• 제목/요약/키워드: cable equation

검색결과 151건 처리시간 0.02초

22.9kV/50MVA급 고온초전도 전력케이블의 교류손실 (The AC loss of 22.9kV/50MVA High-Tc Superconducting Power Cable)

  • 최석진;이상진;심기덕;조전욱;이수길;양병모;윤형희
    • 한국초전도ㆍ저온공학회논문지
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    • 제11권3호
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    • pp.31-34
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    • 2009
  • An HTS power cable is generally composed of 2 layers for conducting and 1 layer for shielding. For the analysis of AC loss of an HTS power cable, 2-dimensional magnetic field analysis is carried out. The magnetization loss in HTS cable core was calculated, and the transport current loss was obtained from the monoblock equation and the elliptical Norris Equation. And the total AC loss of the cable was expected by the sum of magnetization loss and transport current loss. The variation of ac loss with respect to the gap and uncertain factor between the superconducting tapes was investigated, and the ac loss of 22.9kV/50MVA high-Tc superconducting power cable was calculated. These results well agree with those of experiment.

Stochastic stability control analysis of an inclined stay cable under random and periodic support motion excitations

  • Ying, Z.G.;Ni, Y.Q.;Duan, Y.F.
    • Smart Structures and Systems
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    • 제23권6호
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    • pp.641-651
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    • 2019
  • The stochastic stability control of the parameter-excited vibration of an inclined stay cable with multiple modes coupling under random and periodic combined support disturbances is studied by using the direct eigenvalue analysis approach based on the response moment stability, Floquet theorem, Fourier series and matrix eigenvalue analysis. The differential equation with time-varying parameters for the transverse vibration of the inclined cable with control under random and deterministic support disturbances is derived and converted into the randomly and deterministically parameter-excited multi-degree-of-freedom vibration equations. As the stochastic stability of the parameter-excited vibration is mainly determined by the characteristics of perturbation moment, the differential equation with only deterministic parameters for the perturbation second moment is derived based on the $It{\hat{o}}$ stochastic differential rule. The stochastically and deterministically parameter-excited vibration stability is then determined by the deterministic parameter-varying response moment stability. Based on the Floquet theorem, expanding the periodic parameters of the perturbation moment equation and the periodic component of the characteristic perturbation moment expression into the Fourier series yields the eigenvalue equation which determines the perturbation moment behavior. Thus the stochastic stability of the parameter-excited cable vibration under the random and periodic combined support disturbances is determined directly by the matrix eigenvalues. The direct eigenvalue analysis approach is applicable to the stochastic stability of the control cable with multiple modes coupling under various periodic and/or random support disturbances. Numerical results illustrate that the multiple cable modes need to be considered for the stochastic stability of the parameter-excited cable vibration under the random and periodic support disturbances, and the increase of the control damping rather than control stiffness can greatly enhance the stochastic stability of the parameter-excited cable vibration including the frequency width increase of the periodic disturbance and the critical value increase of the random disturbance amplitude.

Estimation of main cable tension force of suspension bridges based on ambient vibration frequency measurements

  • Wang, Jun;Liu, Weiqing;Wang, Lu;Han, Xiaojian
    • Structural Engineering and Mechanics
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    • 제56권6호
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    • pp.939-957
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    • 2015
  • In this paper, a new approach based on the continuum model is proposed to estimate the main cable tension force of suspension bridges from measured natural frequencies. This approach considered the vertical vibration of a main cable hinged at both towers and supported by an elastic girder and hangers along its entire length. The equation reflected the relationship between vibration frequency and horizontal tension force of a main cable was derived. To avoid to generate the additional cable tension force by sag-extensibility, the analytical solution of characteristic equation for anti-symmetrical vibration mode of the main cable was calculated. Then, the estimation of main cable tension force was carried out by anti-symmetric characteristic frequency vector. The errors of estimation due to characteristic frequency deviations were investigated through numerical analysis of the main cable of Taizhou Bridge. A field experiment was conducted to verify the proposed approach. Through measuring and analyzing the responses of a main cable of Taizhou Bridge under ambient excitation, the horizontal tension force of the main cable was identified from the first three odd frequencies. It is shown that the estimated results agree well with the designed values. The proposed approach can be used to conduct the long-term health monitoring of suspension bridges.

유한요소법에 의한 초고압 OF 케이블 접속재의 주도해석에 관한 연구 (Study on the Thermal Analysis of Extra-High Voltage OF Cable Accessories using Finite Element Method)

  • 이종범;강동식;강도현;이수현
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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    • pp.211-215
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    • 1989
  • This paper presents the thermal analysis of EHV OF cable accessories using FEM. The governing equation about the temperature in the cable accessories is induced by the energy balance equation. Since the temperature distribution is a function of space and time, the weighted residual method is adopted for FEM formulation. The difference approximation is used to treat the time differential term in the element equation. Automatic mesh generation which save time and labor is introduced for the data input process. It will be expected that the following thermal analysis result will be very useful to cable accessories design.

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트로이선 가설 작업 로봇의 장력 및 이동 제어에 관한 연구 (Hybrid Tension/Mobile Control of working Robot for installed Troy Cable)

  • 홍정표;원태현;김문수;홍순일
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2007년도 하계학술대회 논문집
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    • pp.455-457
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    • 2007
  • The objective of this study is development of a installed working robot for a troy cable with mobile and tension system. In this paper, an approach to designing controllers for dynamic hybrid Tension/Mobile control of a installed robot for a troy wire cable is presented. Mobile control system of robot is designed based on equation of dc motor and motion for moving robot and tension control system is designed based on equation of ac servomotor for generating torque and dynamic equation of a wire cable. The control parameters is determined by simulation in independence operation of two system.

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초전도 케이블의 Quench 특성에 대한 계통안전성 제어방식 (Power System Security Control Method for Quench Characteristic of High-Temperature Superconducting Cable)

  • 이근준;황시돌
    • 조명전기설비학회논문지
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    • 제19권6호
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    • pp.29-35
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    • 2005
  • 본 논문은 고온 초전도 케이블을 전력계통의 송전용량 증대를 위해 적용시켰을 경우, 고장발생시 초전도케이블에서 예상되는 ??????치의 영향에 대해 안전하게 제어할 수 있는 방법을 제시하였다. 접근 방법으로는 초전도케이블의 ??????치 특성을 열평형 방정식으로 모델링하고 그 결과 고장전류에 따른 케이블의 설계 최대 온도상승한계에 도달하는 시간을 산출하여 기존의 보호계전시스템의 차단시간과 비교함으로서 안전성 여부를 판정하였다. ??????치발생 고장시간을 모의하기 위해 초전도케이블용 EMTDC모형을 개발하였으며, 모의 결과 초전도 케이블 계통을 보호할 수 있는 안전성 제어방식이 설계 가능함을 보였다.

지하구 케이블의 연소특성 실험 (Experiments on the Behavior of Underground Utility Cable in Fire)

  • 박승민;김운형;윤명오
    • 한국화재소방학회논문지
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    • 제16권2호
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    • pp.75-80
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    • 2002
  • 지하공동구에 사용되는 케이블의 연소특성 중 열방출량과 연기 유독성 실험을 수행하였다. 열 방출량 실험은 22.9 kv 전력용 케이블을 대상으로 ISO 9705 규격의 공간에서 수행하였으며 유독성가스의 정량적 위험성 평가를 위하여 NES 713(British-Naval Engineering Standard)을 적용하였다. 실험 결과 측정높이 1.2 m를 기준으로 계산한 케이블의 열 방출 율은 60 kW로 예측되었다. 한편, 케이블의 연기유독성을 위한 NES 실험 결과, 인체에 치명적인 CO의 경우 30분 노출시 사망에 이를 수 있고 의식불명상태가 될 수 있는 수준으로 판정되었다

Modeling and Parameter Identification of the Slung Load System of an Unmanned Rotorcraft using a Flexible Cable

  • Lee, Byung-Yoon;Moon, Gun-Hee;Lee, Dong-Yeon;Tahk, Min-Jea;Oh, Hyun-Shik
    • International Journal of Aeronautical and Space Sciences
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    • 제18권2호
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    • pp.365-377
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    • 2017
  • In this paper, we propose a method to identify the parameters of a rotorcraft slung load system using the modal characteristics of a flexible cable. The proposed method estimates the length of the cable and the mass of the payload by means of a frequency analysis. Dynamic equations of the slung load system with the flexible cable are derived using Udwadia-Kalaba equation (UKE) in order to build a simulation program, and the similarity of the simulated slung load movement is verified by comparison with flight test results. Using the computer simulation program, we show that the proposed method works well within various parameter ranges.

연직하중을 받는 케이블의 형상결정을 위한 반복계산법의 개발 (A Study on an Iteration Method for the Determination the Initial shape of the Cable)

  • 계만수;정진환;조현영
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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    • pp.83-90
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    • 2001
  • In the design of cable structures it is necessary to know the initial shape of the cable. The geometrical condition and the equilibrium equation of the cable are needed. Because the equilibrium equation is expressed by the simultaneous equations of second order, it is almost impossible to solve with elimination method. To solve it, we must use iteration method. In this study, the algorithm which can reduce the number of iteration and calculate shape of the cable is developed and compared with measured data through the laboratory test and the results represent good agreements.

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강사장교 거더와 주탑에 하중저항계수설계법의 보-기둥 상관식을 사용한 내하율 산정식 적용 (Application of Proposed Rating Equations using LRFD Beam-Column Interaction Equations for Girders and Towers in Steel Cable-Stayed Bridges)

  • 최동호;유훈;이범수;조선규
    • 한국강구조학회 논문집
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    • 제19권1호
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    • pp.1-13
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    • 2007
  • 강사장교의 거더와 주탑은 축력과 모멘트를 동시에 받는 보-기둥 부재이기 때문에 단일 힘을 고려하는 일반도로교의 내하율 산정식은 강사장교의 거더와 주탑에 적용할 수 없다. 현재, 사장교의 거더와 주탑에 적용 가능한 이론적인 내하율 산정방법은 아직 정립되지 않았다. 본 논문에서는 축력과 모멘트를 동시에 받는 부재의 상관공식을 적용하여 강사장교 거더와 주탑의 내하율을 산정하기 위한 식을 제안하였다. 영향선해석을 수행하여 각 부재에 압축력 최대, 정 및 부모멘트 최대의 경우에 활하중 재하 형태를 결정하였고 각 부재의 내하율 산정절차를 정리하였다. 제안된 내하율 산정방법의 타당성을 검증하기 위하여 실교량 모델인 돌산대교에 대한 적용예를 제시하였다. 일반도로교의 내하율 산정식은 돌산대교 거더와 주탑의 내하율을 과대평가 하였으며, 제안된 내하율 산정식은 축력과 모멘트를 동시에 지지하는 사장교 거더와 주탑의 거동을 적절히 반영하였다.