• 한국구조물진단유지관리공학회 논문집
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• 제12권2호
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• pp.113-120
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• 2008

본 연구는 케이블의 초기길이를 조절하여 케이블 배치가 끝난 후 발생한 장력과 목표장력을 서로 일치시킬 수 있는 초기길이 수정법을 제시하였다. 케이블 지지교량에 대해 정확한 초기길이를 결정하기 위하여 본 연구는 탄성현수선 케이블 요소를 사용하였다. 검증 예제를 해석한 결과 목표장력에 따라 이를 만족하는 초기길이를 결정할 수 있었고 케이블 교량에 대해서도 만족할 만한 결과를 얻을 수 있었다. 따라서 초기길이를 수정하는 본 연구의 방법을 이용하면 목표장력을 도입할 수 있을 것으로 판단된다.

• 전기학회논문지
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• 제65권2호
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• pp.257-263
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• 2016

This paper describes the lightning arrester transients in cable head termination. The installation references of cable head tower and lightning arresters are firstly reviewed, then the performance of lightning arrester operation is also evaluated based on lightning overvoltage analysis by the change of grounding lead cable length. This paper finally proposes the optimal length of grounding lead cable at the cable head termination. The limited lightning current is also proposed according to the change of grounding lead cable length. The results will contribute to protecting insulation breakdown failure against lightning surge at the terminations and joints.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권1호
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• pp.10-14
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• 2001

The superconducting transmission cable is one of interesting part in power application using high temperature superconducting wire. One important parameter in HTS cable design is transport current sharing because it is related with current transmission capacity and loss. In this paper, we calculate self inductances of each layer and mutual inductances between two layers from magnetic field energy, and current sharing of each layer for 4-layer cable using the electric circuit model which contain inductance and resistance (by joint and AC loss). Also, transport current losses which are calculated by monoblock model and Norris equation are compared. As a results, outer layer has always larger transport current than inner layer, and current capacity of each layer is largely influenced by resistance per unit cable length. As a conclusion, for high current uniformity and low AC loss, we have to decrease inductances themselves or those differences.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.183-184
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• 2012

• Journal of Electrical Engineering and Technology
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• 제1권3호
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• pp.308-312
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• 2006

The inductance difference between conducting layers of high-Tc superconducting (HTSC) power transmission cable causes the current sharing of each conducting layer to be unequal, which decreases the current transmission capacity of HTSC power cable. Therefore, the design for even current sharing in HTSC power transmission cable is required. In this paper, we investigated the current distribution of HTSC power cable with a shield layer dependent on the pitch length and the winding direction of each layer. To analyze the effect of the shield layer on the current sharing of the conducting layers of HTSC power cable, the current distribution of HTSC power cable without a shield layer was compared with the case of HTSC power cable with a shield layer. It could be found through the analysis from the computer simulations that the shield layer of HTSC power cable could be contributed to the improvement of current distribution of conducting layers at the specific pitch length and the winding direction of conducting layer. The result and discussion for the current distribution calculated for HTSC power transmission cable with a shield layer were presented and compared with the cable without a shield layer.

• Smart Structures and Systems
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• 제11권4호
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• pp.411-433
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• 2013

Due to its easy operation and wide applicability, the ambient vibration method is commonly adopted to determine the cable force by first identifying the cable frequencies from the vibration signals. With given vibration length and flexural rigidity, an analytical or empirical formula is then used with these cable frequencies to calculate the cable force. It is, however, usually difficult to decide the two required parameters, especially the vibration length due to uncertain boundary constraints. To tackle this problem, a new concept of combining the modal frequencies and mode shape ratios is fully explored in this study for developing an accurate method merely based on ambient vibration measurements. A simply supported beam model with an axial tension is adopted and the effective vibration length of cable is then independently determined based on the mode shape ratios identified from the synchronized measurements. With the effective vibration length obtained and the identified modal frequencies, the cable force and flexural rigidity can then be solved using simple linear regression techniques. The feasibility and accuracy of the proposed method is extensively verified with demonstrative numerical examples and actual applications to different cable-stayed bridges. Furthermore, several important issues in engineering practice such as the number of sensors and selection of modes are also thoroughly investigated.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.825-828
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• 1997

The ferroresonance characteristics in 3 phase transformer is analysed in this paper using EMTP simulations under the consideration of lateral length of the primary cable. The ferroresonant overvoltage or undervoltage may occur in cable-fed 3 phase transformer when single phase switching is made in relatively remote point from the transformer, and this phenomena is closely related to the lateral length of the cable. This paper shows the voltage characteristics concerned with the transformer ferroresonance and the proper lateral length of the cable for reducing the voltage in 3 phase installation, through some case studies.

• 한국구조물진단유지관리공학회 논문집
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• 제9권2호
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• pp.137-146
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• 2005

본 연구는 형상반복법과 수정 라그랑쥐 방법으로 사장교 케이블의 초기장력과 기준길이를 계산하였다. 사장교의 거더와 주탑은 3차원 frame 요소로, 케이블은 비선형 트러스요소와 Ernst의 케이블 요소로 이상화하였다. 본 연구의 유한요소법에 의한 케이블의 초기장력과 실무에서 사용하는 시산법에 의한 케이블의 장력을 비교한 결과, 전자의 경우가 후자의 경우보다 적음을 알 수 있었다. 케이블의 기준길이는 비선형 트러스요소를 사용한 해석결과와 Ernst의 케이블 요소를 사용한 해석결과를 비교하였으며 두 가지 해석결과가 거의 일치함을 알 수 있었다. 또한 기준길이는 초기장력값을 나타내는 단순교의 지간과 거의 일치함을 알 수 있었다. 따라서 케이블의 기준 길이는 본 연구로부터 얻은 초기장력을 가진 단순보의 호의 길이를 나타냄을 알 수 있었다.

• Structural Engineering and Mechanics
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• 제71권3호
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• pp.271-282
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• 2019

The span record of cable-stayed bridges has exceeded 1,000 m, which makes research on the maximum possible span length of cable-stayed bridges an important topic in the engineering community. In this paper, span limit is discussed from two perspectives: the theoretical span limit determined by the strength-to-density ratio of the cable and girder, and the engineering span limit, which depends not only on the strength-to-density ratio of materials but also on the actual loading conditions. Closed form equations of both theoretical and engineering span limits of cable-stayed bridges determined by the cable and girder are derived and a detailed parametric analysis is conducted to assess the engineering span limit under current technical conditions. The results show that the engineering span limit of cable-stayed bridges is about 2,200 m based on materials used available today. The girder is the critical member restricting further increase in the span length; its compressive stress is the limiting factor. Approaches to increasing the engineering span limit are also presented based on the analysis results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1553-1555
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• 1994

In this paper, we describes the research in condenser cone of $SF_6$ gas sealing end for 345KV oil-filled cable. The designed of condenser cone based on the results electric field analysis by electrostatics theory ana FEM. As a results. we have been designed the condenser cone and the inner insulation part of $SF_6$ seating end, the width and length, the number of condenser, the length of stress relief slope, the total length of condenser cone.