• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.377_378
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• 2009

HVDC 케이블은 장거리 전력전송, 국가간 계통연계, 비동기 전력계통연계, 전력의 시장화에 따른 전력공급 제어 필요에 따라 세계적으로 널리 사용되고 있다. 국내에서는 현재 유일하게 제주-해남간 180kV HVDC 해저케이블이 운영 중에 있으며, 향후 제주도의 안정적인 전력공급을 위하여 2011년에 제주-육지간 250kV HVDC 해저케이블이 추가로 건설될 예정이다. 그래서 HVDC 해저케이블의 신속 정확하게 안정적이고 신뢰성 있는 운영을 위해서 국내에서 자체 개발한 HVDC 해저케이블에 대한 장기과통전 시험에 대한 평가 및 절차가 필요하게 되었다. 본 논문에서는 HVDC 해저케이블의 장기과통전 시험평가를 위하여 전기적 시험은 CIGRE에서 권고하고 있는 Electra 189, 219에 근거하고 기계적 시험은 IEC 60055-1, Elecrta 171에 근거하여 기술하고자 한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.11
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• pp.89-95
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• 2013

In resent years, Offshore Wind Farm (OWF) is being actively developed. Typically, OWF has a better wind resource than onshore one, but also have a very high investment cost and maintenance cost. Furthermore, due to a difficulty of geographical access, OWF can be affected by the failure for a longer time. As the result, OWF has a higher loss cost. Therefore, a reliability evaluation should be performed more carefully at OWF planning stage. In this paper, a methodology for the reliability evaluation on inner grid is suggested. Inner grid connects wind turbines via submarine cables and transfers power to offshore substation. According to location of the faulted cable under layouts of inner grid, the transfer ability of inner grid is influenced. In order to indicate the transfer ability of inner grid, several indices are introduced such as PNDR, EEND and EENDC. To demonstrate the methodology described in this paper, diversity case studies were performed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.92-92
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• 2010

In this paper, the test is performed on MgO, which is used as a filler in epoxy additives, respectively (0, 1.0, 3.0, 5.0, 7.0, 10 [wt%]) for HVDC(high voltage direct current) submarine cable insulating material to improve electrical properties of epoxy resin in high temperature. The breakdown strength due to increasing amount of filler increased to 5.0 [wt%] by the effects of the Coulomb blockade. However, it is confirmed that strength of dielectric breakdown decreased because the filler functioned as impurities and affected the breakdown when filler additive exceeded by 5.0 [wt%] or more. We have found that the highest dielectric breakdown strength of specimen added 5.0 wt% at $25^{\circ}C$, and is more increased approximately 13.7 [%] than virgin specimen.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.48-48
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• 2010

In this paper, we have investigated temperature dependence of dielectric breakdown voltage at epoxy with added nano-filler(MgO), which is used as a filler of epoxy additives for HVDC(high voltage direct current) submarine cable insulating material with high thermal conductivity and restraining tree to improve electrical properties of epoxy resin in high temperature region. In order to find dispersion of the specimen, the cross sectional area of nano-composite material is observed by using the SEM(Scanning Electron Microscope) and it is conformed that each specimen is evenly distributed without the cohesion. As a result, it is confirmed that the strength of breakdown of all specimen at 50 [$^{\circ}C$] decreased more than that of the dielectric breakdown strength at room temperature. When temperature increases from 50 [$^{\circ}C$] to 100 [$^{\circ}C$], we have confirmed that breakdown strength of virgin specimen decreases, but specimens with added MgO show constant dielectric breakdown strength.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.1
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• pp.167-180
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• 2013

A capstone design is regarded as one of cap courses in undergraduate engineering education because it requires most prerequisites and makes students experience real engineering design processes. There have been case studies to show how this subject should be organized, practiced, and optimized. This study shows one of the case studies by focusing offshore wind power, one of newly recognized renewable energy resources, especially targeting for the design of wind turbine foundation and submarine power cable protectors mainly because of current energy and global warming crisis. To pinpoint engineering design, the students'activities during the project and design procedures are monitored, evaluated, and recommended; hence, core factors are addressed to develop successful aim, theory, practice, and other necessities. These factors include creative problem solving abilities; recognition of engineering curriculum; selection of project theme based on significance, ripple effect, and education purpose; team organization by the full brain model; systematization of project process; realization of engineering design; and synthesis of evaluation. In the end, the aftermath and future works are discussed.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.574-578
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• 2011

본 논문에서는 해저케이블 부두 하역용 장비인 코일링 암(coiling arm)에 대한 구조설계 및 해석을 수행하였다. 본 연구에서는 구조설계를 위해 3차원 CAD프로그램을 이용하여 모델링하였고 구조해석 프로그램을 이용하여 유한요소법에 기초한 전산해석 기법으로 해석을 수행하였다. 코일링 암의 목적에 맞추어 케이블을 케이블 탱크에 가이드 할 수 있도록 베어링 및 롤러를 설계하여 메인 암이 회전하고 케이블 가이드가 이동할 수 있도록 하였고, 기존의 외국 모델에서 사용하던 와이어 및 모터 시스템을 이용한 케이블 가이드 작동방식을 유압 시스템을 이용한 작동방식으로 변경하여 설계 및 제작이 쉽고 사용자가 직관적으로 작동할 수 있도록 설계하였다. 자중 및 케이블 하중에 대한 응력 해석을 수행하였고, 유압시스템에 의한 파손 가능성을 고려하였다. 케이블 가이드에 이동 및 지면 경사도에 따른 전복해석을 수행하였으며, 설치 장소를 고려한 풍하중 효과도 추가로 고려하였다. 본 연구를 통해 코일링 암의 작동방식을 개선하였으며 설계 및 해석 방법을 확립과 더불어 국내 최초로 실제 코일링 암을 제작 및 설치하였다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.369-377
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• 2014

In this paper, to recognize the collision behavior between a submerged floating tunnel(SFT) and underwater navigation vessel(UNV), both structures are modeled and analyzed. The SFT of collision point is modeled tubular section using concrete with steel lining. The other part of SFT is modeled elastic beam elements. Mooring lines are modeled as cable elements with tension. The under water navigation vessel is assumed 1800DT submarine and its total mass at collision is obtained with hydrodynamic added mass. The buoyancy force on SFT is included in initial condition using dynamic relaxation method. The buoyancy ratio (B/W) and the collision speed are considered as the collision conditions. As results, energy dissipation is concentrated on the SFT and that of the UNV is minor. Additionally, the collision behaviors are greatly affected by B/W and the tension of mooring lines. Especially, the collision forces are shown different tendency compare to vessel collision force of current design code.

• Journal of the Korean Solar Energy Society
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• v.34 no.1
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• pp.81-90
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• 2014

The Jeju-Korea power system is a small-sized network with a system demand ranging from a autumn minimum of 350MW to a summer peak of 716MW. Because Jeju island is well exposed to north-east winds with high speed, applications to connect to Jeju power system are flooded. Considering physical/environmental constraints, Jeju Self-governing Province has also target for the wind power capacity of 1,350MW by 2020. It amounts to two or three times of Jeju average-demand power and wind power limit capacity announced by Korea Power Exchange (KPX) company. Wind farm connection agreements will be signed to maximize utilization of wind resource. In spite of submarine cable HVDC connected to Korea mainland, Jeju power system is independently operated by frequency and reserve control. This study reevaluates wind power limit based on the KPX criteria from 2016 to 2020. First of all wind power generation limit are affected by off-peak demand in Jeju power system. Also the possibility capacity rate of charging wind power output is evaluated by using energy storage system (ESS). As a result, in case of using 110MWh ESS, wind power limit increases 33~55MW(30~50% of ESS), wind power constraint energy decreases from 68,539MWh to 50,301MWh and wind farm capacity factor increases from 25.9 to 26.1% in 2020.

• Journal of the Korean Institute of Gas
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• v.4 no.3 s.11
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• pp.26-32
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• 2000

Because of the continuous growth of energy consumption, and also the tendency to site power lines and pipelines along the same routes, the close proximity of high voltage structures and metallic pipelines has become more and more frequent. Moreover, normal steady state and fault currents become higher as electric networks increase in size and power Therefore, there has been and still is a growing concern(safety of people marking contact with pipeline, risk of damage to the pipeline coating, the metal and equipment connected to pipeline, especially cathodic protection system) about possible hazards resulting from the influence of high voltage power system on metallic structures(gas pipeline, oil pipeline and water pipeline etc.). Therefore, we analyze the interference problems when the gas pipeline is buried with power cable in the same submarine tunnel. This paper present the results of the study about interference mechanism, AC corrosion limitation of safety voltage and analysis of induction voltage.

• Journal of Korea Port Economic Association
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• v.31 no.2
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• pp.41-53
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• 2015

In Paracomon Inc. v. Telus Communication, Realice's anchor became entangled with a working fiber-optic submarine cable during its voyage and are presentative of the shipowner(the captain) cut the cable. The owner of the cable brought a claim for the repair cost against the shipowner. The shipowner then advanced a third party claim against a liability insurance underwriter. The Supreme Court of Canada (SCC) held that the shipowner was entitled to limit its liability under the 1976 Convention on the Limitation of Liability for Maritime Claims. The SCC also ruled that even though the misdeed of the shipowner was insufficient to break its right to limitation of liability, its wrongdoing constituted willful misconduct under the 1993 Canada Marine Insurance Act, allowing the underwriter to deny coverage for the incident. Thecasewasthefirsttoaddresstheinterrelationship between the shipowner's right to limit liability under the international convention regime and the availability of liability insurance with respect to such limited liability. This study analyzes the reasoning behind the SCC's judgment and evaluates the appropriateness of this court's decision based on the current maritime industry as well as prevailing maritime law. It concludes that the SCC's decision to declare that the shipowner retained the right to limit its liability is appropriate under the Limitation Convention (1976). However, its declaration that the liability insurer was discharged from liability is not correct in due consideration of the common recognition in the maritime industry, the intended purpose of a third party's right against the liability insurer, and the adoption process of the conduct barring limitation. Based on the SCC's decision, this study finally reviews the issue of the shipowner's right to limit and the coverage of the liability insurer in the Sewol case (2014).