• Title/Summary/Keyword: Combined point

Search Result 1,037, Processing Time 0.041 seconds

A Study on Overvoltage Reduction Method of Single Point Bonded Section on Combined Transmission Lines (혼합송전선로 편단접지 구간 과전압 저감 방안에 관한 연구)

  • Jung, Chae-Kyun;Kang, Ji-Won;Park, Hung-Sok;Kim, Jin
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.58 no.10
    • /
    • pp.1881-1887
    • /
    • 2009
  • This paper discusses the effects of ECC (Earth Continuity Conductor) for reducing the level of induced sheath overvoltages at the single point bonded section of combined transmission lines which are mixed underground power cable with overhead line in one T/L. In previous papers, the characteristics of ECC on only underground power cable systems were sufficiently analyzed. However, the result of only underground power cable systems are totally different from that of combined transmission lines because ECC is commonly grounded with overhead grounding wire at mesh of cable head. Therefore, in this paper, the installation effects of ECC have been variously analyzed considering the three kinds of fault positions, cable formation of duct and trefoil, spacing between phase conductor and ECC, and the change of overhead transmission line section length on 154kV combined transmission line. Finally, simulation results show that ECC can effectively reduce the induced sheath voltage.

Engineering Elastic-Plastic Fracture Analysis for Semi-Elliptical Surface Cracked Plates Under Combined Bending and Tension (복합하중을 받는 평판에 존재하는 반타원 표면균열의 공학적 탄소성 파괴해석법)

  • Shim, Do-Jun;Kim, Yun-Jae;Choi, Jae-Boong;Kim, Young-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.26 no.6
    • /
    • pp.1127-1134
    • /
    • 2002
  • The present paper provides an engineering J estimation equation for surface cracked plates under combined bending and tension. The proposed equation is based on the reference stress approach, and the most relevant normalising loads to define the reference stress for accurate J estimations are given for surface cracked plates under combined bending and tension. Comparisons with J results from extensive 3-D FE analyses, covering a wide range of crack geometry, plate geometry and loading combination, show overall good agreement not only at the deepest point but also at arbitrary points along the crack front. for pure tension, agreement between the estimated J and the FE results is excellent, even at the surface point. On the other hand, for pure bending and combined bending and tension, the estimated J values become less accurate for locations close to the surface point. Thus the results in this paper will be useful to assess short-term fracture or low cycle fatigue of surface defects in plates under combined bending and tension.

Study on the Discharge Characteristics of Non-point Pollutant Source in the Urban Area of the Youngsan-River Basin (영산강 유역 도시지역의 비점오염원 배출특성에 관한 연구)

  • Jin, Young-Hoon;Park, Sung-Chun
    • Journal of Korean Society on Water Environment
    • /
    • v.22 no.4
    • /
    • pp.605-613
    • /
    • 2006
  • Discharge characteristics of non-point source pollutant and load amount of the discharge in the urban area were investigated in the Pungyeongjeong-stream basin and the Yongbong-stream basin in this present study. The land use of the studied basins were divided into paddy field, industrial complex area, combined sewage system, separate sewer system and point sources discharge. The descriptive statistics on the event mean concentrations (EMCs) of non-point pollutants by the the land use showed in the range of 4.43-32.28 mg/L for BOD and 8.27~56.17 mg/L for COD. The highest concentration was shown from the combined sewage system. The EMC of SS at the paddy field in the Pungyeongjeong-stream basin showed the highest range with the values ~ from 35.76 to 358.86 mg/L, which might have been influenced by a levee construction in the adjacent of the area. The relatively high concentration values of 4.43~32.28 mg/L and 1.617.13 mg/L emerged from TN and TP,respectively, at the discharge points of the both stream basins.

A Study on the Stability Boundaries for Single Layer Latticed Domes under Combined Loads (조합하중을 받는 단층 래티스 돔의 안정경계에 관한 연구)

  • 한상을;이갑수
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2000.04b
    • /
    • pp.85-91
    • /
    • 2000
  • The smallest value of the load when the equilibrium condition becomes to be unstable is defined as the buckling load. The primary objective of this paper is to analyse stability boundaries for star dome under combined loads and is to investigate the iteration diagram under the independent loading parameter In numerical procedure of the geometrically nonlinear problems, Arc Length Method and Newton-Raphson iteration method is used to find accurate critical point(bifurcation point and limit point). In this paper independent loading vector is combined as proportional value and star dome was used as numerical analysis model to find stability boundary among load parameters and many other models as multi-star dome and arches were studied. Through this study we can find the type of buckling mode and the value of buckling load.

  • PDF

Flow Characteristics of Parallel Plane Jets (병렬평면제트의 유동특성)

  • Kim Dong-Keon;Yoon Soon-Hyun
    • Proceedings of the KSME Conference
    • /
    • 2002.08a
    • /
    • pp.823-826
    • /
    • 2002
  • Experiments were conducted to show the characteristics of the flow on unventilated parallel plane jets. Measurements of mean velocity components and turbulent intensities were carried out with a particle image velocimetry. The measurements range of these experiments was Reynolds number of 5300 based on the nozzle width and the cases of nozzle-to-nozzle distance were 4, 6, 8, and 10 times the width of the nozzle. Results show that a recirculation zone with a sub-atmospheric static pressure was bounded by the inner shear layers of the individual jets and the nozzles plate. The positions, where maximum value of mean turbulent intensities and mean turbulent kinetic energy show, were at the same position with the merging point. The spread of jets in the merging region increases more rapidly than that of jets in the converging and the combined region. As nozzle-to-nozzle distances were increased, it was shown that merging and combined lengths were shorter.

  • PDF

A Study on a Fault Location Algorithm Using Wavelet Transform in Combined Transmission Systems (혼합송전계통에서 웨이브렛 변환을 이용한 고장점 탐색 알고리즘에 관한 연구)

  • Jeong, Chae-Gyun;Lee, Jong-Beom;Yun, Yang-Ung
    • The Transactions of the Korean Institute of Electrical Engineers A
    • /
    • v.51 no.5
    • /
    • pp.247-254
    • /
    • 2002
  • This paper describes a fault location algorithm in real combined transmission systems with underground power cable. The algorithm to calculate the fault location was developed using DWT wavelet transform and travelling wave occurred at fault point. And the proposed algorithm is also used the transient signal of one end in stead of the signal information of two ends. On the other hand, in this papers, the method to discriminate fault point between overhead line and cable section is also Proposed. Variety simulations were carried out to verify the accuracy and effectiveness of the proposed algorithm using EMTP/ATFDraw and Matlab. Simulation results show that the proposed method has the excellent ability for discrimination of fault section and fault location in combined transmission systems with power cables.

Analysis of Lighting Overvoltage and Induced Voltage of Neutral Line on the 22.9kV Combined Distribution Line (22.9kV 혼합배전선로의 뇌과전압 해석 및 중성선 유기 전압 해석)

  • Hong, Dong-Suk;Lee, Jong-Beom
    • Proceedings of the KIEE Conference
    • /
    • 2000.07a
    • /
    • pp.510-512
    • /
    • 2000
  • This paper describes the voltage induced at neutral line and the proper location of lightning arrester in combined 22.9 kV class distribution line jointed overhead line and cable each other Modeling is established in ATP Draw to perform simulation. Simulated distribution line at this paper consists of distribution line 4.2km and underground distribution line 2km. Overvoltage and induced voltage are analyzed at several point of combined line. Analysis results was compared to select the best point to install arrester. Such analysis technology will be applied to obtaining capacity and location of arrester in the similar combined distribution line.

  • PDF

Dose-response relationship for annoyance caused by combined noise sources in urban spaces (외부 공간에서 복합소음에 대한 불쾌감 연구)

  • Lee, Pyoung-Jik;You, Jin;Jeong, Choong-Il;Yeon, Jun-Oh;Jeon, Jin-Yong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2008.04a
    • /
    • pp.264-267
    • /
    • 2008
  • Relationship between exposure to combined noise sources and community annoyance have been investigated. Social surveys were conducted in urban spaces near the construction site with road traffics. The question relating to noise annoyance was answered on an 11-point numerical scale and 5-point verbal scale according to ISO 15666. The questionnaire also contained demographic factors, interference with daily activities, health-related symptoms, and noise sensitivity. Noise levels were measured in terms of A-weighted equivalent level ($L_{Aeq}$), and noise mapping technique was applied to predict the noise levels of urban spaces. Synthesis curves for the relationship between noise levels and percentage highly annoyed for combined noise sources were derived, and compared to the curves from a single noise source.

  • PDF

Effect of Combined Silver Spike Point Therapy and Electroacupuncture on Patients with Peripheral Facial Paralysis (말초성안면신경마비(末稍性顔面神經痲痺)에 대한 SSP치료요법과 전침요법의 병행치료 효과)

  • Hwang, Ji-Hye;Lee, Dong-Gun;Lee, Hyun-Jin;Cho, Hyun-Seok;Kim, Kyung-Ho;Kim, Kap-Sung
    • Journal of Acupuncture Research
    • /
    • v.24 no.4
    • /
    • pp.69-80
    • /
    • 2007
  • Objective : This study was designed to evaluate the effect of combined Silver Spike Point Therapy and Electroacupuncture on symptoms with Peripheral Facial Paralysis. Methods: We investigated 112 cases of patients with Peripheral Facial Paralysis. The patients were divided into two groups. Group A and B were both treated with basic oriental medicine treatment including Electroacupunctre and Group B was treated with Silver Spike Point Therapy additionaly. We evaluated the tratment effect of each group by using Gross Grading System of House-Brackmann, Yanagihara's Unweighed Grading System before treatment, after 2weeks and 4weeks treatment and Changing Point -period from onset of Peripheral Facial Paralysis to the day which the change begins to be seen at the face-. Results: 1. In Changing point, two groups showed significant differences. 2. As a results of evaluation by using Gross Grading system of House-Brackmann, Yanagihara's Unweighed Grading System, treatment scores showed significant difference over time in each group. 3. After 4weeks treatment, Group B showed significant difference on Gross Grading system of House-Brackmann, Yanagihara's Unweighed Grading System compared with Group A. 4. After 2weeks and 4weeks treatment, the Improvement Indexes of Group B were higher than those of Group A and statistically significant. And after 2weeks and 4weeks treatment, Ratio of Group B on mean of Improvement Index was 1.47 times and 1.34 times as large as those of Group A. Conclusions : Combined Silver Spike Point Therapy on Peripheral Facial Paralysis was more efficacious than the only use of basic oriental treatment including Electroacupuncture.

  • PDF