• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.210-217
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• 2004

Developed is the new program that the reliability analysis can be performed more effectively considering the correlation of structural members about the cable stayed bridge. This program is formulated the stochastic finite element method suitable for the reliability analysis and the new safety evaluation method is proposed which is different from the existing one by the deterministic method or MCS response analysis. After conducting the initial equilibrium analysis of cable stayed bridges, the stochastic finite element is formulated through the perturbation method and the reliability analysis considering the correlation of stochastic variables is conducted. The results in various types of cable stayed bridge show that the probability of failure considering the correlation is larger than the non-correlation. The fan system is more stable than other systems at the structural response and the probability failure.

• Structural Engineering and Mechanics
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• v.22 no.2
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• pp.197-222
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• 2006

In this paper, the non-linear time-dependent closed-form, discrete and combined solutions for the post-elastic response of a geometrically and physically non-linear suspended cable to a uniformly distributed load considering the creep effects, are presented. The time-dependent closed-form method for the particularly straightforward determination of a vertical uniformly distributed load applied over the entire span of a cable and the accompanying deflection at time t corresponding to the elastic limit and/or to the elastic region, post-elastic and failure range of a suspended cable is described. The actual stress-strain properties of steel cables as well as creep of cables and their rheological characteristics are considered. In this solution, applying the Irvine's theory, the direct use of experimental data, such as the actual stress-strain and strain-time properties of high-strength steel cables, is implemented. The results obtained by the closed-form solution, i.e., a load corresponding to the elastic limit, post-elastic and failure range at time t, enable the direct use in the discrete non-linear time-dependent post-elastic analysis of a suspended cable. This initial value of load is necessary for the non-linear time-dependent elastic and post-elastic discrete analysis, concerning incremental and iterative solution strategies with tangent modulus concept. At each time step, the suspended cable is analyzed under the applied load and imposed deformations originated due to creep. This combined time-dependent approach, based on the closed-form solution and on the FEM, allows a prediction of the required load that occurs in the post-elastic region. The application of the described methods and derived equations is illustrated by numerical examples.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.271-273
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• 1991

We have developed 154kV XLPE (Cross-linked Poly-ethylene) Cable accessories which show excellent performances. The results obtained from experiments using miniature model justified our electrical design and adopted materials, and assembly tests verified higher reliability of these accessories. Basic concepts of design and test, test results and failure analysis are presented.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.15-17
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• 2005

The protection of underground cables against transient overvoltages resulting from lightning and other causes is important in cable-line which is connected with overhead line and underground cable. This paper investigates the failure of SVL(Sheath Voltage Limiter) and presents the application of protection methods for single point bonding on underground transmission cable system. EMTP(Electromagnetic Transient Program) is used in order to study the overvoltages and modeling of components of the system such as, underground cables, SVLs and towers.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.151-158
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• 2000

Cable dome that consists of three component such as cable, strut and fabric membrane has complex structural characteristics. Main structural system of cable dome is cable-strut tensegric system and fabric membrane element is conceived as cladding roof material. One of the important problem of cable dome is to investigate the structural response from external load effect such as snow and wind. When cable dome is subjected to load each structural component has various special structural characteristics. One is that geometrical nonlinearity should be considered because large deformation is occurred from their flexible characteristic. The other is that wrinkling occurs occasionally because cable and membrane elements can not transmit compressive forces. So this paper researches the physical structural response of cable dome structure and the structural behavior when failure occurred at a part of structure.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1996.11a
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• pp.122-124
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• 1996

This paper describes a diagnosis of distribution cable splices by analysis of ultrasonic signals which are generated by partial discharge. A method of ultrasonic signal was used to detect internal defects in distribution cable splices. It is possible that analysis of ultrasonic signal predicts failure by partial discharge generated in distribution cable splices.

• Structural Engineering and Mechanics
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• v.20 no.6
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• pp.609-630
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• 2005

A reliability analysis method is proposed in this paper through a combination of the advantages of the response surface method (RSM), finite element method (FEM), first order reliability method (FORM) and the importance sampling updating method. The accuracy and efficiency of the method is demonstrated through several numerical examples. Then the method is used to estimate the serviceability reliability of cable-stayed bridges. Effects of geometric nonlinearity, randomness in loading, material, and geometry are considered. The example cable-stayed bridge is the Second Nanjing Bridge with a main span length of 628 m built in China. The results show that the cable sag that is part of the geometric nonlinearities of cable-stayed bridges has a major effect on the reliability of cable-stayed bridge. Finally, the most influential random variables on the reliability of cable-stayed bridges are identified by using a sensitivity analysis.

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.95-96
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• 2008

We constructed an on-line PD monitoring system for the 380kV U/G Cable project at the Riyad 9012 substation in Saudi-arabia. The system will be monitoring the termination of the two 380kV XLPE Cables to prevent unexpected failure of the cable insulation. The system had been tested in the laboratory and on-site for detection of various PD signals and reliability of operation. The system distinguish the existence and nonexistence of the partial discharge and then judge the source of partial discharge using automatic PD pattern recognition software.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.2
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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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.229-231
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• 2005

HVDC(High Voltage Direct Current) is an underwater cable between Jeju Island and Haenam in main land and supplies approximately 50% of electrical usage in Jeju Island. If there is any power failure due to HVDC, it will cost approximately 50,000 US dollars per day including Thermal Electrical Generation. Therefore it is absolutely necessary to recover the problem in rapid timely basis. In conclusion, evaluation methode of HVDC cable is needed urgently to upgrade current HVDC underwater cable repair technique in Korea to minimize the cost and time factors.