• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.728-732
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• 2004

기존의 지하 공동구 감시 시스템은 광케이블, 누설 동축케이블(LCX), 각종 제어케이블을 사용하여 통신 선로를 구축하기 때문에 시설비가 대단히 고가이며, 여러 가지 통신선로의 이용에 따른 유지보수가 어렵고 시공기간이 길어 시설 확대에 어려움이 있었다. 따라서 통신케이블의 설치 없이 기존에 설치된 공동구의 전등용 저압 전력선을 통신선로로 그대로 이용할 수 있는 전력선 통신 기술을 적용하여 유지보수가 용이한 저비용의 지하 공동구 감시제어시스템을 개발하는 것이 바람직하다. 본 논문에서는 공동구에서의 전력선 통신의 특성을 조사, 시험시스템 설계${\cdot}$제작, 현장실증시험을 통한 성능시험 및 분석을 수행하여 전력선 통신을 적용한 안정적인 공동구 감시제어 시스템을 제안하고자 한다.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.619-624
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• 1987

A study on distribution automation system suitable to distribution system of KEPCO has started since 1984, and the field trial system for ADS will be operated for testing. This paper will describe project and planning for field trial of KEPCO.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.74-75
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• 2011

EBOP(Electrical Balance of Plant)는 연료전지 출력인 DC 전원을 전력변환기술을 이용하여 계통 전원에 연계하는 계통 연계 인버터 시스템이다. 포스코파워에서 개발한 3MW급 EBOP 시스템은 국제 규격(IEEE std.1547, UL1741)에 의한 성능 검증 시험을 거치고 국내 2개 현장에 5기를 적용하여 운전 중이다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.4
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• pp.555-565
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• 2018

Nowadays, the artificial ground freezing (AGF) method has been used in many geotechnical engineering applications such as temporary excavation support, underpinning, and groundwater cutoff. The AGF method conducts the freezing process by employing a refrigerant circulating through a set of embedded freezing pipes to form frozen walls serving as an excavation support and cutoff wall. Two refrigerants of brine with the freezing temperature of $-20{\sim}-40^{\circ}C$ and liquid nitrogen with the freezing (evaporating) temperature of $-196^{\circ}C$ are commonly being used in geotechnical applications. This paper performed a series of field experiments to evaluate the freezing rate of marine clay in application of the AGF method. The field experiments consisted of the single freezing-pipe test and the frozen-wall formation test by circulating liquid nitrogen, which is a cryogenic refrigerant, into freezing pipes constructed at a depth of 3.2 m in the ground. The temperature of discharged liquid nitrogen was maintained through the automatic valve, and the temperature change induced by AGF method was measured at the freezing pipes and in the ground with time. According to the experimental results, the single freezing-pipe test consumed about 11.9 tons of liquid nitrogen for 3.5 days to form a cylindrical frozen body with the volume of about $2.12m^3$. In addition, the frozen-wall formation test used about 18 tons of liquid nitrogen for 4.1 days to form a frozen wall with the volume of about $7.04m^3$. The radial freezing rate decreased with increasing the radius of frozen body because the frozen area at a certain depth is proportional to the square of the radius. The radial freezing rate was formulated as a simple equation.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.5
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• pp.421-428
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• 2022

The earthwork is a core process of all constructions, and compaction measurement of earthwork play an important role in improving productivity. The analog tests such as Plate Bearing Test and Sand-cone occupy current compaction measurement techniques. Due to advanced 4th Industrial Revolution, research on analog tests combined smart construction technology are actively conducted. DCPT (Dynamic Cone penetration Test), simpler and faster than conventional tests, has recently on rise. However, it is also an analog that measures data manually and has several disadvantages such as history management and data verification. The IoT-based DCPT system developed in this study combines digital wire sensors, mobile phones, and Bluetooth with conventional DCPT. Compare to conventional test methods, IoT-based DCPT has advantages such as performance time, single-person measurement, low cost, mobile-based management, and real-time data verification. In addition, a test bed was built to verify IoT-based DCPT. The test bed was built under similar conditions to the actual earthworks site through roller equipment. DCPT data obtained from 322 stations. As a result, IoT-based DCPT showed good performance, and the test bed was also showed stable results as the compaction was carried out.

• The Magazine for Energy Service Companies
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• s.33
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• pp.54-57
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• 2005

일반적으로 건물이나 산업현장에 설치되는 항온항습기 및 공조 장치 등은 외기의 온도나 습도와 관계없이 관리자가 최초 설정한 값을 수동으로 변경시키지 않는 한 항온항습 또는 냉$\cdot$난방 기간중에 연중 또는 수개월 간 항상 일정한 실내 온$\cdot$습도를 유지하기 위해 많은 에너지를 소모하고 있다. 이러한 문제점에 착안하여 비교시험을 통한 실증시험을 수행한 이코노 공조기는 본문과 같은 여러 가지 기능들을 자동으로 수행하게 함으로써 공조부하 절감을 통하여 궁극적으로 에너지 절감을 이룰 수 있도록 제작된 기기이다.

• 전기의세계
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• v.42 no.8
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• pp.41-54
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• 1993

PSS는 향후 장기적인 전력공급 안정화를 위한 기술개발이나 기술력 향상에 전자계산기 이용기술과 더불어 상호 보완적으로 크게 이용되어야 한다. 더불어 전력회사 뿐만 아니라 관련 산업계, 학계까지를 망라한 우리나라의 전력기술 기반구축과 전문 기술인력의 양성을 위하여 PPS의 이용은 필수적인 것으로 생각된다. 기본적인 PSS의 기능 및 이용분야를 종합적으로 다시 한번 요약하면 아래와 같다. - 전력 계통 특수 기술현상 해석 - 현장 실증시험의 대체 및 신규 도입기술의 사용전 성능시험 - 고급전문 기술인력의 확보(교육훈련, 유치 및 양성) - 홍보 및 이해증진(전력계통 관련기술의 역할 및 중요성)

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.329-334
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• 2002

우리나라 전력계통의 특성상 남부의 전원단과 수도권의 부하중심단과의 거리가 존재하여 안정적인 계통전압제어에 어려움이 존재한다. 이러한 계통전압제어의 어려움을 극복하기 위해 154kV 계통에 SC Bank를 설치 운용중에 있다. 운전 환경상 차단기의 투입과 차단이 잦은 154kV SC Bank에 리액터가 소손되는 등의 문제점이 발생하고 있어 154kV SC Bank의 써지응답특성을 규명하고 차단기의 투입차단시 발생하는 써지전류의 저감에 대한 연구의 필요성이 대두되고 있다. 본 연구에서는 154kV SC Bank를 대상으로하여 현장조사와 현장실증을 통해 써지전류를 측정하고, 모의를 통해 써지응답특성을 규명하였다. 그 결과, 차단기의 접점의 상태와 피뢰기의 동작여부에 의해 써지전류가 크게 영향을 받는다는 점을 확인하였다. 154kV SV Bank를 대상으로 한 현장시험과 서지응답특성의 분석결과를 기본으로 하여 피뢰기의 영향과 차단기의 투입차단 영향을 최소화하는 방안으로 피뢰기의 분리운전으로 전류재단현상을 막아 급준써지전류의 발생을 억제하고 저항투압방식의 차단기로 써지전류를 30%이하로 억제할 수 있음을 실증과 모의로 확인하였다.

• Journal of the Korean GEO-environmental Society
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• v.12 no.10
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• pp.63-72
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• 2011

The high capacity bi-directional pile load test is an optimum pile load test method for high-rised buildings. Especially, a high pressure and double-acting bi-directional pile load testing, a special type of the high capacity bi-directional pile load test, is the most practical way to overcome limitations of loading capacities and constraints of field conditions, which was judged to be a very useful test method for requiring high loading capacities. Total of 2 high capacity bi-directional pile load tests(P-1 and P-2) were conducted in high-rised building sites in Korea. Based on the field load test results, the sufficiency ratio of loading capacities to design loads for P-1 and P-2 were 3.3 and 2.1, respectively. For P-2, the load test could not verify the design load if 1-directional loads applied slightly smaller than the actual applied load. Also, high capacity bi-directional pile load tests were difficult to determine an ultimate state of ground or piles, although the loads were applied until their maximum loads. Hence, finite element analyses were conducted to determine their ultimate states by calibrating and extrapolate with test results.

• Journal of the Korean Geotechnical Society
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• v.39 no.11
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• pp.85-95
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• 2023

This study implemented intelligent compaction technology at the construction site of the AY Highway in Gyeonggi Province, with a focus on obtaining the representative intelligent compaction value, CMV. The target CMV for quality control was established through trial construction, and the validation of the compaction quality control process based on intelligent compaction was conducted. The optimal approach for determining the target CMV was confirmed to be through linear regression of the average CMV measured within a 5-m radius from the plate load testing location. Upon assessing compaction quality against the target CMV, it was observed that the quality criteria outlined in the domestic intelligent compaction standard were met. However, the criteria outlined in Austria and the United States were not satisfied. Notably, indicators related to the variability of compaction quality did not meet the specified criteria, suggesting a stringent standard compared to the observed variability of CMV, ranging from 17% to 55%. Consequently, it is recommended to conduct additional field tests to further validate the compaction quality control process based on intelligent compaction. This will aid in confirming and enhancing the appropriateness of the regulations stipulated in each standard.