• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.7
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• pp.974-981
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• 2012

This paper studied about the measurement method of the instantaneous dynamic load characteristics. this experimental study, we derived the instantaneous washing load characteristics and inertial moment characteristics according to the amount of laundry and water level. Also, this studied about the dynamic driving characteristics simulation method for the prediction of washing performance based on this load characteristics analysis. For this study, the design parameters of the driving motor are obtained by FEM analysis and the experiment. By using theses motor parameters and load characteristics, the instantaneous driving characteristics simulation is accomplished and it is verified with the experimental result of various driving conditions. The results of this paper would be very useful to the prediction of washing mode operation characteristics, and it can be also utilized to the washer motor control algorithm design for the washing performance improvement.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.3 s.168
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• pp.86-92
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• 2005

In this paper a forward-backward can extrusion process are analyzed by using rigid-plastic FEM simulation. FEM simulation is conducted to investigate forming characteristics such as deformation modes fur different process parameters. Design parameters such as thickness ratio, punch angle, friction factor and diameter ratio are selected to study the effect of them on the pattern of material flow. The analysis is focused mainly on the influences of the design factors on deformation pattern in terms of forming load, extruded length ratio and volume ratio. It is known for the simulation that the forming load, the length ratio and the volume ratio increase as the thickness ratio (TR), the wall thickness in forward direction to that in backward direction, decreases. The various punch angles have slight influence on the forming load. length ratio and volume ratio. However friction factor have little effect on the forming characteristics such as the forming load, volume ratio and so on. In addition the forming load increases as diameter ratio (DR), the outer diameter of a can in forward direction to that in backward direction, increases. Furthermore the extruded length ratio is lowest with a certain value of DR=0.85 among diameter ratios. Pressure distribution exerted on the die-material interface is illustrated schematically.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1743-1753
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• 2017

Since there are multiple random variables in the probabilistic load flow (PLF) calculation of distribution system containing distributed generation (DG) and electric vehicle charging load (EVCL), a Monte Carlo method based on composite sampling method is put forward according to the existing simple random sampling Monte Carlo simulation method (SRS-MCSM) to perform probabilistic assessment analysis of voltage quality of distribution system containing DG and EVCL. This method considers not only the randomness of wind speed and light intensity as well as the uncertainty of basic load and EVCL, but also other stochastic disturbances, such as the failure rate of the transmission line. According to the different characteristics of random factors, different sampling methods are applied. Simulation results on IEEE9 bus system and IEEE34 bus system demonstrates the validity, accuracy, rapidity and practicability of the proposed method. In contrast to the SRS-MCSM, the proposed method is of higher computational efficiency and better simulation accuracy. The variation of nodal voltages for distribution system before and after connecting DG and EVCL is compared and analyzed, especially the voltage fluctuation of the grid-connected point of DG and EVCL.

• Journal of the Korean Society of Systems Engineering
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• v.16 no.2
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• pp.1-15
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• 2020

Nuclear power plants in South Korea are operated to cover the baseload demand. Hence they are operated at 100% rated power and do not deploy power tracking control except for startup, shutdown, or during transients. However, as the contribution of renewable energy in the energy mix increases, load follow operation may be needed to cover the imbalance between consumption and production due to the intermittent nature of electricity produced from the conversion of wind or solar energy. Load follow operation may be quite challenging since the operators need to control the axial power distribution and core reactivity while simultaneously conducting the power maneuvering. In this paper, a systems engineering approach for multi-physics load follow simulation of APR1400 is performed. RELAP5/SCDAPSIM/MOD3.4/3DKIN multi-physics package is selected to simulate the Korean Advanced Power Reactor, APR1400, under load follow operation to reflect the impact of feedback signals on the system safety parameters. Furthermore, the systems engineering approach is adopted to identify the requirements, functions, and physical architecture to provide a set of verification and validation activities that guide this project development by linking each requirement to a validation or verification test with predefined success criteria.

• Design & Manufacturing
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• v.18 no.2
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• pp.29-34
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• 2024

This study intends to reduce forming load by adding die rotation to flange-upsetting process. Materials arc formed by the compression and rotational torque which are accrued from rotation of the lower die accompanied by axial compression of the punch. For the theoretic analysis of flange-upsetting process using rotation die, slab method was used. Furthermore, for the verification of the theoretic analysis results, FEM simulation using DEFORM 3D a commercial software was done, and through the model material experiment using Prasticine, the results were compared and reviewed. Flange-upsetting process using rotation die shows reduced forming load compared with process without die rotation and demonstrates uniform distribution of strain. And as for the effect of the reduction of forming load, the less the aspect ratio(h₀/d₀) and the greater friction coefficient, the greater effect is. With increase in die rotation velocity, the effect of forming load reduction also increases little by little, but its effect on forming load reduction is very negligible compared with other forming parameters. Theoretic analysis results and simulation results coincided pretty well. The flange-upsetting process using die rotation are evaluated as useful process that can produce reduction of forming load and uniform strain.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2101-2108
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• 2008

Most of train fires which occur in usual cases do not grow up significantly on a large scale enough to bring about casualties and harmful damages. However, the consequence of some train fire accidents can be devastating disaster so that it would be even recorded in history in unusual cases. Accordingly, such a probability of fire disaster cannot be ignored in aspect of the railway safety assesment. A scale of injury and damage is very difficult to predict and analyze. Because it is depend on various factors, i.e. fire load, burning period, facilities, environment condition, and so on. Thus, a prediction of fire load could be understood as a one methodology to estimate railway safety assesment. The summation method which is one of them is used to evaluate the overall fire load by assuming that sum of heat release rate per unit area or mass of each composite material equals the total. However, since the train fire is classified into a compartment fire in under-ventilation condition. The summation method do not estimate a fire load completely. In this journal, Various methods to predict fire load are introduced and evaluated. Especially the fire simulation tool FDS(Fire Dynamics Simulator)which is based on the CFD(Computational Fluid Dynamics) is introduced, too. Through the FDS simulation, numerical analyses for the fire load and flame spread are performed. Then, these results of the simulation are validated through the comparison study with the experimental data. Then, limitations and approximations including in simulation process are discussed. The future direction of research is proposed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.8
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• pp.419-428
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• 2017

In this study, energy loss due to ventilation load in the dock system was analyzed through simulation. Also, flow generated in the dock system of the warehouse was measured using manufactured measuring devices. Numerical simulation was conducted by simulating the most common picking tasks by examining the actual working environment. Incompressible and unsteady turbulent flows were assumed, and the turbulence model was the k-e standard model. Proper grid was selected through grid dependency test. Measurement was conducted using Honeywell and Vaisala sensors, and flow and temperature inside the warehouse were measured and compared with simulation results to validate simulation. When comparing amount of loss occurring in two hours and amount of loss occurring in 15 minutes, docking time of the former was eight times longer but energy loss was 3.8 times lower. Ventilation load occurring during the initial period after opening docking system accounted for a large proportion of total ventilation load. Also, comparing the load when the dock was closed and the load when the truck was parked, ventilation load was significantly higher than load due to heat conduction from the wall. Therefore, in improving the docking system, it is effective to reduce the gap by improving compatibility of the docking system and truck, rather than wall material.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.184.2-184.2
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• 2010

This study performs modelling and simulation of permanent magnetic synchronous generator wind turbine by using Matlab & Simulink. In simulation, change of wind velocity, change of load, and voltage decrease of infinite bus are performed. Through such simulation, different with wiring system that there is only existing load, this study can confirm problems and voltage changing characteristics, which can occur in distributed electric power that load and electric power is mixed and operated, especially, in interconnecting with wind power generation.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.2
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• pp.166-177
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• 1997

The prime mover performance of on - board Diesel Generator is well characterized by the variation of frequency and the load sharing on parallel running under electric load change. This study is aimed to configure the modeling for performance simulation regarding to DG operation which could be interested for education purpose or system analysis. The modeling had been made on the base of modules such as govenor, prime mover of diesel engine and generator with electric load system, which were then intergrated for total simula¬tion performance. One real model system has been introduced for deciding relating parameters and for the comparison of resulting performance in simulation. The responses from the modelling were confirmed in single and paralell operation, the results of which showed resonable accordance with the real system.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.385-390
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• 2000

This paper deals with the design and simulation of the hybrid power filter to compensate reactive power and harmonic components of nonlinear load. Control target is a 3-phase diode full bridge rectifier with L-R-C nonlinear load, this load is assumed adjustable speed driver(ASD). The hybrid filter consists of a shunt active filter, shunt passive filters and series inductors. Control algorithm is based on instantaneous power compensation theory proposed by H.Akagi and etc. The result from simulation shows the hybrid filter is superior than other filters on the point of compensation performance and low cost. The PSCAD/EMTDC 3.0 is used as simulation tools.