• Title/Summary/Keyword: Arrangement of power

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Effect of Reconfiguration and Capacitor Placement on Power Loss Reduction and Voltage Profile Improvement

  • Hosseinnia, Hamed;Farsadi, Murteza
    • Transactions on Electrical and Electronic Materials
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    • v.18 no.6
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    • pp.345-349
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    • 2017
  • Reconfiguration is an important method to minimize power loss and load interruption by creating an optimal configuration of a system. Furthermore, by increasing demand and value of consumption, construction of new power plants can be postponed in networks by reconfiguration and proper arrangement of linkage switches. This method is feasible for radial networks, which create meshes of linkage switches. One convenient way to achieve a system with minimal power loss and interruption is to utilize capacitors. Optimal placement and sizing of capacitors in such applications is an important issue in the literature. In this paper, cat swarm optimization is introduced as a new metaheuristic algorithm to achieve this purpose. Simulation has been carried out in two feasible networks, 69-bus and 33-bus systems.

Wind tunnel study of wake-induced aerodynamics of parallel stay-cables and power conductor cables in a yawed flow

  • Jafari, Mohammad;Sarkar, Partha P.
    • Wind and Structures
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    • v.30 no.6
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    • pp.617-631
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    • 2020
  • Wake-induced aerodynamics of yawed circular cylinders with smooth and grooved surfaces in a tandem arrangement was studied. This pair of cylinders represent sections of stay-cables with smooth surfaces and high-voltage power conductors with grooved surfaces that are vulnerable to flow-induced structural failure. The study provides some insight for a better understanding of wake-induced loads and galloping problem of bundled cables. All experiments in this study were conducted using a pair of stationary section models of circular cylinders in a wind tunnel subjected to uniform and smooth flow. The aerodynamic force coefficients and vortex-shedding frequency of the downstream model were extracted from the surface pressure distribution. For measurement, polished aluminum tubes were used as smooth cables; and hollow tubes with a helically grooved surface were used as power conductors. The aerodynamic properties of the downstream model were captured at wind speeds of about 6-23 m/s (Reynolds number of 5×104 to 2.67×105 for smooth cable and 2×104 to 1.01×105 for grooved cable) and yaw angles ranging from 0° to 45° while the upstream model was fixed at the various spacing between the two model cylinders. The results showed that the Strouhal number of yawed cable is less than the non-yawed case at a given Reynolds number, and its value is smaller than the Strouhal number of a single cable. Additionally, compared to the single smooth cable, it was observed that there was a reduction of drag coefficient of the downstream model, but no change in a drag coefficient of the downstream grooved case in the range of Reynolds number in this study.

A Study on the Overheating of the Power Cable Tray

  • Choi, Hyung-Joo;Lee, Heung-Ho
    • Journal of international Conference on Electrical Machines and Systems
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    • v.2 no.4
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    • pp.413-420
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    • 2013
  • This paper includes the results of the electromagnetic finite element analysis with regard to overheating problem of the power cable tray due to asymmetric magnetic flux density. This phenomenon was experienced in the utility power plant, Korea. The influences of the power cable arrangements and material of the tray were analyzed to find the best solutions using the eddy current-thermal coupled analysis.

Calculation of Reclosing Dead Time of 500 kV Horizontal Single Circuit Transmission Line (500 kV 수평배열 1회선 송전선로의 재폐로 무전압시간 산정)

  • Shim, E.B.;Kwak, J.S.;Joo, H.J.;Park, H.S.;Kang, Y.W.
    • Proceedings of the KIEE Conference
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    • 2005.07a
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    • pp.641-643
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    • 2005
  • It is usual to operate the long transmission line with transposition of each phase in order to avoid voltage unbalance due to unbalanced capacitances at each phase of the line end. This paper described the Ferranti voltage rise of line end, charging current and secondary arc current according to the transposition of line or not. The positive and negative sequence current was derived by the phase current, and then the unbalanced rate was calculated. Then, we obtained the reclosing dead time of the single phase reclosing scheme for 500 kV single circuit horizontal arrangement transmission line system.

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Assessment of Reliability in the Distribution System of an Industrial Complex

  • Choi, Sang-Bong
    • Journal of Electrical Engineering and Technology
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    • v.2 no.2
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    • pp.201-207
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    • 2007
  • As the power industry moves towards open competition, there has been a need for methodology to evaluate distribution power system reliability by using customer interruption costs, particularly in power supply zones under the competitive electricity market. This paper presents an algorithm to evaluate system average interruption duration index, expected energy not supplied, and system outage cost taking into consideration failure rate of the distribution facility and industrial customer interruption cost. Also, to apply this algorithm to evaluate system outage cost presented in this paper, the distribution arrangement of a dual supply system consisting of mostly high voltage customers in an industrial complex in Korea is used as a sample case study. Finally, evaluation results of system interruption cost, system average interruption duration index, and expected energy not supplied in the sample industrial complex area are shown in detail.

Analysis on Attraction Power and Holding Power of Exhibition Areas at Science Museum - Focused on Analysis on Exhibition Method of Exhibition Spaces at Gwacheon National Science Museum - (과학계 박물관 전시공간의 흡입력과 지속력 분석 - 국립과천과학관 전시영역의 연출매체 분석을 중심으로 -)

  • Lim, Che-Zinn;Choo, Sung-Won;Park, Moo-Ho
    • Korean Institute of Interior Design Journal
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    • v.20 no.1
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    • pp.165-172
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    • 2011
  • Visitors' behaviors within an exhibition space are a substantial means to grant spatial arrangement and validity of exhibits. Therefore, the study analyzed visitors' behaviors in the viewpoint of attraction power and holding power of exhibits on the basis of exhibition layout of real science museums. Through the analysis, the study grasped efficiency of analysis index and exhibition environment elements which might have an effect on planning the exhibition space of a large-scale museum and producing detailed ranges of exhibition. The main indicators used are: 1. Attraction power: it indicates the relative incidence of people who have stopped in front of an object/exhibit during the exhibition tour. It is calculated by dividing the number of people who stop by the total number of people who have visited the museum or gallery. 2. Holding power: it measures the average time spent in front of an information/communication element. It is calculated by dividing the average time of stay by the time "necessary" to read an element. As a result, It was expected that attraction power and holding power of exhibit would be increased when moving line of seeing was inductive. However, when the traffic movements of seeing was inductive, repetitive seeing of exhibit was almost never realized and visitors had a strong tendency which viewed on their way of moving without viewing on their way of stopping. On the other hand, it may mean that density of exhibit is low or size of exhibition space is small that most of exhibits within exhibition space have high attraction power and holding power. As Gwacheon National Science Museum, when a museum is composed of many large-scale exhibit halls, it should be formed by separating the main moving line of seeing from the optional moving line of seeing through visitors' natural choice of exhibit and proper inducement of moving line of seeing. In such structure, exhibition environment of the main moving line has an effect on attraction of exhibit and the use of optional moving line acts as a factor to increase attraction. In addition, it is thought that attribute of exhibit and proper arrangement of rest space within exhibition space will increase holding power of exhibit.

Investigations on the Optimum Design of Chemical Addition System for Nuclear Power Plants

  • Chang, Byong-Hoon;Chung, Chang-Kyu;Park, Han-Rim;Kim, Eun-Kee;Ro, Tae-Sun
    • Proceedings of the Korean Nuclear Society Conference
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    • 1997.10a
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    • pp.369-374
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    • 1997
  • Mixing characteristics of tire chemical additives in the chemical injection tank of the chemical and volume control system(CVCS) were investigated for the Yonggwang Nuclear units 5&6. Numerical calculations were performed with a low-Reynolds number turbulence model. Studies were also conducted for the injection tank with a disk located at 1/4H, 2/4H, and 3/4H from the inlet in order to see the effect in the enhancement of chemical mixing. Results show that the optimum arrangement is to locate a disk close to the inlet.

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Study on the insulation of HTS bushing at cryogenic temperature

  • Kim, W.J.;Shin, H.S.;Park, T.S.;Kim, S.H.
    • Progress in Superconductivity and Cryogenics
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    • v.15 no.3
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    • pp.20-23
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    • 2013
  • In the development of high temperature superconducting (HTS) power machines, HTS bushing is one of core technologies. In particular, the insulation body with sheds and electrical insulation at cryogenic temperature have attracted a great deal of interest from the view point of the size, weight and efficiency of bushing. In this study, the electrical and mechanical characteristics of various insulators for body in liquid nitrogen ($LN_2$) were investigated. And the surface discharge distance, collar length of GFRP sheds were studied. To emit bubbles between sheds, the shape and arrangement of shed were studied. The shed structure for 60 kV class HTS bushing were designed with regular arrangement.

Breakdown and Surface Flashover Characteristics of FRP in $LN_2$ (액체질소 중 FRP의 절연파괴 및 연면방전 특성 연구)

  • 정종만;백승명;김상현
    • Progress in Superconductivity and Cryogenics
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    • v.4 no.1
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    • pp.119-123
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    • 2002
  • In this study, we discussed the characteristics of breakdown and surface flashover of FRP in L$N_2$ for applying it to spacer of a superconducting power equipment. Fiberglass reinforced plastic(FRP) has high breakdown puncture strength and has high mechanical strength. So the research of its dielectric properties have been conducted in liquid nitrogen($LN_2$). We measured breakdown voltage of FRP and distinguished four types of surface flashover along solid insulator with arrangement of electrodes and measured the surface flashover voltages of each types of electrode arrangement. The type of a electrode set at the back of the insulator showed the worst dielectric property. The property of surface flashover depending on pressure was tested.

Basic Study on Characteristics of Surface Flashover in L$N_{2}$ (액체질소의 연면 방전 기초 특성 연구)

  • 정종만;백승명;김영석;김상현
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2002.02a
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    • pp.237-240
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    • 2002
  • Fiberglass - reinforced plastic (FRP) can have high breakdown puncture strength and has high mechanical strength. So the research of its dielectric properties have been conducted in liquid nitrogen(L$N_{2}$). In this study, we discussed the characteristics of surface flashover on FRP in L$N_{2}$ for applying it to spacer of a superconducting power equipment. We distinguished four types of surface flashover along solid insulator with arrangement of electrodes and tested the surface flashover voltage of each types of electrode arrangement. The type of a electrode set at the back of the insulator showed the worst dielectric property.

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