• The Journal of the Korea institute of electronic communication sciences
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• v.2 no.1
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• pp.40-45
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• 2007

The repeaterless system can be designed by applying EDFA technology in receiver, transmitter and optical cable in the case of connecting several hundred km from coast to coast, between continents or islands. Because of no repeater the repeaterless system do not need power system to feed laser diode in repeater for signal amplification and cooper tuber in submarine cable. So we can be configured more reliable and economical compared to repeater system. But lower loss optical fiber must be used to get enough signal amplitude without the amplification of repeater. This report consider long distance optical repeaterless system by reflecting the limitation factor of optical amplification.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.6
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• pp.609-616
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• 2011

In the study, we analyzed the collision characteristics of a so-called arch-type submarine cable protector by considering the changes in drop heights of a stock anchor and material models for concrete and steel reinforcing bars. We considered plastic kinematics model and Johnson-Holmquist Concrete model for the concrete and linear elastic model and plastic kinematics model for the reinforcing bars. The drop heights of 2-ton stock anchor were selected as 3, 5, and 8.83m, respectively. ANSYS, a finite element analysis program, was used for the collision analysis. To save computational time, we converted those drop heights into initial velocities by the principle of energy conservation. From the sensitivity of the material models on the drop height changes, it is shown that the collision response of the reinforcing bars is sensitive firstly on the steel models and secondly on the concrete models, while the collision response of the concrete is sensitive only on the concrete models.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.188-189
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• 2006

ITVDC 해저케이블의 절연은 주로 지절연물(紙絶緣物)에 고점도의 컴파운드를 강제함침(mass-impregnation)하여 제조된다. 이러한 강제 함침 작업은 제조 공정 중 가장 긴 시간이 소요되며, 케이블의 절연 특성을 결정하는 중요한 요소가 된다. 그러나 함침은 복잡한 물리현상이며, 함침이 진행되는 동안 케이블의 내부 상태를 직접 관찰하기 곤란하다. 따라서 기존의 제조 경험을 바탕으로 작업조건에 충분한 안전율을 적용하는 실정이다. 이와 같은 강제함침 작업조건을 합리화하면 공정에 소요되는 시간뿐 아니라 함침조건을 조정하여 케이블 절연 특성의 향상까지 기대할 수 있다. 본 논문에서는 당사가 HVDC 해저케이블 개발과정에서 함침에 관한 이론적 검토와 간이 함침실험을 통해 정립한 함침조건에 대해 기술하였다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.1
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• pp.1-7
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• 2013

Structural design and analysis of a coiling arm unloading machine for submarine cable have been originally conducted in this study. Three-dimensional CAD modeling process is practically applied for the structural design in detail. Finite element method(FEM) and multi-body dynamics(MBD) analyses are also used to verify the safety and required motions of the designed coiling arm structure. The effective moving functions of the designed coiling arm with respect to rotational and radial motions are achieved by adopting bearing-roller mechanical parts and hydraulic system. Critical design loading conditions due to its self weight, carrying cables, offshore wind, and hydraulic system over operation conditions are considered for the present structural analyses. In addition, possible inclined ground conditions for the installation of the designed coiling arm are also considered to verify overturn stability. The present hydraulic type coiling arm system is originally designed and developed in this study. The developed coiling arm has been installed at a harbor, successfully tested its operational functions, and finished practical unloading mission of the submarine cable.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.748-749
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• 2007

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, jointing methode of HVDC cable is needed urgently to upgrade current HVDC underwater cable repair technique in Korea to minimize the cost and time factors.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.369_370
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• 2009

This paper describes the fault location method for HVDC submarine cables. Most conventional fault location methods can be applied in off-line. However, in this paper, on-line fault location algorithm is proposed using multi-scale correlating of wavelet coefficient and travelling wave. The propagation velocity is measured by field test on Jeju-Heanam submarine cable section. Finally, the fault location algorithm is tested by same system modeling using EMTP/ATP.

• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.91-91
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• 2017

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.3 no.4
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• pp.255-260
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• 1991

A voltage measuring system specified for the voltage fluctuation of the Pusan-Hamada submarine cable is developed by adding circuits of differential amplification and analog-to-digital conversion to a microprocessor-based data logger with a data modem. This system is charaterized by its small size. no power failure. fully unmanned operation. and precise instrumental drift correction. In addition to the cable voltage and current it measures an ambient temperature and a mercury cell voltage in order to calibrate temperature effect and check its long-term stability. The data acquired by this system show that the voltage signal. comprising fast random noises with a constant width of about 0.2V. fluctuates within a range of about 1V and the fluctuation frequency is similar to that of tidal motion. The source voltage of power feeding equipment (PFE) for the cable system seems to be affected when the room temperature changes rapidly.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2015.11a
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• pp.265-269
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• 2015

우리나라 남해안과 제주도, 그리고 일본, 중국, 대만, 홍콩 등에 거미줄 처럼 포설된 해저 케이블에 대하여 선박 등에 의한 훼손 가능성을 사전에 감지 차단하는 시스템.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.7
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• pp.984-991
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• 2015

This paper presents the methodology for optimal design of power grid for offshore wind power plant (OWPP) and optimum location of offshore substation. The proposed optimization process is based on a genetic algorithm, where the objective cost model is composed of investment, power loss, repair, and reliability cost using the net present value during the whole OWPP life cycle. A probability wind power output is modeled to reflect the characteristics of a wind power plant that produces electricity through wind and to calculate the reliability cost called expected energy not supplied. The main objective is to find the minimum cost for grid connection topology by submarine cables which cannot cross each other. Cable crossing was set as a constraint in the optimization algorithm of grid topology of the wind power plant. On the basis of this method, a case study is conducted to validate the model by simulating a 100-MW OWF.