• 전기의세계
• /
• 제37권10호
• /
• pp.54-59
• /
• 1988

1968년에 최초로 선진공업국가에서 케이블 열화에 의한 지중 Power Cable의 사고가 발생된 후, utility company는 여러 연구기관과 협력하여 지중배전용 케이블을 수거하여, 케이블의 열화가 계통사고의 원인이 된다는 것을 입증하였다. 또한 고전압 전력계통에 설치된 기존의 OF케이블(oil filled power cable)은 점차로 절연층이 매우 두꺼운 polymer insulated extruded power cable로 대체되어 가는 것이 세계적인 추세이다. 국내에서도 이러한 extruded power cable의 매설이 증가되고 있어, 이에 의한 사고가 발생될 수 있는 potential이 커지고 있기 때문에 우선 전력케이블이 어떠한 이유로 열화되고 어떠한 형태로 나타나는가에 대해 많은 해외연구기관의 연구들을 토대로 간단히 살펴보기로 한다. 열화진단시험방법이나 열화원인분석을 위한 물리화학적 mechanism에 대해서는 다음 기회에 언급하기로 한다.

• 한국전자통신학회논문지
• /
• 제1권1호
• /
• pp.63-69
• /
• 2006

해저광케이블은 육상광케이블에 비해 장거리이며 광중계기 시스템으로 인해 흔히 사용하는 고장지점에서 후방으로 산란 빛으로 거리를 탐지하는 일반적인 OTDR(Optical Time Domain Reflectormeter)의 사용은 매우 제한적이다. 그래서 해저광케이블 시스템에서 광코어의 단선인 경우는 광중계기의 OTDR Path를 이용한 Coherent OTDR를 사용 고장위치 탐지하고, 광신호의 증폭을 위해 광중계기에 필요한 전력을 공급하는 해저광케이블 내의 동튜브(Copper Tube) 손상시에는 전류/전압특성, 단위정전용량등을 이용한 방법들이 사용된다. 이런 정보를 이용하여 해저광케이블의 고장 형태에 따른 적절한 탐지 기법을 제시하고자 한다.

• Structural Engineering and Mechanics
• /
• 제43권5호
• /
• pp.691-709
• /
• 2012

This paper provides a variety of viewpoints to illustrate the mechanism of the deck-stay interaction with the appropriate initial shapes of cable-stayed bridges. Based on the smooth and convergent bridge shapes obtained by the initial shape analysis, the one-element cable system (OECS) and multi-element cable system (MECS) models of the Kao Ping Hsi Bridge in Taiwan are developed to verify the applicability of the analytical model and numerical formulation from the field observations in the authors' previous work. For this purpose, the modal analysis of the two finite element models are conducted to calculate the natural frequency and normalized mode shape of the individual modes of the bridge. The modal coupling assessment is also performed to obtain the generalized mass ratios among the structural components for each mode of the bridge. The findings indicate that the coupled modes are attributed to the frequency loci veering and mode localization when the "pure" deck-tower frequency and the "pure" stay cable frequency approach one another, implying that the mode shapes of such coupled modes are simply different from those of the deck-tower system or stay cables alone. The distribution of the generalized mass ratios between the deck-tower system and stay cables are useful indices for quantitatively assessing the degree of coupling for each mode. These results are demonstrated to fully understand the mechanism of the deck-stay interaction with the appropriate initial shapes of cable-stayed bridges.

• 한국화재조사학회지
• /
• 제7권1호
• /
• pp.83-90
• /
• 2005

To minimize the loss of life and economic about the underground cable fire disaster and ship fire, fabricated with plastics, the government makes effort and regulations. Therefore, the theories, mechanism and environmental effect of the flame retardant was described in this study.

• 한국전자파학회:학술대회논문집
• /
• 한국전자파학회 2000년도 종합학술발표회 논문집 Vol.10 No.1
• /
• pp.272-276
• /
• 2000

본 논문에서는 I/O Cable을 가지는 일반 통신시스템의 전자파 방사 Mechanism을 분석하고, Design에 있어 중요한 Parameter를 도출하였다. 중요한 Design Parameter로 도출된 I/0 Cable의 Coupling mechanism을 실험 및 상용 Software를 이용한 Simulation방법에 의해 분석하고, 이에 대한 EMC Design Rule을 제시하였다. 도출된 EMC Design Rule을 준수하여 Design을 실현하고, 그 효과를 분석하였다. EMC Design Rule에 기반을 둔 개발을 통해 제품의 Redesign및 복잡한 Debug 과정이 없이 효과적으로 전자파 양립성 규격을 만족하였다.

• 한국군사과학기술학회지
• /
• 제4권1호
• /
• pp.52-61
• /
• 2001

The purpose of this paper is to study on the control of a self-activated cable spooling system for towed away handling winch using a hydraulic servo driving unit and a cable position measurement mechanism. To design a controller of the cable spooling system, it is carried out the analysis of the hydraulic servo system and derived the relationship of a parameters through the control theory. Also, it is derived from the control specfications using settling rotation angle and spooling safety ratio proposed to the analysis for the behavior of the system. The cable spooling system is tested and evaluated to validate the performance of the controller.

• 한국공간구조학회:학술대회논문집
• /
• 한국공간구조학회 2005년도 춘계학술발표회 및 정기총회 2권1호(통권2호)
• /
• pp.161-166
• /
• 2005

In spatial structures with large spaces, one important issue in structures with large spaces is how to carry the weight of the roof. A tensegrity cable dome structure is a kind of soft structural system using the tension cable and compression column as a main element. The tensegrity cable dome is built into a variety of shape around the world but then a collapse accident is increasing. Owing to a collapse accident we must grip of the collapse mechanism to prevent an accident and construct the structure with safety and economy. In this study, I investigated the unstable characteristics of the Geiger-type and Flower-type tcnsegrity cable dome structures, which is the lightweight hybrid structures using compression and tension elements continuously, according to the difference of loading conditions.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
• /
• pp.250-250
• /
• 2000

The purpose of this paper is to study on the control of a self-activated cable spooling system for towed array handling winch using a hydraulic servo driving unit and a cable position measurement mechanism. To design a controller of the cable spooling system, it is carried out the analysis of the hydraulic servo system and derived the relationship of a parameters through the control theory. Also, it is derived from the control specifications using settling rotation angle and spooling safety ratio proposed to the analysis for the behavior of the system. The cable spooling system is tested and evaluated to validate the performance of the controller.

• Structural Engineering and Mechanics
• /
• 제15권6호
• /
• pp.653-668
• /
• 2003

Many papers which deal with the dynamic instability of shell-like structures under the STEP load have been published. But, there have been few papers related to the dynamic instability of hybrid cable domes. In this study, the dynamic instability of hybrid cable domes considering geometric nonlinearity is investigated by a numerical method. The characteristic structural behaviour of a cable dome shows a strong nonlinearity, so we determine the shape of a cable dome by applying initial stress and examine the indirect buckling mechanism under dynamic external forces. The dynamic critical loads are determined by the numerical integration of the nonlinear equation of motion, and the indirect buckling is examined by using the phase plane to investigate the occurrence of chaos.

• Wind and Structures
• /
• 제6권1호
• /
• pp.41-52
• /
• 2003

Rain-wind induced vibrations of cables are a challenging problem in the design of cable-stayed bridges. The precise excitation mechanism of the complex interaction between structure, wind and rain is still unknown. A theoretical model that is able to accurately simulate the observed phenomena is not available. This paper presents a mathematical model describing rain-wind induced vibrations as movement-induced vibrations using the quasi-steady strip theory. Both, the vibrations of the cable and the movement of the water rivulet on the cable surface can be described by the model including all geometrical and physical nonlinearities. The analysis using the stability and bifurcation theory shows that the model is capable of simulating the basic phenomena of the vibrations, such as dependence of wind velocity and cable damping. The results agree well with field data and wind tunnel tests. An extensive experimental study is currently performed to calibrate the parameters of the model.