• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.6
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• pp.60-67
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• 2014

Power system fault analysis is commonly based on well-known symmetrical component method, which describes power system elements by positive, negative and zero sequence impedance. The majority of fault in transmission lines is unbalanced fault, such as line-to-ground faults, so that both positive and zero sequence impedance is required for fault analysis. When unbalanced fault occurs, zero sequence current flows through earth and ground wires in overhead transmission systems and through cable sheaths and earth in underground transmission systems. Since zero sequence current distribution between cable sheath and earth is dependent on both sheath bondings and grounding configurations, care must be taken to calculate zero sequence impedance of underground cable transmission lines. In this paper, EMTP-based sequence impedance calculation method was described and applied to 345kV cable transmission systems. Calculation results showed that detailed circuit analysis is desirable to avoid possible errors of sequence impedance calculation resulted from various configuration of cable sheath bonding and grounding in underground cable transmission systems.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1938-1940
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• 1996

As transmission systems has been complicated and various, cases of transmission systems which is made up with underground cable line only or overhead transmission line with underground cable line have been increased. When transmission lines with different types of cable, it is more likely to be vulnerable to the surges. This paper analyzed these surge in 154kV transmission line by means of EMTP (Electro Magnetic Transient program).

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.175-177
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• 2002

The use of underground transmission cables has increased continuously in densely inhabited urban and suburban for power transmission. Two or more transmission lines are outgoing from one substation in many cases, and one line comprises twin circuits. In order to meet the increasing do and for electric power, underground tables of two or fore circuits are installed in ducts in parallel for several kilometer in the same route. It, however, has not been known generally that the sheath circulating current is generated in a system where a large number of cables are laid on the same route. Therefore, this paper describes an improved analysis method for sheath circulating current on underground transmission cables using EMTP. Author propose several methods to reduce sheath circulating current. The analysing method and reduction methods for two or more underground cables will be really improved for cable system utility.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.5
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• pp.680-688
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• 2015

Hybrid type combined transmission systems is being operated by AC and DC line at the same space will be expanded instead of the overhead line. However, such hybrid type combined system has problem like the arrangement selection of DC cable for effective system operation. In this paper, to select the proper arrangement of DC cable, induced voltage of DC cable influenced by AC cable was analyzed in case of several type arrangement of DC cable. Such induced voltage is in detailed analyzed not only in case of steady, but transient state. The arrangement which has the lowest induced voltage is selected as the proper one. EMTP/ATPDraw is used for modeling and analysis of hybrid type combined transmission system.

• Structural Monitoring and Maintenance
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• v.5 no.1
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• pp.151-171
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• 2018

Transmission tower-line systems are commonly slender and generally possess a small stiffness and low structural damping. They are prone to impulsive excitations induced by cable rupture and may experience strong vibration. Excessive deformation and vibration of a transmission tower-line system subjected to cable rupture may induce a local destruction and even failure event. A little work has yet been carried out to evaluate the performance of transmission tower-line systems in mountain areas subjected to cable rupture. In addition, the control for cable rupture induced vibration of a transmission tower-line system has not been systematically conducted. In this regard, the dynamic response analysis of a transmission tower-line system in mountain areas subjected to cable rupture is conducted. Furthermore, the feasibility of using viscous fluid dampers to suppress the cable rupture-induced vibration is also investigated. The three dimensional (3D) finite element (FE) model of a transmission tower-line system is first established and the mathematical model of a mountain is developed to describe the equivalent scale and configuration of a mountain. The model of a tower-line-mountain system is developed by taking a real transmission tower-line system constructed in China as an example. The mechanical model for the dynamic interaction between the ground and transmission lines is proposed and the mechanical model of a viscous fluid damper is also presented. The equations of motion of the transmission tower-line system subjected to cable rupture without/with viscous fluid dampers are established. The field measurement is carried out to verify the analytical FE model and determine the damping ratios of the example transmission tower-line system. The dynamic analysis of the tower-line system is carried out to investigate structural performance under cable rupture and the validity of the proposed control approach based on viscous fluid dampers is examined. The made observations demonstrate that cable rupture may induce strong structural vibration and the implementation of viscous fluid dampers with optimal parameters can effectively suppress structural responses.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.428-430
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• 2000

This paper describes under-ground transmission cable sheath voltage by using EMTP and proposes a new design method for calculating cable sheath voltage in steady state. The cross bonding system of power cable is modeled on ${\pi}$ equivalent circuit and the sheath voltage(current) of cable can be analyzed with comparing to conventional method.

• Progress in Superconductivity and Cryogenics
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• v.20 no.4
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• pp.60-64
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• 2018

As the offshore wind farms increase, interest in the efficient power system configuration of submarine cables is increasing. Currently, transmission system of the offshore wind farm uses almost AC system. High temperature superconducting (HTS) power cable of the high capacity has long been considered as an enabling technology for power transmission. The HTS cable is a feasible way to increase the transmission capacity of electric power and to provide a substantial reduction in transmission losses and a resultant effect of low CO2 emission. The HTS cable reduces its size and laying sectional area in comparison with a conventional XLPE or OF cable. This is an advantage to reduce its construction cost. In this paper, we discuss the economic feasibility of the 22.9 kV HTS power cable and the conventional AC power cables for an offshore wind farm connections. The 22.9 kV HTS power cable cost for the offshore wind farm connections was calculated based on the capital expenditure and operating expense. The economic feasibility of the HTS power cable and the AC power cables were compared for the offshore wind farm connections. In the case of the offshore wind farm with a capacity of 100 MW and a distance of 3 km to the coast, cost of the 22.9 kV HTS power cable for the offshore wind farm connections was higher than 22.9 kV AC power cable and lower than 70 kV AC power transmission cable.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.5
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• pp.550-557
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• 2008

A transmission control cable connects the transmission control arm and the control lever mechanically and transfers control effort exerted by a driver to the transmission. It also transfers vibration generated by the engine to the passenger room through mechanical connection. To understand vibration and noise transfer mechanism and to further find a way to suppress the transmission of vibration effectively, a dependable dynamic vibration model is a necessity. A vibration model for a transmission control cable is developed and a simulation study has been conducted to obtain mode frequencies and a transmittability. The resonance frequencies obtained by an harmonic analysis is compared with the noise level measurement data. The measurement agrees with the simulation result thus ensures the reliability of the model.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.5
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• pp.445-458
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• 1992

As one of the forced cooling method of the underground power transmission system, external water cooled system with trough in tunnel was investigated. This study is performed on thermal analysis for a standard condition to determine the cable transmission current of the underground power transmission system about the cooling facility. A parametric study was performed for the inlet water temperatures, flow rates, the inlet air velocities, flow rates and the cooling spans. This study shows that the cable transmission current varies within the allowable limitation in compliance with the variation of inlet water temperatures and flow rates. It exhibits little variations for the most intervals in compliance with the variation of inlet air temperatures and flows. But, the cable transmission current fast reduces for a specified interval and consequently affects the underground transmission system. As a result, when the actual forced cooling system is designed, the design conditions of inlet air have to be considered as the most important parameters in determination of the cable transmission current.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.1002-1008
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• 2014

This paper describes insulation design and its reliability evaluation of ${\pm}80kV$ HVDC XLPE cable. Recently, the construction of HVDC transmission system, which is combined overhead line with underground cable, has been completed. This system is installed with existing 154 kV AC transmission line on the same tower. In this paper, the lightning transient analysis is firstly reviewed for selection of basic impulse insulation level and nominal insulation thickness. Then the electrical performance tests including load cycle test and superimposed impulse test based on CIGRE TB 496 are performed to evaluate the reliability of newly designed HVDC cable. There is no breakdown for ${\pm}80kV$ HVDC XLPE cable during electrical performance test. Finally, this system is installed in Jeju island based on successful electrical performance test (Type test). After installation tests are also successfully completed.