• The Journal of the Korea institute of electronic communication sciences
• /
• v.2 no.1
• /
• pp.34-39
• /
• 2007

Submarine cable is the leading means of international communication across oceans. However, when such important submarine cable is damaged, that causes not only huge amount for the repair but also losing the nation's reliability internationally, and has brought about much difficulty and loss due to the interruption of communication. So, in order to deduce methods for the stability of submarine cables, this paper is studying the present status of submarine cables and the causes of cable faults, and suggesting techniques and regulations to protect from the trouble of submarine cables.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2017.05a
• /
• pp.329-329
• /
• 2017

In this study attempted to evaluate the stability of the protection methods by examining hydraulic characteristics of the area around the point in which marine cable protector is installed such as surf zone occurrence point of shore-end submarine cables suitable for coastal marine environmental conditions, flow rate t the tope of the protector and maximum wave height, and to provide basic data for the selection of the optimal protection method. In performing hydraulic model experiments, the topography of submarine cable installation location was reproduced in 2-D sectional channel, and models appropriate for experimental scale and similitude law were produced and installed for each condition of submarine cables and protectors. Since the topography and submarine cable protectors were reproduced and installed in 2-D sectional channel, the exact reproduction of surf and transformation in shallow water zone was possible, and thus the physical properties could be clearly analyzed. For stability review, an experiment to examine the stability was conducted using a wave maker with 50-year frequency design waves as target, and wave height and cycles were applied based on the approximate lowest low water level(Approx. L.L.W), which is the most dangerous in submarine cable protection methods. As for experimental time, typhoon passing time in summer (about 3 hours) was applied, and wave patterns and deviation ratio of the submarine cable protector were investigated after making irregular waves corresponding to design waves. In addition, current meter and wave height meter were installed at the installation location of the submarine cable protector, and the flow rates and wave height at the top of the protector were measured and analyzed to review hydraulic properties.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.359_360
• /
• 2009

KEPCO signed up with LS CABLE as a contractor for HVDC submarine cable construction in February 2009. The desk research has been completed in may 2009. Also, Cable route and the protection method will be selected by November 2009. The tentative cable route between Jindo and Jeju which is consisted of sea farms and shipping route zone will reach almost 105km. The oceanographic survey for the selection of protection method will be carried out and the survey lists are consisted of MBES, SSS, CPT, ADSP. The protection methods such as burial, Concrete Mattress, UP Pipe, Rock Berm will be selected as per each condition of sea area after the oceanographic survey is completed. Kepco has developed variable methods based on the maintenance experience for HVDC submarine cable between HAENAM and JEJU. Based on the such a accumulated know-how, it can be expected for the confidence and stability of the 2nd HVC project to be improved.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.3 no.1
• /
• pp.1-7
• /
• 2008

Submarine cable is the most important IT infrastructure for international communication across oceans. However, a cable fault rarely happens by ship's anchor, fishing gears, submarine earthquake, and so on, and we need to improve on repair time for the reducing expenses of cable repair ship as well as the stability of high-capacity submarine optical network. There are several kinds of cable faults such as Shunt fault, Cable cut, Open fault and Fiber break. When a fault is occurred, cable landing stations(CLS) have to analysis failure quickly and accurately to find the type and the location of a cable fault. During the repair period, CLS should swiftly perform the tests requested by cable repair ship. In order to make rapid progress on cable repair, CLS test technique is very important. So, in order to reduce the repair time, this paper is studying the CLS test techniques of locating a submarine cable fault and of checking the splicing point performed by cable repair ship.

• Proceedings of the KIEE Conference
• /
• 2002.07a
• /
• pp.557-559
• /
• 2002

KEPCO has been operating since March 1998 a HVDC link between Cheju Island and the mainland that it constructed to save high generation cost & ensure the system stability and the supply of electric power of Cheju island (approximately 100km from south of mainland). The purpose of this study is to consider the complete maintenance of the HVDC Submarine Cable after its construction in 1997 while proposing future direction for the stable operation of the HVDC Submarine Cable.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.21 no.5
• /
• pp.583-590
• /
• 2015

Submarine cable installation is essentials for grid connection between existing power grid and newly produced electricity which will be from offshore wind farm in Southwest sea area of Korea. Especially, submarine cable route and protection method is designed in order to ensure the economical efficiency, workability and stability of submarine cable installation. On this paper, we will give the basic information about the submarine cable route and protection method of offshore wind farm which will be built in Southwest sea area of Korea. For this, we have a numerical simulation at high and low tide based on the third-generation wave model SWAN(Simulating WAves Nearshore) using the long term wave data from Korea Institute of Ocean Science and Technology(KIOST). The results of the study, year mean Hs is 1.03m, Tz is 4.47s and dominant wave direction is NW and SSW When the incident wave direction is NW(Hs: 7.0 m, Tp: 11.76s), the distribution of shallow water design wave height Hs was calculated about 4.0~5.0m at high tide and 2.0~3.0m at low tide. When the incident wave direction is SSW(Hs: 5.84 m, Tp: 11.15s), the distribution of shallow water design wave height Hs was calculated about 3.5~4.5m at high tide and 1.5~2.5m at low tide. The wave direction on a dominant influence in the section of longitude UTM 249749~251349(about 1.6 km) and UTM 251549~267749(about 16.2 km) in the submarine cable route are each NW and SSW. Prominently, wave focusing phenomenon appears between Wi-do and Hawangdeung-do, in this sea area is showing a relatively high wave hight than the surrounding sea areas.

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

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

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.31 no.6
• /
• pp.478-484
• /
• 2019

The submarine cable for Yongsu wave power plant was cut in 2014 winter. This study investigated the probability of high-wave occurrence exceeding the 50-year return period and the underestimation of armor unit weight used to protect the cable. The observation data from KMA buoy and the hindcast wave data were reviewed to determine the return period of wave height during the winter. In order to investigate the armor unit weight of cable-protection, we calculated the required weight of armor unit using not only Design Standard for Harbor and Fishery Port, but also the previous researches for the wave with large incident angle. As a result, it appeared that the high wave exceeding the 50-year return period did not occur during the winter of 2014 and the armor unit weight of the cable protection was not sufficient to sustain the obliquely incident wave, which induced the cable protection failure.