• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.919-921
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• 1996

Recently, a growing demands on electricity require a high performance and reliable operation in the area of protection, control and monitoring of power plants and substations which may not provides with conventional systems. This paper describes a novel IDPACS (Integrated Digital Protection And Control System) in which we integrate all protection, control and monitoring function of the substations. The simulation results show that the proposed system provides fast response and reliable operation of power plant with superb performance on protection and control system.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.06a
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• pp.143-158
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• 1997

Electrochemical deionization (EDI) offers continuous demineralization at higher water recovery rates (>90%), compared with mixed bed ion exchange, and without the use of chemical regenerants and the associated production of saline waste water. Although EDI technology has been used in some power generation applications, its wider application requires the satisfactory resolution of outstanding capital cost and performance issues. This paper reports on the field evaluation of a new cost-effective EDI technology in a power generation application. The E-Cell System$^{TM}$, which became commercially available in the fourth quarter of 1996, consists of a rugged, modular system, based on a new high-performance EDI stack. Starting in May 1996, a 100 gpm modular EDI pilot system, rated for operation at 100 psi, was evaluated at the TVA Brown's Ferry Nuclear Plant. The feed consisted of Reverse Osmosis (RO) permeate with a conductivity of 4-7 $\mu$S/cm. The pilot system reliably produced 17.8-18.0 M$\Omega$.cm water under design operating conditions, independent. Silica levels were reduced from ca. 50 ppb to 4 ppb, while TOC levels were reduced from ca. 120 ppb to 30 ppb.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.389-394
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• 2004

A Fuzzy Logic Sliding Mode Control or FLSMC for the uninterruptible power system (UPS) is presented, which is tracking a sinusoidal ac voltage with specified frequency and amplitude. The FLSMC algorithm combines feedforward strategy with the Variable Structure Control (VSC) or Sliding Mode Control (SMC) and fuzzy logic control. The control function is derived to guarantee the existence of a sliding mode. FLSMC has an advantage that the stability of FLSMC can be proved easily in terms of VSC. Furthermore, the rules of the proposed FLSMC are independent of the number of system state variables because the input of the suggested controller is fuzzy quantity sliding surface value. Hence the rules of the proposed FLSMC can be reduced. The simulation results illustrate that the purposed approach gives a significant improvement on the tracking performances. It has the small overshoot in the transient and the smaller chattering in the steady state than the conventional VSC. Moreover, its can achieve the requirements of robustness and can supply a high-quality voltage power source in the presence of plant parameter variations, external load disturbances and nonlinear dynamic interactions.

• KEPCO Journal on Electric Power and Energy
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• v.8 no.2
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• pp.69-72
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• 2022

This paper actually investigates the load on major large-scale buildings in the downtown area, examines the economic feasibility of installing PV and ESS in a microgrid target building, and evaluates whether an electric vehicle capable of V2G through two buildings is effective as an economical analysis program (HOMER) was analyzed using. It is economical to install a mixture of ESS rather than using the whole PV, and it is shown that if there is an electric vehicle using the V2G function of EV, there is an economic effect to replace the PV. So that Incentives and policies are needed to replace a large area of PV and utilize the existing parking lot to lead EV as a resource of the microgrid. Currently, P2X technology that stores power as ESS or converts it to other energy to control when surplus renewable energy occurs in large-capacity solar power plants and wind farms, etc. This is being applied, and efforts are being made to maintain the stability of the system through the management of surplus power, such as replacing thermal energy through a heat pump. Due to the increase in electric vehicles, which were recognized only as a means of transportation, technologies for using electric vehicles are developing. Accordingly, existing gas stations do not only supply traditional chemical fuels, but electricity, and super stations that also produce electricity have appeared. Super Station is a new concept power plant that can produce and store electricity using solar power, ESS, V2G, and P2G. To take advantage of this, research on an urban microgrid that forms an independent system by tying a large building and several buildings together and supplies power through a super station around the microgrid is in full swing.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.2
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• pp.145-151
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• 2010

In this study, an absorption power cycle, which can be used for a low-temperature heat source driven power cycle such as geothermal power generation, was investigated and optimized in terms of power by the simulation method. A steady-state simulation model was adopted to analyze and optimize its performance. Simulations were carried out for the given heat source and sink inlet temperatures, and the given flow rates were based on the typical power plant thermal-capacitance-rate ratio. The cycle performance was evaluated for two independent variables: the ammonia fraction at the separator inlet and the maximum cycle pressure. Results showed that the absorption power cycle can generate electricity up to about 14 kW per 1 kg/s of heat source when the heat source temperature, heat sink temperature, and thermal-capacitance-rate ratio are $100^{\circ}C$, $20^{\circ}C$, and 5, respectively.

• Journal of Navigation and Port Research
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• v.42 no.3
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• pp.167-176
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• 2018

A solar power generation system on single point moored offshore plant has independent power system In order to satisfy the maritime environment and account for the number of sunless days, it is important to supply stable electric power to the systems. For these reasons, solar panels are installed in multiple directions. However, a partial shading effect occurs because the amount of light incident on each panel is different. The generated power by the solar generation system installed on land is affected by the latitude, then it is installed at an angle of 30 to $45^{\circ}$. in the case of Korea. In the case of a solar power generation system installed in a mooring type of marine plant, there is a possibility that the maximum power point is outside of the controllable range due to the partial shading effect. Therefore, a power generation loss occurs. By reducing the light amount difference between both panels, the maximum power point can exist in a range where the MPPT algorithm can track the power. The purpose is so the power generation efficiency can be further increased. In this paper, simulation results show that the highest power generation efficiency is obtained at an installation angle of $20^{\circ}$.

• Journal of People, Plants, and Environment
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• v.22 no.1
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• pp.15-29
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• 2019

The purpose of this study is to investigate the effects of the exhibition displays and events of the Agro-healing Experience Hall in the Agricultural Technology Exhibition 2018 on satisfaction and revisit intention of visitors. A survey was conducted on visitors of the Agro-healing Experience Hall and the responses of 274 visitors excluding 26 cases with inappropriate responses were analyzed. For psychological measurement, the Perceived Restorativeness Scale (PRS), Profile of Mood States (POMS), level of plant gardening experience, satisfaction and loyalty were measured. There was a significant difference among age groups in all four factors of the PRS (repose, fascination, coherence, and legibility). In the case of education level, there was a significant difference in the three factors (repose, fascination, and legibility). In addition, average monthly income showed a significant difference among groups in the two factors (fascination and coherence). As a result of analyzing the mood states of visitors for the exhibition events of the Agro-healing Experience Hall, there was a significant difference among age groups only in the case of vigor (p < .05). As a result of analyzing the correlation between the level of plant gardening activities (3 factors) and PRS (4 factors) in the exhibition events of the Agro-healing Experience Hall, plant preference tendency and plant-related event showed a high positive correlation of 0.5 or more with repose of the PRS factors. A multiple regression analysis was conducted to investigate the effects of the level of plant gardening activities, PRS and POMS on the satisfaction and loyalty of visitors. As a result, it was found that in terms of relative explanatory power over independent variables affecting satisfaction and revisit intention, fascination had the greatest effect, followed by vigor, fatigue, and occupation (company employee). The results of this study suggest that exhibition events of the Agro-healing Experience Hall affect repose, fascination or vigor of visitors, and thus can be used positively to increase satisfaction and revisit intention of visitors.

• Plant Journal
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• v.11 no.1
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• pp.30-38
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• 2015

This study is about whether the new Project Finance scheme called "Asset Backed Short Term Bond(ABSTB)" with Project Finance Guarantee Cover provided by Korean Exim Bank(KEXIM) is an appropriate and valid financing structure, through close examinations on domestic and overseas IPP case studies. This study clearly indicates that (i) the interest rate of ABSTB with KEXIM's Project Finance Guarantee is relatively more competitive than the interest rate of other ABSTB guaranteed by EPC Companies (ii) the lower credit rated EPC companies make higher ROE(Return on Equity) through this financing structure. Lastly, Korean EPC Companies can secure profitability through this innovative financing scheme which will also lead to winning more power plant Contracts and become globally competitive.

• Nuclear Engineering and Technology
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• v.51 no.3
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• pp.702-708
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• 2019

This paper deals with break size estimation of loss of coolant accidents (LOCA) using a nonlinear autoregressive with exogenous inputs (NARX) neural network. Previous studies used static approaches, requiring time-integrated parameters and independent firing algorithms. NARX neural network is able to directly deal with time-dependent signals for dynamic estimation of break sizes in real-time. The case studied is a LOCA in the primary system of Bushehr nuclear power plant (NPP). In this study, number of hidden layers, neurons, feedbacks, inputs, and training duration of transients are selected by performing parametric studies to determine the network architecture with minimum error. The developed NARX neural network is trained by error back propagation algorithm with different break sizes, covering 5% -100% of main coolant pipeline area. This database of LOCA scenarios is developed using RELAP5 thermal-hydraulic code. The results are satisfactory and indicate feasibility of implementing NARX neural network for break size estimation in NPPs. It is able to find a general solution for break size estimation problem in real-time, using a limited number of training data sets. This study has been performed in the framework of a research project, aiming to develop an appropriate accident management support tool for Bushehr NPP.

• Structural Engineering and Mechanics
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• v.63 no.1
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• pp.47-53
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• 2017

The fundamental goal of this study is to minimize the uncertainty of the median fragility curve and to assess the structural vulnerability under earthquake excitation. Bayesian Inference with Markov Chain Monte Carlo (MCMC) simulation has been presented for efficient collapse response assessment of the independent intake water tower. The intake tower is significantly used as a diversion type of the hydropower station for maintaining power plant, reservoir and spillway tunnel. Therefore, the seismic fragility assessment of the intake tower is a pivotal component for estimating total system risk of the reservoir. In this investigation, an asymmetrical independent slender reinforced concrete structure is considered. The Bayesian Inference method provides the flexibility to integrate the prior information of collapse response data with the numerical analysis results. The preliminary information of risk data can be obtained from various sources like experiments, existing studies, and simplified linear dynamic analysis or nonlinear static analysis. The conventional lognormal model is used for plotting the fragility curve using the data from time history simulation and nonlinear static pushover analysis respectively. The Bayesian Inference approach is applied for integrating the data from both analyses with the help of MCMC simulation. The method achieves meaningful improvement of uncertainty associated with the fragility curve, and provides significant statistical and computational efficiency.