• Proceedings of the KAIS Fall Conference
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• 2008.05a
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• pp.87-90
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• 2008

This paper deals with the analytical approach for the reliability assessment in radially operated distribution systems. The approach can estimate the expected reliability performance of distribution systems by a direct assessment of the configuration of the systems using the reliability indexes such as NDP(Non-Delivery Power) and NDE(Non-Delivery Energy). The indexes can consider the number and configuration of the load, but can not consider the characteristics of the load which is the one of the most important factor in the investment cost for the distribution systems. Therefore, This paper presents the new indexes considering the expected interruption cost for the load section and shows the effectiveness by simulating at the model systems.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.176-179
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• 1992

This paper presents results of typical sutdy on lightning overvoltages of underground distribution systems and discusses effective insulation coordination schemes. Typical lightning current and system parameters are used to analyze lightning overvoltage distribution on underground distribution systems by EMTP (Electro-Magnetic Transients Program).

• KIEE International Transactions on Power Engineering
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• v.5A no.2
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• pp.97-102
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• 2005

Voltage sags are the most widespread quality issues affecting distribution systems. This paper describes in some detail the voltage sag characteristics due to different types and locations of fault in a practical low voltage power distribution system encountered in the UK. The results not only give utility engineers very useful information when identifying parts of the system most likely to pose problems for customer equipments, but also assist the facility personnel to make decisions on purchasing power quality mitigation equipment.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.378-380
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• 2003

This paper presents the optimal point for measuring harmonic levels in distribution systems. Harmonic should be measure PCC (Point of Common Coupling), where is extended over distribution systems, but some PCCs are limited for economical and technical reason : for this reason, the harmonic measurement for a real distribution system and computer simulation are performed to find the optimal PCC in this paper.

• Water Engineering Research
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• v.3 no.1
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• pp.63-74
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• 2002

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.3
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• pp.240-248
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• 2014

It is DC power that Output of renewable energy being recently developed and researched. Also, demand of DC power will expect to proliferate due to increase of digital load. Thus, DC distribution system providing high quality of power and reliability has emerged as a new distribution system. If the conventional distribution systems are substituted by proposed DC distribution system, the output of renewable energy can be connected with distribution systems under minimum power conversion. Therefore, in the event of connection with DC load, it can construct an efficient distribution system. In this paper, the integrated parallel operation of power conversion module for DC distribution system is proposed. Also, this paper proposed modularization of power conversion devices for DC distribution system and power control for parallel operation of large capacity system. DC distribution system consists of three power conversion modules such as AC/DC power conversion module 2 set, ESS module 1 set. DC distribution system controls suitable operation depending on the status of the DC power distribution system and load. Integrated operation of these systems is verified by simulation and experiment results.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.208-213
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• 2008

In this study, the policies to support reasonable use and effective distribution of air conditioning systems of ice storage type and natural gas type have been investigated. First, this study focused the current policy to stimulate the distribution of these air conditioning systems. Second, the advantage and disadvantage for the air conditioning systems of each type were evaluated. Finally, several policies are proposed for nationwide rational use of energy resources.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.2042-2048
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• 2014

In medium voltage electrical distribution networks, reforming the loss reduction is important, and in line with this, the issue of system engineering and use of proper equipment Expansion of distribution systems results in higher system losses and poor voltage regulation. Therefore, an efficient and effective distribution system has become more important. So, proper selection of conductors in the distribution system is crucial as it determines the current density and the resistance of the line. Evaluation of aging conductors for losses and costs imposed in addition to the careful planning of technical and economic networks can be identified in the network design. In this paper the use of imperialist competitive algorithm; genetic algorithm; is proposed to optimal branch conductor selection and reconstruction in radial distribution systems planning. The objective is to minimize the overall cost of annual energy losses and depreciation on the cost of conductors to improve productivity given the maximum current carrying capacity and acceptable voltage levels. Simulations are carried out on 69-bus radial distribution network using genetic algorithm approaches to show the accuracy as well as the efficiency of the proposed solution technique.

• Journal of Distribution Science
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• v.18 no.9
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• pp.5-11
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• 2020

Purpose: We sought to investigate the operation status of internal accounting control systems in the distribution and service industries and verify whether investing in internal accounting personnel significantly influences the quality of the companies' financial reporting. Research design, data and methodology: We identified descriptive statistics and performed a univariate analysis. Furthermore, a regression analysis verified the impact of investing in internal accounting personnel on the absolute value of discretionary accruals, a proxy for financial reporting quality. Results: Distribution and service companies allocated a significantly higher number of accountants to their internal accounting control systems than companies in other industries. We also confirmed that the absolute value of discretionary accruals significantly decreased as the average working experience of internal accounting personnel in distribution and service companies, in months, increased. Conclusions: In this study, we confirmed that distribution and service companies are devoting efforts to establishing internal accounting control systems and found that financial reporting quality is more effectively controlled as companies allocate more experienced personnel in their internal accounting control system.

• Journal of the Semiconductor & Display Technology
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• v.13 no.4
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• pp.1-5
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• 2014

The plasma density distribution in between the electrode and lateral wall of a narrow gap CCP was investigated. The plasma density distribution was obtained using single Langmuir probe, having two peaks of density distribution at the center of electrode and at the peripheral area of electrodes. The plasma density distribution was compared with the RF fluctuation of plasma potential taken from capacitive probe. Ionization reactions obtained from numerical analysis using CFD-$ACE^+$ fluid model based code. The peaks in two region for plasma density and voltage fluctuation have similar spatial distribution according to input power. It was found that plasma density distribution between the electrode and the lateral wall is closely related with the local ionization.