• 한국정보전자통신기술학회논문지
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• 제13권6호
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• pp.523-529
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• 2020

배전선로계통의 효율적인 관리와 운영을 위해서 배전지능화시스템은 필수적이다. 배전지능화시스템은 IT를 기반으로 배전망을 통합관리하는 시스템으로 전력산업의 발전과 더불어 진화해 오고 있다. 현재의 배전지능화시스템은 주장치 단위의 독립운전을 기준으로 상대적으로 낮은 네트워크 전송속도로 운영되도록 설계되어있다. 하지만 최근 급속히 보급이 증가하고 있는 태양광이나 에너지 저장장치와 같은 분산자원으로 인하여 미래 배전환경의 운영은 보다 복잡해 지고 있으며 다양한 정보의 실시간 수집이 필요하다. 본 연구에서는 기존의 배전지능화의 한계를 극복하기 위해 차세대 배전지능화 시스템의 요구사항을 도출하였으며, 이를 기반으로 배전계통에 필요한 통신네트워크 체계와 성능요건을 정의하였다. 배전지능화시스템과 같은 대규모 시스템의 현장 도입에는 과도한 시간과 비용이 소요되므로 설계된 시스템의 성능 검증을 위하여 소프트웨어 기반의 단말장치 시뮬레이터를 개발하였다. 시뮬레이터를 활용하여 실제 운영과 유사한 시험환경을 구축하고, 단말장치를 1,000대 까지 증가시켰을 때 제시된 시스템의 네트워크 점유는 최대 10% 이하로 차세대 배전지능화시스템의 기능을 지원하기 위한 네트워크 요구사항을 충족함을 보였다.

• 유통과학연구
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• 제13권6호
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• pp.79-86
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• 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.

• Wind and Structures
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• 제39권1호
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• pp.1-14
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• 2024

Widespread damages from extreme winds have attracted lots of attentions of the resilience assessment of power distribution systems. With many related environmental parameters as well as numerous power infrastructure components, such as poles and wires, the increased challenge of power asset management before, during and after extreme events have to be addressed to prevent possible cascading failures in the power distribution system. Many extreme winds from weather events, such as hurricanes, generate widespread damages in multiple areas such as the economy, social security, and infrastructure management. The livelihoods of residents in the impaired areas are devastated largely due to the paucity of vital utilities, such as electricity. To address the challenge of power grid asset management, power system clustering is needed to partition a complex power system into several stable clusters to prevent the cascading failure from happening. Traditionally, system clustering uses the Binary Decision Diagram (BDD) to derive the clustering result, which is time-consuming and inefficient. Meanwhile, the previous studies considering the weather hazards did not include any detailed weather-related meteorologic parameters which is not appropriate as the heterogeneity of the parameters could largely affect the system performance. Therefore, a fragility-based network hierarchical spectral clustering method is proposed. In the present paper, the fragility curve and surfaces for a power distribution subsystem are obtained first. The fragility of the subsystem under typical failure mechanisms is calculated as a function of wind speed and pole characteristic dimension (diameter or span length). Secondly, the proposed fragility-based hierarchical spectral clustering method (F-HSC) integrates the physics-based fragility analysis into Hierarchical Spectral Clustering (HSC) technique from graph theory to achieve the clustering result for the power distribution system under extreme weather events. From the results of vulnerability analysis, it could be seen that the system performance after clustering is better than before clustering. With the F-HSC method, the impact of the extreme weather events could be considered with topology to cluster different power distribution systems to prevent the system from experiencing power blackouts.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.549-558
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• 2017

DC distribution has several differences compared to AC distribution. DC distribution has a higher efficiency than AC distribution when distributing electricity at the same voltage level. Accordingly, power can be transferred further with low-voltage DC. In addition, power flow in a DC grid system is produced by only a voltage difference in magnitude. Owing to these differences, operation of a DC grid system significantly differs from that of an AC system. In this paper, the power flow problem in a bipolar-type DC grid with unbalanced load conditions is organized and solved. Control strategy of energy storage system on a slow time scale with power references obtained by solving an optimization problem regarding the DC grid is then proposed. The proposed strategy is verified with computer simulations.

• 전기학회논문지
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• 제58권8호
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• pp.1472-1478
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• 2009

The domestic power distribution system is operating in an open loop mode; however, it already has a loop structure. Power distribution systems must be changed for bi-directions power supply for smart networks due to a changing of paradigm in electric power industry. The simplest bi-directions distribution networks can make it closing of normally open switch. However, bi-directions power supply is very difficulty to be operated and there are many parts which it must study. This paper presented various models that are able to change a radial system for loop structures. Further, we compared the reliability index for each model by evaluating the amount of improvement reliability required in radial power distribution system. In addition, we calculated CIC(Customer Interruption Cost) for each model by comparing and analyzing.

• Communications for Statistical Applications and Methods
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• 제15권3호
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• pp.325-332
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• 2008

We consider estimation of reliability P(Y < X) and distribution of the ratio when X and Y are independent uniform random variable and power function random variable, respectively and also consider the estimation problem when X and Y are independent uniform random variable and a half-normal random variable, respectively.

• KIEE International Transactions on Power Engineering
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• 제5A권2호
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• pp.159-170
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• 2005

This paper presents the design and development of a scaled down physical model for power Distribution Automation (DA) system simulation. The developed DA system simulator is useful in providing hands-on experience to utility engineers / managers to familiarize with the DA system and gain confidence in managing the power distribution system from the computer aided distribution control center. The distribution automation system simulator can be effectively used to carry out further research work in this area. This also helps the undergraduate and graduate students to understands the power distribution automation technology in the laboratory environment. The developed DA simulator has become an integral part of a distribution automation lab in the Electrical Engineering Department at Indian Institute of Technology Kanpur in India.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 C
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• pp.1206-1209
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• 1998

For 21th Century, the assignment of power distribution will be the expansion of equipments to supply electric power and harmony with its environment, in process of approving value consciousness of land, space, and the preservation of surroundings. This paper proposes a plan to match with the requirement about equipments, having ability to supply electric power, being harmonized itself with its surroundings by applying a general concept of "Amenity" when we choose an established form of power distribution.

• 한국정보전자통신기술학회논문지
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• 제15권2호
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• pp.95-102
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• 2022

신재생에너지 확대를 위한 배전자동화시스템의 안정성 평가를 위한 연구이다. 정부는 재생에너지 3020 이행계획 정책을 통해 2030년까지 신재생에너지를 확대하여 국민의 삶의 질을 높이는 참여형 에너지 체계로 전환할 계획이다. 정부는 2030년까지 재생에너지 발전량 비중을 국내 보급 에너지의 20%로 목표 설정하였다. 신규 설비용량의 95% 이상을 태양광 풍력 등 청정에너지로 설립할 계획이다. 재생에너지 보급 확대로 에너지 신사업과 분산전원 산업이 육성되어 과거의 대규모 전원 개발이 아닌 근거리, 저압, 소규모 발전이 급속히 확대되었다. 이런 수요로 인해 배전 설비 운영의 중요성이 대두 되었고 배전자동화시스템이 필요성 증대되고 있다. 본 논문에서는 배전자동화시스템의 성능 및 기능 평가를 위한 배전시뮬레이터 개발에 대해 다루었고 이와 배전자동화시스템과의 연동시험 결과를 제시한다. 배전계통에 진보된 시스템을 도입하기 위해서는 송변전시스템의 장점을 취해야 한다. 배전시스템에서 DNP3.0프로토콜을 사용하고 송배전시스템에서 IEC61850 프로토콜을 사용한다. 이 두 프로토콜을 배전자동화시스템에서 혼용하여 사용시 제어, 모니터링 등의 운영에 대한 기능과 성능을 충족한다는 결론을 보였다.

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1305-1309
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• 2013

The application of the superconducting fault current limiter (SFCL) in a power distribution system is expected to contribute the voltage-sag suppression of the bus line as well as the fault-current reduction of the fault line. However, the application effects of the SFCL on the voltage sag of the bus line including the fault current are dependent on its application location in a power distribution system. In this paper, we investigated the fault current limiting and the voltage sag suppressing characteristics of the SFCL due to its application location such as the outgoing point of the feeder, the bus line, the neutral line and the 2nd side of the main transformer in a power distribution system, and analyzed the trace variations of the bus-voltage and fault-feeder current. The simulated power distribution system, which was composed of the universal power source, two transformers with the parallel connection and the impedance load banks connected with the 2nd side of the transformer through the power transmission lines, was constructed and the short-circuit tests for the constructed system were carried out. Through the analysis on the short-circuit tests for the simulated power distribution system with the SFCLs applied into its representative locations, the effects from the SFCL's application on the power distribution system were discussed from the viewpoints of both the suppression of the bus-voltage sag and the reduction of the fault current.