• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.6
• /
• pp.910-915
• /
• 2012

In this paper we propose multi-grounded neutral design method which was considered of transferred transient overvoltage when line to neutral fault occurs. Specially, In order to confirm the actual transient overvoltage magnitude which occurs on neutral line, we considered some screening(shielding) effects. The screening coefficient was deducted from field test results and calculation in a distribution line which is identical with an actual power line. The purpose of this paper is to attempt to suggest the guidance for grounding skystem design considering limitation of overvoltage for LV side in IEC 61936. The result is based on EMTP simulation and real field faults situation in distribution lines.

• Proceedings of the KIPE Conference
• /
• 2010.07a
• /
• pp.468-469
• /
• 2010

DSTATCOM(Distribution STATic COMpensator) is one of the custom power devices, and protects a distribution line from unbalanced and harmonic current caused by non-linear and unbalanced loads. Conventional researches use a LPF(Low Pass Filter) to eliminate ripple component at the calculation of compensation current. This paper proposes a calculation of compensation current using phase shift that can be a counterproposal of conventional methods using LPF.

• Proceedings of the KIEE Conference
• /
• 1995.07b
• /
• pp.588-590
• /
• 1995

This paper presents a new algorithm for the countermeasure to alleviate the line overloads in a power system. This method utilizes network sensitivity factors which are establised from DC load flow solutions. The line outage distribution factors(LODF) are formulated using changes in network power generations to simulate the outaged line from the network. The proposed algorithm has been validated in tests on a 6-bus test system.

• Journal of Distribution Science
• /
• v.13 no.6
• /
• pp.79-86
• /
• 2015

Purpose - The cosmetics industry is a traditional high value-added industry in terms of the domestic demand, small batch production systems, exclusive competition, and raw materials highly dependent on overseas countries as well as an oligopolistic market structure. However, new foreign brands and growing consumer awareness of inexpensive products, has triggered a shift. In line with changing lifestyles and the polarization of consumption, the industry faces a new market structure. Among its key characteristics is the cosmetics industry's numerous distribution channels (i.e., department stores, door-to-door sales, online shopping malls, brand shops, and discount stores). Therefore, the study of its distribution channels is essential. Research design, data, and methodology - The study analyzed channel distribution power divided into coercive and non-coercive power. The factors of coercive power included: unilateral request of an increase in commissions, interference in sales by taking advantage of a superior status, unilateral buck-passing at the time of a problem, unilateral request to stop sales activities, and a unilateral business contract; the factors of non-coercive power included favorable payment conditions, offers of various kinds of information, policy on commission reduction, pride in market entrance, and promotion support. In addition, the mediating variable "interdependence" was applied to the execution of department store (or mart) power and their shop conflicts and satisfaction to examine direct and indirect influential power. The methodology was a survey of managers of cosmetics shops in department stores (or marts). The questionnaire, based on a five-point Likert scale, included questions about basic personal information, execution of power, interdependence, conflict, and satisfaction. The study distributed 198 questionnaires and collected 131. Ten questionnaires with missing or hard to analyze data were excluded. Thus, 121 copies were analyzed. Results - According to the analysis, the execution of coercive power by department stores (or marts) did not affect interdependence, but the execution of non-coercive power did. Interdependence did not influence conflict, but did affect satisfaction. Additionally, the analysis revealed direct influential power: the execution of coercive power positively affected conflict and negatively influenced satisfaction; the execution of non-coercive power positively affected satisfaction. Conclusions - To offer suggestions for distribution business relations in the cosmetics industry, this study investigated how the execution of power by department stores (or marts) affected their shops. More specifically, it examined how much the execution of both coercive power and non-coercive power influenced conflict and satisfaction, and analyzed the mediating role of interdependence. In line with previous study results in various areas, coercive power was shown to be the source of conflict, leading to a decrease in satisfaction, whereas non-coercive power significantly positively influenced satisfaction. Moreover, non-coercive power increased interdependence, which led to greater satisfaction. As a result, interdependence had a mediating effect on non-coercive power and satisfaction. Based on the results, department stores (or marts) should look for improvements plans that increase interdependence. Such plans could alleviate conflict with the shops, increasing their satisfaction.

• Journal of Advanced Marine Engineering and Technology
• /
• v.35 no.7
• /
• pp.966-973
• /
• 2011

Power distribution onboard vessel is typically configured as ungrounded system due to the ability to continuously supply electric power even when an earth fault occurs. The impedance connections between 3 phase power lines and hull cause the line-to-hull voltages to become unstable and increased in case the impedances are unbalanced, bringing the situation susceptible to electric shock and deterioration of insulation material. Also the line-to-hull voltage can reach to a certain maximum value in the steady state depending on the distributed capacitances and grounding resistances between lines and hull. This study suggests how to find and calculate the maximum line-to-hull voltage in view of magnitude and phase angle based on the vector diagram.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.48 no.6
• /
• pp.692-698
• /
• 1999

This paper analyzes the effect of DGS(Dispersed Generation System) on the voltage regulation of the traditional distribution system of which the voltage is controlled by the bank LDC(Line Drop Compensator). Through the simulation results for 22.9kV class distribution system with DGSs, some general relationships among the operating power factor and introduction limit of DGS, and the sending-end reference voltage determined by internal setting coefficients of the LDC are derived. Those relationships are that the introduction limit of DGS increases as the power factor of DGS goes from lagging to leading and also as the allowance of the sending-end reference voltage increases. From the relationships, a operation method of the power distribution system integrated with DGSs is proposed from the view point of the operating power factor of DGS and new voltage regulation method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.21 no.10
• /
• pp.954-960
• /
• 2008

The effects of elastic modulus coefficient and linear expansion coefficient of overhead distribution power line(ACSR $58 mm^2$) on sag behavior in distribution line have been investigated to clarify the difference between specification and experimental level. The elastic modulus coefficients of Al wire and steel wire were $5,182.6 kgf/mm^2,\;18,348.8 kgf/mm^2$, respectively Therefore, the computational composition elastic modulus coefficient of the power line was $7,063.5 kgf/mm^2$, while that of experimentally measured was $7681.1 kgf/mm^2$. As a result, we found that elastic modulus coefficient which was experimentally measured was higher than that of computational by 8.7 %. However, when planner designs the sag of disoibution line, the elastic modulus coefficient of power line $8,400 kgf/mm^2$ should be generally adopted. These two different using values lead to the sag difference of 0.62 m. The other results will be discussed.

• Proceedings of the KIEE Conference
• /
• 1999.07d
• /
• pp.1642-1644
• /
• 1999

This paper provides the results of dielectric properties for aged or controlled lightening arresters. The aged lightening arresters were used for five years in distribution line. The leakage current of lightening arresters and elements was measured to confirm whether the lightening arrester was deteriorated or not. The microstructure was also investigated to determine the size of grain and grain boundary. The dielectric properties of aged lightening arresters were compared to those of controlled lightening arresters. The dielectric constant and the tan${\delta}$ of aged lightening arrester were larger than those of controlled one, resulting from accelerated aging due to the thin grain boundary.

• Proceedings of the KIEE Conference
• /
• 2006.07a
• /
• pp.290-291
• /
• 2006

HTS(High Temperature Superconductivity) Power Cable has a different characteristic with conventional distribution line, so installation and operation condition are different. In this paper, internal fault current characteristic s of HTS power cable was analyzed. For this, EMTDC model component of HTS power cable was developed. The developed EMTDC model component is applied to distribution line, then authors analyze internal current characteristics of HTS Power cable when fault occurred.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2002.11a
• /
• pp.324-327
• /
• 2002

For the characterization of arbitrary shaped printed circuit board, lossy transmission line grid model based on SPICE netlist and analytical plane model based on the segmentation method are proposed in this paper. Two methods are compared with an arbitrary shaped power/ground plane. Furthermore, design considerations for the complete power distribution network structure are discussed to ensure the maximum value of the PDN impedance is low enough across the desired frequency range and to guide decoupling capacitor selection.