• Title/Summary/Keyword: distribution systems

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Economic Evaluations of The Alternatives to Increase the Supply Capacity For Large Customers In The Distribution Systems (대용량 배전계통 공급용량 증대방안에 대한 경제성 분석)

  • Park, Yong-Gi;Roh, Jae-Hyung;Park, Jong-Bae;Choi, Myeon-Song;Kim, Gwang-Won;Kim, Ju-Seong
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.3
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    • pp.500-508
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    • 2011
  • In the distribution systems, the maximum power transportation capacity is restricted within 40MW based on two lines, because of the thermal current limit of a distribution line. Recently it has been continuously required to expand the abilities of the power transportation in distribution systems, as the number of large scale industrial complexes and distributed generations are growing. In this paper, we suggested the five alternatives combining two methods, laying the two bundle lines and adding another voltage between the 22.9kV and 154kV in distribution systems. This paper implemented the economic evaluations of proposed alternatives from national and customer perspectives. And then we compare the results with those of 154kV transmission system.

A Basic Study for the Variation of Nodal Demands According to the Low Pressure in Water Distribution Systems (배수관망내 수압부족시 절점수요량의 변화에 대한 기초적 고찰)

  • Hyun, In-Hwan;Lee, Sang-Mok;Kim, Young-Hwan;Ahn, Yong-Ho
    • Journal of Korean Society of Water and Wastewater
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    • v.16 no.6
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    • pp.726-732
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    • 2002
  • Pressure drop could happen in the water distribution systems due to pipe breaks or maintenance. The pressure drop causes the water service shutdown and nodal water demands should be reduced in some areas. The conventional analysis method of water distribution systems can not consider the change of nodal water demands caused by these pressure drops. This study is to investigate the variation of nodal water demands according to the nodal water pressure and its effect on the analysis of water distribution systems. For these purpose, one real water service district was selected as a study area. As a result, nodal water demand patterns according to the water pressure could be suggested. Also, we could confirm that the suggested new analysis method for the water distribution systems which considering water pressure drops could be more reliable than the conventional method.

A Review of Strategy to Capture Niche Marketing of HTS Power Distribution Cable

  • Park, Sang-Bong;Nam, Kee-Young;Kim, Dae-Kyeong;Jeong, Seong-Hwan;Ryoo, Hee-Suk
    • KIEE International Transactions on Power Engineering
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    • v.4A no.1
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    • pp.11-17
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    • 2004
  • It becomes difficult and high in cost to construct new ducts and/or tunnels for power cables in domestic areas. This paper presents possible strategy of an HTS distribution cables for distributing electric power in local areas as niche marketing. Reflected were its important distinction such as system configuration, rationale, establishment of strategy and considerably high economical efficiency compared with present underground cables. In this paper, applicable important items by using HTS distribution cables in water pumping powerhouse and distribution substation as example objective regions were reviewed. Based on this, the following items on distribution HTS system are examined. (I)A review of constructing a model system to introduce high temperature superconducting distribution cables to objective areas is presented. (2)The strategy to capture HTS distribution cable in water pumping powerhouse and distribution substation as niche marketing regions were reviewed. (3)In concrete, system configuration, rationale, establishment of strategy and considerably high economical efficiency are reviewed between existing cable and HTS one.

Impact Evaluation of Plug-in Electric Vehicle Loading on Distribution Systems in North America (북미 배전계통에서의 플러그인 전기자동차에 대한 계통영향 평가)

  • Kook, Kyung-Soo;Maitra, Arindam
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.9
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    • pp.2236-2245
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    • 2009
  • This paper proposes the process for evaluating the impact of charging the PHEV(Plug-In Hybrid Electric Vehicle) on the distribution systems, and analyzes the study results employing the actual systems as the PHEV is highly expected to increase in the automobile industries in North America in the near future. Since the charging load of the PHEV directly connected to the distribution systems would consume electric power much more than any other existing electric product of residential customers, the new modeling and process would be required to consider the PHEV in distribution systems planning. The EPRI(Electric Power Research Institute) is collaboratively conducting the impact study of PHEV on the distribution systems with power utilities in North America. This study models distribution systems and the charging load of the PHEV using OpenDSS software, and analyzes the impact of PHEV on the distribution systems by assuming various scenarios with different charging time and PHEV types.

A Study on Lightning Surges in Underground Distribution Systems

  • Jung Chae-Kyun;Kim Sang-Kuk;Lee Jong-Beom
    • KIEE International Transactions on Power Engineering
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    • v.5A no.2
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    • pp.171-176
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    • 2005
  • The effects of surge arresters for the protection of transmission systems against direct lightning strokes have already been reviewed by many researchers. However, their studies have not encompassed underground cable systems. Therefore, in this paper we investigate the 22.9kV combined distribution systems that have arresters and ground wires. In addition, we analyze the overvoltages on underground distribution cable sections when direct lightning strokes contact the overhead ground wire using EMTP. Finally, we discuss the effect of lightning strokes according to the change of cable length and installation of arresters. This study provides insulation coordination methods for reasonable system design in 22.9kV underground distribution cable systems.

Constant DC Capacitor Voltage Control based Strategy for Active Load Balancer in Three-phase Four-wire Distribution Systems

  • Win, Tint Soe;Tanaka, Toshihiko;Hiraki, Eiji;Okamoto, Masayuki;Lee, Seong Ryong
    • Journal of international Conference on Electrical Machines and Systems
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    • v.3 no.2
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    • pp.176-183
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    • 2014
  • Three-phase four-wire distribution systems are used for both three-phase three-wire loads and single-phase two-wire consumer appliances in South Korea, Myanmar and other countries. Unbalanced load conditions frequently occur in these distribution systems. These unbalanced load conditions cause unbalanced voltages for three-phase and single-phase loads, and increase the loss in the distribution transformer. In this paper, we propose constant DC capacitor voltage control based strategy for the active load balancer (ALB) in the three-phase four-wire distribution systems. Constant DC capacitor voltage control is always used in active power line conditioners. The proposed control strategy does not require any computation blocks of the active and reactive currents on the distribution systems. Balanced source-side currents with a unity power factor are obtained without any calculation block of the unbalanced active and reactive components on the load side. The basic principle of the constant DC capacitor voltage control based strategy for the ALB is discussed in detail and then confirmed by both digital computer simulations using PSIM software and prototype experimental model. Simulation and experimental results demonstrate that the proposed control strategy for the ALB can balance the source currents with a unity power factor in the three-phase four-wire distribution systems.

Effect of C Factor Errors on the Analysis of Water Distribution Systems (C계수의 추정오차가 배수관망해석에 미치는 영향)

  • Hyun, In Hwan;Lee, Cheol Kyu
    • Journal of Korean Society of Water and Wastewater
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    • v.13 no.2
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    • pp.23-33
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    • 1999
  • This study is to investigate the effect of C factor errors on the analysis of water distribution systems. For this purpose, an artificial distribution network and a real distribution network were selected as the study networks. Results are as follows. 1. The C factor of a pipe which has small velocity didn't give significant effect on the analysis of a water distribution system. 2. The effect of decreased value of C factors give more influence on the analysis of water distribution systems than that of the increased values. 3. For the C factor calibration, errors of the residual water heads as well as those of the head losses should be considered together. 4. In the analysis of water distribution systems, changes of C factors can give influences only on the nodes which locate behind the pipe. Therefore, this characteristics should be considered in the selection of nodes for the measurement of water heads.

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A Program for Calculation of Harmonic Distribution in Distribution Systems (배전계통의 고조파 분포 계산 프로그램)

  • Kim, Sung-Soo;Kang, Yong-Cheol;Nam, Soon-Ryul;Park, Jong-Keun;Myoung, Sung-Ho;Kang, Young-Seok;Choi, Hyo-Yeol
    • Proceedings of the KIEE Conference
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    • 1996.07b
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    • pp.817-819
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    • 1996
  • This paper presents an algorithm for calculation of harmonic distribution in distribution systems. In distribution systems, most state variables are not given explicitly. To calculate the harmonic distribution in distribution systems, state estimation is necessary. In this paper, power usage and harmonic current injection is estimated for each node from practically available data. The estimating procedure is illustrated by examples.

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Fuzzy-GA Application for Allocation and Operation of Dispersed Generation Systems in Composite Distribution Systems (복합배전계통에서 분산형전원의 설치 및 운영을 위한 Fuzzy-GA 응용)

  • 김규호;이유정;이상봉;유석구
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.52 no.10
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    • pp.584-592
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    • 2003
  • This paper presents a fuzzy-GA method for the allocation and operation of dispersed generator systems(DGs) based on load model in composite distribution systems. Groups of each individual load model consist of residential, industrial, commercial, official and agricultural load. The problem formulation considers an objective to reduce power loss of distribution systems and the constraints such as the number or total capacity of DGs and the deviation of the bus voltage. The main idea of solving fuzzy goal programming is to transform the original objective function and constraints into the equivalent multi-objectives functions with fuzzy sets to evaluate their imprecise nature for the criterion of power loss minimization, the number or total capacity of DGs and the bus voltage deviation, and then solve the problem using genetic algorithm. The method proposed is applied to IEEE 12 bus and 33 bus test systems to demonstrate its effectiveness. .

A Study on the Analytical Approach for Reliability Assessment in Distribution Systems Interconnected with Dispersed Storage and Generation Systems (분산형전원이 도입된 배전계통의 신뢰도평가에 관한 연구)

  • Song, Seok-Hwan;Rho, Dae-Seok;Choi, Jae-Seok;Cha, Jun-Min
    • Proceedings of the KIEE Conference
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    • 2001.11b
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    • pp.286-288
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    • 2001
  • This paper deals with the analytical approach for the reliability assessment in radially operated distribution systems. The existing 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 protection systems in the cafe where the Dispersed Storage and Generation Systems are introduced to distribution systems. And this paper shows the effectiveness of the proposed methods by simulating at the model systems.

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