• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.401-403
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• 2001

This paper describes a power flow method for distribution systems, applying the method of symmetrical component to back/forward sweep method. The proposed algorithm is effective for unbalanced radial distribution system, with process of AVR(Auto Voltage Regulator), shunt capacitor. The proposed method was compared with the conventional Back/forward sweep method by using three phase unbalanced distribution systems of 123 nodes.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.11
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• pp.518-524
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• 2005

This paper presents an analytical method for the reliability evaluation of distribution system, including the distributed generations. Unlike the large sized generations of transmission system, the distributed generations have complexities in analyzing and determining the operation. In the process of evaluate reliability, it can be shown that the analytical method is simpler than the Monte-Carlo simulation and the method using Load Duration Curve model is more accurate than that using peak load model. The modeling of distributed generation to analysis distribution system reliability using LDC is proposed in this Paper, and is compared with the MCS method as a result of case studies.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.5
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• pp.34-39
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• 2012

The DAS(Distribution Atomization System) determines a faulted section by using a FI(Fault Indicator) when the fault is occurred on the distribution networks. Sometimes FI is malfunction when the ground fault is occurred on a the distribution networks. As a result difficulties to make decision of faulted section. The cause of the FI malfunction is that the determination using the limited information of the installed area. In this study, a method is proposed to determine faulted section using the amount of the fault current instead of using the FI. This method is determinated faulted section using the fuzzy inference for the collected information from the all switches. The usefulness of the proposed algorithm is verified through the simulation test using PSCAD/EMTDC.

• KIEE International Transactions on Power Engineering
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• v.5A no.3
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• pp.260-268
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• 2005

This paper proposes an improved investment pnonty decision method of facilities considering the reliability of distribution networks. The proposed method decides an investment order of the facilities combining, by fuzzy rules, the investment priority decision by KEPCO and that by reliability evaluation indices. The reliability evaluation indices are SAIFI (System Average Interruption Frequency Index) and SAIDI (System Average Interruption Duration Index). The reliability analysis method of distribution networks applied in this paper utilizes the analytic method, where the used reliability data is the historical data of KEPCO. Particularly, we assumed that the failure rate increases as the equipment ages. To verify the performance of the proposed method, we applied it with the planned projects to reinforce the weak electrical facilities in KEPCO in 2004. The evaluation result showed that, under a limited budget, the reliability of KEPCO in the Busan region using the proposed method could be enhanced if used rather than the conventional method typically in place. Therefore, the results verify that the proposed method can be efficiently used in the actual priorities method for investing in the electrical facilities.

• Journal of the Korean Society of Safety
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• v.33 no.2
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• pp.14-20
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• 2018

In this study, we analyze the current status of major disasters in distribution works and propose safety measures through the distribution live-line work method and electric shock risk assessment. The result of analyzing the ratio of electric shocks to the occurrence of industrial accidents in the recent 13 years shows that the death rate is higher than other industries, especially the construction industry occupying most of the disaster, and it is higher than the collapse disaster. We analyze statistic data of 101 victims selected as core words of live work, distribution line, pole and 22.9 kV in the investigation report of major accident of electric shock fatal from 2001 to 2014. The safety measure was established through the risk assessment of the distribution method using the standard model of the risk assessment based on the results of electric shock analysis on the distribution line. In order to prevent the electric shock accident which is recently being discussed, the risk assessment procedure were carried out in the above-mentioned 22.9kV special high voltage live-line operation method. We derived the risk reduction plan for the distribution line from the results of the major accidents statistic and demonstration of the line works.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.2
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• pp.59-68
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• 1998

This study was conducted to derive optimal design floods by generalized gamma distribution model of the annual maximum series at eight watersheds along Geum, Yeongsan and Seomjin river systems. Design floods obtained by different methods for evaluation of parameters and for plotting positions in the generalized gamma distribution model were compared by the relative mean errors and graphical fit along with 95% confidence limits plotted on gamma probability paper. The results were analyzed and summarized as follows. 1. Basic statistics and parameters were calculated by the generalized gamma distribution model using different methods for parameters. 2. Design floods according to the return periods were obtained by different methods for evaluation of parameters and for plotting positions in the generalized gamma distribution model. 3. It was found that design floods derived by sundry averages method for parameters and Cunnane method for plotting position in the generalized gamma distribution are much closer to those of the observed data in comparison with those obtained by the other methods for parameters and for plotting positions from the viewpoint of relative mean errors. 4. Reliability of design floods derived by sundry averages method in the generalized gamma distribution was acknowledged within 95% confidence interval.

• Tunnel and Underground Space
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• v.15 no.2 s.55
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• pp.137-144
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• 2005

An estimation technique of the joint diameter distribution using the least square method is suggested. When utilizing the technique by Song and Lee, the diameter distribution would be obtained only from the trace length distribution defined in an infinite window after the trace length distribution is estimated from the contained trace length distribution. With the new technique, however, the diameter distribution can be directly obtained from the sample histogram of the contained trace lengths. Compared with the previous technique, it shows a more accurate result for small sizes of joint samples and provides the joint geometry parameter of volumetric frequency. Verification of this new technique was completed by using Monte Carlo simulations.

• Journal of the Semiconductor & Display Technology
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• v.20 no.1
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• pp.18-24
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• 2021

The current settlement and distribution used in theme, background and signal music market other than conventional music is being carried out with either the comprehensive settlement method or the measured meter-rate settlement method in the payment process of collected user fees and compensation depending on the use-permission types. In this settlement and distribution process, however, the reliability issues are often being raised because of the difficulty of tracking rights due to changes in music source rights management information, etc, and the opaque settlement and distribution method itself. This paper proposes a new settlement and distribution platform using a blockchain for the reliable collection and distribution of copyright fees among music user group, monitoring organization group, trust organization group and copyright holders, based on the monitoring information of the theme, background and signal music usage. This platform also provides the transparency in settlement and distribution process among stakeholders through smart contract system.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.922-931
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• 1993

Boundary element method was used to solve heat conduction problem for predicting temperature distribution in grain storage bin. Temperature of grain in storage is one of the three main abiotic factors, besides the intergranular gas composition and the grain moisture content, that determine the keeping quality and control measures used to protect grain from insects and damaging microflora. Collecting the temperature data at various points in the storage bins at different time of the day over a period of time is one way of finding the temperature distribution, this method requires a lot of time, cost and labour and less efficient. However data so collected serve useful purpose of being used to validate predicted temperature distribution using mathematical models. Mathematical models based on physical principles can potentially predict with accuracy the temperature distribution in a grain storage bin. Using the boundary element model the effect of bin wall material, ambient emperature, bin size etc. on temperature distribution can be studied. A knowledge of temperature distribution in stored grain not only helps in identifying active deterioration , but also gives an indication of potential for detection.

• Nuclear Engineering and Technology
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• v.21 no.3
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• pp.193-204
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• 1989

This paper develops a new method for reconstructing neutron flux distribution, that is based on the maximum entropy Principle in information theory. The Probability distribution that maximizes the entropy Provides the most unbiased objective Probability distribution within the known partial information. The partial information are the assembly volume-averaged neutron flux, the surface-averaged neutron fluxes and the surface-averaged neutron currents, that are the results of the nodal calculation. The flux distribution on the boundary of a fuel assembly, which is the boundary condition for the neutron diffusion equation, is transformed into the probability distribution in the entropy expression. The most objective boundary flux distribution is deduced using the results of the nodal calculation by the maximum entropy method. This boundary flux distribution is then used as the boundary condition in a procedure of the imbedded heterogeneous assembly calculation to provide detailed flux distribution. The results of the new method applied to several PWR benchmark problem assemblies show that the reconstruction errors are comparable with those of the form function methods in inner region of the assembly while they are relatively large near the boundary of the assembly. The incorporation of the surface-averaged neutron currents in the constraint information (that is not done in the present study) should provide better results.