• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.11
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• pp.1910-1915
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• 2008

The load analysis for the distribution system and facilities has relied on measurement equipment. Moreover, load monitoring incurs huge costs in terms of installation and maintenance. This paper presents a new model to analyze wherein facilities load under a feeder every 15 minutes using meter reading data that can be obtained from a power consumer every 15 minute or a month even without setting up any measuring equipment. After the data warehouse is constructed by interfacing the legacy system required for the load calculation, the relationship between the distribution system and the power consumer is established. Once the load pattern is forecasted by applying clustering and classification algorithm of temporal data mining techniques for the power customer who is not involved in Automatic Meter Reading(AMR), a single-line diagram per feeder is created, and power flow calculation is executed. The calculation result is analyzed using various temporal and spatial analysis methods such as Internet Geographic Information System(GIS), single-line diagram, and Online Analytical Processing (OLAP).

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.460-465
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• 2001

Pollutant load using unit load method is calculated by simply equation, especially, very useful in the area that didn't exist about water quality data. However, it takes long time to calculate pollutant load with area in which there is various pollutants and if the boundary of a basin altered, the work of calculation about pollutant load must be begun from the first again. Therefore, a Total Daily Load Program(TDLP) was developed to calculate pollutant load automatically in rural area. The TDLP includes a geographic information system(GIS), relational database system(RDBS), User Interface. This Program can provide user with creating a boundary of the basin that user is concerned with to satisfy the water quality regulations and calculating daily load for various pollutants. The effort was conducted to apply the developed TDLP to calculating pollutant load in rural basin called Bok-ha river.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.174-177
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• 2003

Cooling load from the top plate to L$N_2$ surface, including wall conduction, gas conduction, radiation, and current leads, is investigated in a closed cooling system for HTS transformer. In general methods of load calculation, individual load is estimated separately, but they are actually coupled each other because of natural convection of nitrogen vapor. Using heat transfer analysis, we calculate cooling load with taking into account the effect of natural convection. Cooling load is under- estimated approximately 2 ％ when the natural convection is ignored. If the operating current is high, there will be a wide difference between actual cooling load and cooling load by individual calculation. Cooling load decreases with increasing number of radiation shield. With production, construction, and cooling load, three radiation shields are proper to 1 MVA HTS transformer.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.6
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• pp.1034-1040
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• 2010

This paper presents a calculation method of the area of severity for the stochastic assessment of voltage sags. In general, the annual expected numbers of voltage sags at an individual load point can be estimated stochastically. However, in order to assess the system voltage sag performance considering many sensitive load points together, it is necessary to determine and analysis the area of severity for the load points. The area of severity to voltage sags is the network region where the fault occurrences will simultaneously lead to voltage sags at different load points. In this paper, the concept of the voltage sag assessment and the calculation method of the area of severity are addressed. The analysis of the area of severity is performed on the IEEE 30-bus test system by using the proposed method. The method is useful for the stochastic assesment of voltage sags and the establishment of systematic plans for voltage sag mitigation.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.4
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• pp.170-178
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• 2001

Deadbeat technique has been proposed as a digital controller for an UPS inverter to achieve the fast, response to a load variation and to conserve a very low THD under a nonlinear load condition. This scheme contains a fatal drawback, sensitivity against parameter variation and calculation time delay. This paper proposes a second order deadbeat controller, which fundamentally solves the calculation time delay problem and certainly guarantees the robustness of the parameter's variation. RLP(Repetitive Load Predictor) which predicts the load current ahead of two sampling time and FVR(Fundamental Voltage Regulator) which eliminates the fundamental errors of the output voltage are also proposed for the second order deadbeat controller to apply to UPS inverter systems. These are shown theoretically and practically through simulation and experiment.

• Earthquakes and Structures
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• v.24 no.5
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• pp.365-375
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• 2023

Energy dissipation systems increase the energy dissipation capacity of buildings considerably. In this study, the effect of dampers on a typical 10-storey reinforced concrete structure with a ductile moment-resisting frame was investigated. In this context, 5 different models were created according to the calculation of the slip load and the positions of the dampers in the structure. Nonlinear time-history analyzes using 11 different earthquake acceleration records were performed on the models using the ETABS program. As a result of the analyses, storey displacements, energy dissipation ratios, drift ratios, storey accelerations, storey shears, and hysteretic curves of the dampers on the first and last storey and overturning moments are presented. In the study, it was determined that friction dampers increased the energy dissipation capacities of all models. In addition, it has been determined that positioning the dampers in the outer region of the structures and taking the base shear as a basis in the slip load calculation will be more effective.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.6
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• pp.340-349
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• 2004

Recently, the needs and concerns for the power loss are increasing according to the energy conservation at the level of the national policies and power utilities's business strategies. Especially, the issue of the power loss is the main factor for the determining the electric pricing rates in the circumstances of the deregulation of electrical industry. However, because of the lacking of management for power loss load factors (LLF), it is difficult to make a calculation for the power loss and to make a decision for the electric rates. And loss factor(k-factor), which is a most important factor for calculation of the distribution power loss, has been used as a fixed value of 0.32 since the fiscal year 1973. Therefore, This study presents the statistical calculation methods of the loss factors classified by load types and seasons by using the practical data of 65 primary feeders which are selected by proper procedures. Based on the above the algorithms and methods, the optimal method of the distribution loss management classified by facilities such as primary feeders, distribution transformers and secondary feeders is presented. The simulation results show the effectiveness and usefulness of the proposed methods.

• KIEE International Transactions on Power Engineering
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• v.5A no.2
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• pp.109-115
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• 2005

Recently, the needs and concerns regarding power loss have been increasing according to energy conservation at the level of the national policies and the business strategies of power utilities. In particular, the issue of power loss is the main factor for determining rates for electrical consumption in the deregulation of the electrical industry. However, because of the lack of management for power loss load factors (LLF) it is difficult to make a calculation for power loss and to make a decision concerning the electric rates. Furthermore, loss factor (k-factor) in Korea, which is of primary significance in the calculation of distribution power loss, has been used as a fixed value of 0.32 since the fiscal year 1973. Therefore, this study presents the statistical calculation methods of the loss factors classified by load types and seasons by using the practical data of 65 primary feeders that have been selected by appropriate procedures. Based on the above, the algorithms and methods, as well as the optimal method of the distribution loss management classified by facilities such as primary feeders, distribution transformers and secondary feeders is presented. The simulation results demonstrate the effectiveness and usefulness of the proposed methods.

• Journal of Applied Reliability
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• v.13 no.4
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• pp.241-252
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• 2013

Because of financial and safety concerns, there are needs for more accurate prediction of bridge behavior. Underestimation of the bridge load carrying capacity can have serious economic consequences, as deficient bridges must be repaired or rehabilitated. Therefore, the knowledge of the actual bridge behavior under live load may lead to a more realistic calculation of the load carrying capacity and eventually this may allow for more bridges to remain in service with or without minor repairs. The presented research is focused on the reliability evaluation of the actual load carrying capacity of existing bridges based on the field testing. Seventeen existing bridges were tested under truck load to confirm their adequacy of reliability. The actual response of existing bridge structures under live load is measured. Reliability analysis is performed on the selected representative bridges designed in accordance with AASHTO codes for bridge component (girder). Bridges are first evaluated based on the code specified values and design resistance. However, after the field testing program, it is possible to apply the experimental results into the bridge reliability evaluation procedures. Therefore, the actual response of bridge structures, including unintentional composite action, partial fixity of supports, and contribution of nonstructural members are considered in the bridge reliability evaluation. The girder distribution factors obtained from the tests are also applied in the reliability calculation. The results indicate that the reliability indices of selected bridges can be significantly increased by reducing uncertainties without sacrificing the safety of structures, by including the result of field measurement data into calculation.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.72-77
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• 2008

About 25% of overall energy use of Korea had been spent in buildings. It is crucial to acknowledge the importance of saving energy in buildings. In order to save energy, it is important to predict accurate energy use. There are numerous energy simulation program that predicts both energy load and energy use. The problem of the energy simulation program is that it holds too many input variables, and it needs experts to model a building. So, our purpose of this study is to develop the simplified thermal load calculation program for building energy analysis which eliminates coordinates of building components instead of using full coordinates by using DOE2. Since the engine of the program is DOE2, we verified the validity of S-DOE by comparing peak heating & cooling load results and annual energy use results. The results shows that there are little difference between VisualDOE and S-DOE. Also it showed that S-DOE took less time to input variables than VisualDOE. These results reveals that the application of S-DOE is possible to accurately predict energy load and energy use of the building and still have strong point that it takes less time to analyse building energy.