrical load is lost, the turbine gets into dangerous situation due to the increase of its speed. At this time, the duty of the turbine governor is to limit the speed to its overspeed trip setpoint by stopping the steam flow as soon as possible, the test of which is called load rejection test. It is introduced in this paper for a simulation test of generator load rejection to be implemented on the turbine governor in a 600MW nuclear power plant before its startup.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.258-260
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• 1993

This paper presents an on-line monitoring and control system designed for the automation of a Concrete plant. The system is based on the combined structure composed of a general purpose PLC (Plogrammable Logic Controller) and a personal computer. Simulation results are ahem to illustrate the system operation. Preconstructed rules are applied to the plant data for the diagnosis of the weighing process in the simulation.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1605-1606
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• 2007

An electrical generator in power plant is driven and maintained its speed at rated by steam turbine. By the way, after synchronization in parallel with the power system, as the steam flow into turbine can not be reduced fast even though the electrical load is lost, the turbine gets into dangerous situation due to the increase of its speed. At this time, the duty of the turbine governor is to limit the speed to its overspeed trip set point by stopping the steam flow as soon as possible, the test of which is called load rejection test. It is introduced in this paper for a field simulation test of generator load rejection to be implemented on the turbine governor in a 680MW nuclear power plant before its startup.

• Journal of Ocean Engineering and Technology
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• v.26 no.1
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• pp.17-26
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• 2012

A coupled analysis of a floating crane barge with a crane wire and hanging structure is carried out in thetime domain. The motion analysis of the crane barge is based on the floating multi-body dynamics, and thecrane wire is modeled as a simple spring tension. The hanging structure is assumed to be a rigid body with 3 degree-of-freedom translational motion. In this study, numerical simulations were conducted at three different stages. First, the developed code was validated by comparing the time-domain motion response of a crane barge with the frequency-domain results. Then, a coupled analysis of a crane barge and simple structure hanging by the crane wire was performed using the present scheme. The motion response and wire tension from the present calculations are compared with the results of OrcaFlex. The agreement between the two sets of results isfairly good. Last, lowering simulations in regular and irregular waves were conducted considering buoyancy changes in the hanging structure. The effects of the wave conditions, structure's weight, wire length, and lowering speed on the wire tension are considered.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.1
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• pp.67-74
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• 2014

Most of steam power plants in Korea are using the method of heating the feed water whenever the ambient temperature around the power plant area below $5^{\circ}C$ to prevent freezing water flowing in the pipe in winter time. But this kind of heat supplying system is not useful to save energy. If we take the method that the temperature of the each pipe is controled by direct measure of temperature by attaching sensor on the outside surface of the feed water tubes, then we can expect that a plenty of energy can be saved. In this study, the computer simulation is used to compare the energy consumption loads of both systems. Energy saving rate is calculated for the location of Incheon area in winter season. Four convection heat transfer coefficients for the ambient air and three initial flowing water temperature inside the tube were used. The result shows that the temperature control system using sensor represents more than 95% of energy saving rate in Incheon area. Even in the severe January weather condition, the energy saving rate is almost 75% in two days basis and even 83% in one day basis.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.2
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• pp.121-128
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• 2014

This study aims to develop a simulation bed for the mechanical balance of plants of high temperature fuel cells such as molten carbonate fuel cells. For using fuel cells in transportation, the optimization of the balance of plants should be considered. In this study, the dynamic model of a molten carbonate fuel cell and the model's responses to inlet gas composition, pressure, flow rate, and stack temperature were analyzed. On/off simulation was performed for testing the dynamic model's feasibility. The simulation results are in reasonable agreement with the experimental results from published literatures.

• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.1-11
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• 2007

Using strong cation exchange simulated moving bed (SMB) chromatography, a nitrogen-phosphate-potassium (NPK) fertilizer is produced in a cost-effective manner. The SMB process operated in a non-traditional way is divided into production and regeneration sections for exclusion of undesirable ions, and composed of six zones including two wash-water zones. This paper addresses modeling and simulation studies on the ion-exchange SMB process, comparing simulation results with experimental data obtained both from a pilot plant and an industrial plant. The simulation results show a good agreement with in situ experimental data obtained in the two plants. The model equation validated by the experiments will be applicable for optimization problems to obtain optimum operating conditions of the process.

• Journal of Biosystems Engineering
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• v.34 no.5
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• pp.342-350
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• 2009

Currently TMR feed produced in commercial plant is one of the major source to feed cattle for both beef and dairy farm. However, because of lack of cutting and mixing system for utilizing domestic produced firmly baled round roughage in commercial TMR plant, these commercial TMR feed can not satisfy to farmers both in quality and price points of view. In order to solve these problems, a farm group size TMR plant model was developed in this study. The model plant was consist of round bale receiving and cutting system, pneumatic conveying system for transfer the roughage which was cut at the cutter to TMR mixer through pneumatic conveyor, TMR mixer enable to soften the stiff rice strew and to mix with other ingredients, finished feed bin which can be transfer to either packing system or individual farm, packing system by tycon bag which contains 400 kg unit and bulk unloading system to individual farmer. Also, a simulation model ARENA was applied to the model system in order to evaluate and check the production rate in each unit process and operation rate of total system and to find out if there are any clogged unit system obstructing the smooth flow of the total process flow. Processing cycle for produce one batch of the model plant was less than 30 minutes. Thus, it will take less than four hours for producing 16 tons per day equivalent to 1,000 beef cattle's daily feed.