• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.711-713
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• 2004

In the past time, the protection relay did only a protection function. Currently, its upgraded device i.e. IED(Intelligent Electric Device) has been designed to protect, control, and monitor the whole power system automatically. Also the device is desired to successfully measure important elements of the power system. This paper considers design method of a digital protection IED with a function of measuring various elements and a communication function. The protection IED is composed of the specific function modules that are signal process module, communication module, input/output module and main control module. A signal process module use a DSP processor for analysis of input signal. Main control module use a embedded processor, Xscale, that has an ARM Core. The communication protocol uses IEC61850 protocol that becomes standard in the future. The protection IED is able to process mass information with high-performance processor. As each function module is designed individually, the reliability of the device can be enhanced.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.760-761
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• 2011

Ground differential relay is used to provide fast, sensitive, and selective protection for the wye connected and grounded electrical power equipment such as generators, power transformers, and grounding transformers. The ground differential protection only protects the ground faults within the protection zone, so that it can't protect the line-to-line fault. This paper proposes the algorithm to provide the protection for the line-to-line fault through the ground differential protection. The proposed algorithm detects the line-to-line fault of transformer using the comparison between the positive and the negative current, when the ground differential relay dose not operate. The performance of the algorithm is verified using a PSCAD/EMTDC simulator under various case studies.

• 전기학회논문지P
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• 제63권3호
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• pp.149-156
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• 2014

Generator of hydroelectric generating unit is to be protected by the digital protection IED. Now, any IED of large capacity for hydro power plant was not developed by domestic technology. This is because it is required for the generator of the high reliability technology and considered as due to the sale of the market of IED device is small. However, the protection IED must be develop by domestic technology to meet the advanced needs of the construction and replacement of electrical equipment in accordance with the new power plant development. In this paper, a digital algorithms for protection IED of large size of hydroelectric generating unit were designed. The algorithms consist of the stator protection, anti-motoring, overexcitation and loss of excitation. The performance of the algorithms were evaluated by using the simulation data collected from the PSCAD/EMTDC software. From test results, it can be seen that the developed algorithms were not maloperation.

• 한국통신학회논문지
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• 제29권4C호
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• pp.454-460
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• 2004

본 논문에서는 Ka대역 초고속 위성방송 시스템에서 강우감쇠에 대처하면서 가입자에게 지속적으로 방송을 제공하기 위해 Unequal Error Protection(UEP) 방식을 이용한 계층적 부호화 방식에 대한 연구를 하였다. 신호의 중요도에 따라 변조 방식 및 채널 코딩 방식을 달리하는 time sharing 방식과 달리 하나의 변조방식을 이용하여 성상도 위치에서 신호의 중요도에 따라 신호간의 최소거리를 다르게 배치하는 UEP방식에 대한 구조 및 성능을 분석하였으며. 성능분석을 토대로 최적의 방식을 제시하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.202-209
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• 2000

This paper introduces the main function and protection method of IGBT gate driver that designed by KOROS. Recently, the applications of insulated gate bipolar transistors(IGBTs) have expanded widely, particularly in the area of railway converters. This driver is suitable for railway traction applications, so they are designed for circumstance of railway vehicle such as vibration. The input control power for this driver is supplied from battery charger of railway. it is no necessary an isolated power supply board or auxiliary power supply, with substantial savings in cost and space in railway applications. This gate driver can be used wide range of input voltage. So, performance of the driver has no relation with the battery voltage(70V∼110V). The protection methods of IGBT gate driver have many kind of ways, but this gate driver it designed to apply to converter for railway system, so this gate driver includes protection for arm short current and low control power voltage, etc. And the process of protection method and protection reference value are optimized by means of sufficient test with our own facilities.

• 디지털융복합연구
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• 제13권10호
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• pp.377-383
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• 2015

본 연구는 방사선을 이용한 검사 시 방사선 방어용 앞치마(apron)의 성능이 좋지 못할 경우 방사선 작업종사자의 피폭이 상대적으로 높아질 수밖에 없음에 따라 영상평가 프로그램인 Image J의 최대 신호 대 잡음비 값을 측정하여 융복합 방어 성능평가와, 우수한 성능의 apron을 구비 할 수 있는 기초자료를 도출하고, 선량계 없이도 성능 평가 방법의 접근을 용이하게 하여 주기적이고 철저한 apron관리의 용이성을 확보하고자 하였다. 각각 32벌의 apron 9군데의 최대 신호 대 잡음비 값을 비교한 결과 상태가 양호한 apron의 경우 27 dB이상으로 나타났고 상태가 불량한 apron의 경우 24 dB미만으로 측정되어 각각의 성능이 뚜렷하게 구별 되는 것이 확인되었다. 통계분석결과 정규성 분포를 보여 t-test를 실시한 결과 p<0.001로 두 결과 값은 통계적으로 유의하였다. 이에 따라 방사선 작업종사자의 방사선피폭을 최대한 줄이기 위해 선량계 없이 최대 신호 대 잡음비 값 측정만으로 apron의 성능 평가가 용이하여 방사선 작업종사자 및 환자의 불필요한 피폭 관리가 용이하게 되었다.

• 한국의류산업학회지
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• 제15권3호
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• pp.452-460
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• 2013

This study conducted a performance evaluation of protective clothing materials used for welding in a hazardous shipbuilding industry work environment. The welding process was selected as the one that most requires industrial protective clothing according to work environment characteristics. Flame proofing and convection heat protection performance (HTI) in the heat transfer characteristics of protective clothing material were indicated in the order of SW1(Oxidant carbon)>SW2(silica coated Oxidant carbon)>SW4(Oxidant carbon/p-aramid)>SW3(flame proofing cotton). However, radiant heat protection performance (RHTI) and the heat transfer factor (TF) were indicated in the order of SW1>SW4>SW2>SW3 and showed different patterns from the convection heat protection performance. SW1 showed superior air permeability and water vapor permeability. The tensile strength and tear strength of welding protective clothing material were indicated in the order of SW4>SW2>SW3>SW1 and showed that a blend fabric of p-aramid was the most superior for the mechanical properties of SW4. SW1 had excellent heat transfer properties in yet met the minimum performance requirements of tensile strength proved to be inappropriate as being a material for welding protective clothing. The abrasion resistance of woven fabric proved superior compared to nonwoven fabric; however, seam strength and dimensional change both met the minimum performance requirements and indicated that all samples appeared non-hazardous. Finally, oxidant carbon/p-aramid blend fabric appeared appropriate as a protective clothing materials for welding.

• Ocean and Polar Research
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• 제45권1호
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• pp.11-22
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• 2023

For the commercial development of deep-sea mineral resources, the International Seabed Authority is engaged in wide ranging discussions to establish the Regulations on Exploitation. The core issue of the Regulations on Exploitation is how to protect the marine environment along with the royalty system that distributes the profits from such development. The United Nations Convention on the Law of the Sea stipulates the protection of the marine environment in Part 12 (Articles 192-237) for the preservation of the marine environment, and in the 1994 Implementation Agreement, the protection of the marine environment at the stage of application for approval of the plan of work together with the Regulations on Exploration for the protection of the marine environment. For this purpose, certain obligations are imposed on the applicants. In the Regulations on Exploitation, financial systems such as environmental performance guarantee, insurance, and environmental compensation funds, which were not found in the Regulations on Exploration, are added to further specify the measures for marine environment protection generally stipulated in the 1982 Law of the Convention or 1994 Implementation Agreement. Regarding the financial system for marine environment protection, the Marine Environmental Protection and Conservation Informal Working Group meeting is revising the purpose of the environmental compensation fund. Among these financial system elements, it is judged that there is a possibility that the environmental performance guarantee and insurance may overlap considerably, and it is also thought that the establishment of the environmental compensation fund can also provide a substantial sum of money that will meet the purpose of the compensation fund in terms of securing its financial resources. In this paper, the question is posed as to whether or not this can be accomplished. In this respect, this paper examines the environmental performance guarantee, insurance, and environmental compensation fund, which are necessary for the protection of the marine environment of the deep seabed, but which can impose appropriate obligations on contractors for the commercial development of deep seabed mineral resources. At the same time as figuring out how it is operated in relation to relevant domestic laws, I would like to propose a plan to reflect the implications derived from the domestic law operation process in the Regulations on Exploitation.

• 한국지반환경공학회 논문집
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• 제15권11호
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• pp.53-59
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• 2014

낙석방지망에 대한 기존 연구 결과에 의하면 종래의 낙석방지망에서 발생되는 대표적인 문제점으로 이완성이 없는 횡방향 와이어로프에 의해 발생되는 낙석 중량의 누적현상, 지반과 낙석방지망의 결합지점 부족으로 인한 인발지지력 부족, 낙석의 과도한 충격으로 인한 철망의 빈번한 파손, 낙석방지망의 유지관리 시 철망의 재사용의 어려움 등이 보고되고 있다. 선행 연구를 통해 실내에서의 인장력과 현장실험이 실시되어 새로운 낙석방지망의 효과를 검증한 바 있다. 선행연구에 이어 본 연구에서는 기존의 사각낙석방지망과 비교하여 충격 완화형 육각 낙석방지망의 전체적인 구조적 안정성과 성능을 수치해석적 방법을 통해 점검하는 것에 그 목적이 있으며, 이를 충분히 검토하고 결과를 얻을 수 있도록 수치해석 프로그램이 설정되었다. 수치해석 결과를 종합해볼 때 동일한 단일 셀 간격 뿐만 아니라 동일한 면적비로 비교하더라도 육각 낙석방지망이 사각 낙석방지망에 비해 하중분배 효과가 우수한 것으로 나타났으며, 육각 낙석방지망은 낙석하중이 작용할 경우 이를 효율적으로 분산시킴으로써 과도한 하중 집중이 발생하는 것을 피할 수 있어 장기적인 안정성 확보에 유리할 것으로 판단된다.

• Corrosion Science and Technology
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• 제21권1호
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• pp.1-8
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• 2022

The use of cathodic protection for metals can be achieved by sacrificial anode CP or impressed current CP, or a combination of both. Cathodic protection is a highly effective anti-corrosion technique for submerged metals or metals in soil. But because the non-immersion atmospheric automobile environment is a high resistance environment, it is limited by fundamental cathodic protection. However, the application of cathodic protection to automobiles is attractive because of the possibility of maintaining corrosion resistance while using lower-cost materials. A commercially available product for automobiles that uses both sacrificial anode CP and impressed current CP was tested in a periodic salt spray environment to investigate the performance of the devices. Experimental results show that the metal to be protected has different anti-corrosion effects depending on the distance from the anode of the device, but it is effective for the entire 120 cm long specimen exposed with one anode. The cathodic protection is effective because the conductive tape attached to the anode of the structure to be protected acts as a constant electrolyte in wet and dry conditions. The results show that the entire standard passenger car can be protected by cathodic protection with 4 anodes.