• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.547-549
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• 2000

This paper develops phase sensitive detector for diagnosis of distribution transformers. And to detect the $tan{\delta}$ more effectively, this paper used phase sensitive detector. The sensor in oil which could be placed inside of the distribution transformer can measures the $tan{\delta}$ in oil. This could be the important factor and information, and it could be used for the basic information for a precise diagnosis. Establishment of the proposed system helps to build the confidence in monitoring of the oil-filled transformers.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제25회 춘계학술대회
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• pp.224-231
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• 1997

Microscopic examination for the morphological estimation of wear debris on the oil-lubrcated moving system is an accepted method for machine condition and fault diagnosis. However wear particle anaysis has not been widely accepted industry because it is dependent on expert interpretation of particle morphology and relies on subjective assessment criteria. This paper was undertaken to estimate the morphology of wear debris on the oil-lubricated movig system by computer image analysis. The wear test was performed under different sliding conditions using a wear test device made in our laboratory and wear testing specimen of the pin-on-disk-type was rubbed in pararline series base oil. In order to describe characteristics of debris of various shape and size, four shape parameters (50% volumetric diameter, aspect, roundness and reflectivity) have been developed and outlined in the paper. A system using such techniques promises to obviate the need for subjective, human interpretation of particle morphology in machine condition monitoring.

• Journal of Advanced Marine Engineering and Technology
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• 제33권7호
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• pp.1044-1051
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• 2009

During contact between surfaces, there is wear and the generation of wear. The particles contained in the lubricating oil carry detailed and important monitoring information about the condition of the machine. Therefore, this paper was undertaken for the Ferrography system of wear debris generated from a lubricated moving machine surface. The lubricating wear test was performed under different experimental conditions using the Falex wear test of the Pin and V-Block types by Ti(C,N) coated. It was shown from the test results that wear particle concentration(WPC), wear severity index(Is) and size distribution have come out all higher with increases in sliding friction time. With the Ferrogram thin leaf wear debris as well as ball and plate type wear particles were observed.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제26회 추계학술대회
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• pp.59-65
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• 1997

The calibration of O.M.D is carried out experimentally and is analysed theoretically. O.M.D experimentally measures the change in optical density of artificially contaminated oil which contains Fe powder of 5, 10, 20, 30, 40, 50, 70, 100, 200 ppm. The change in optical density, D$_1$ means the logarithmic transmittance of I$_0$ over $I_1 D_2$ denotes the logarithmic transmittance I$_2$ over I$_1$ on electromagnetic force which arranges the ferrous particles along the line of magnetic force. The theoretical D$_1$ which increases linearly as increasing Fe concentrations, is analysed by light attenuation theory. The difference between theoretical D$_1$ and experimental D$_1$ is due to the attenuation of micro bubbles and the agglomeration of fine particles in the sample oil. The calibrated O.M.D is applied to the sample oil from the high-powered diesel engine. Also the results are compared with those out of the off-line techniques such as JOAP and ICP.

• Tribology and Lubricants
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• 제25권4호
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• pp.236-242
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• 2009

Oil viscosity is one of the important parameters for machinery condition monitoring. Basically, it is expressed as kinematic viscosity measured by capillary flow and dynamic or absolute viscosity measured by rotary shear viscometry. Recently, acoustic wave techniques appear in the market, measuring viscosity as the product of dynamic viscosity and density. For Newtonian fluids, knowledge of density allows conversion from one viscosity parameter to the other at a specific shear rate and temperature. In this work, oil samples with different chain lengths of viscosity index (VI) improvers and concentrations were examined by different viscometric techniques. Results showed that acoustic viscosity measurements give misleading results for oil samples with high molecular weight VI improvers and at low temperatures ${\leq}40^{\circ}C$.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2008년도 춘계학술발표회
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• pp.125-127
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• 2008

허베이스피리트호 원유유출 사고는 2007년 12월7일 아침 7시6분경 서해안 만리포 북서쪽 10km 해상에서 크레인을 적재한 1만1800t급 바지선이 정박 중인 흥콩 선적 유조선 허베이 스피리트호(14만6000t급)와 부딪치면서 발생했다. 이와 같은 기름 유출 사고의 경우, 유출 범위를 정확하게 이해하는 것이 중요하다. 여기서는 위 사고 기간에 얻어진 인공위성 자료를 이용하여 기름 유출을 탐지하기 위한 연구결과를 소개한다. 광학과 마이로파영상에 대해 유출 범위의 계산 및 해석 알고리듬에 대한 현재까지의 결과를 소개한다. 광학영상으로는 아리랑 2호 (다목적 실용위성 2호, KOMPSAT II) MSC(Multi Spectral Camera)자료가 사용되었으며, 합성개구레이더로는 ENVISAT ASAR, TerraSAR-X 및 ALOS PALSAR의 자료가 사용되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.11-19
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• 2004

When pile foundation constructed by driving method, it is desirable to perform monitoring and estimation of pile drivability and bearing capacity using some suitable tools. Dynamic Pile Monitoring yields information regarding the hammer, driving system, and pile and soil behaviour that can be used to confirm the assumptions of wave equation analysis. Dynamic Pile Monitoring is performed with the Pile Driving Analyser. The Pile Driving Analyser (PDA) uses wave propagation theory to compute numerous variables that fully describe the condition of the hammer-pile-soil system in real time, following each hammer impact. This approach allows immediate field verification of hammer performance, driving efficiency, and an estimate of pile capacity. The PDA has been used widely as a most effective control method of pile installations. A set of PDA test was performed at the site of Donghea-1 Gas Platform Jacket which is located east of Ulsan. The drilling core sediments of location of jacket subsoil are composed of mud and sand, silt. In this case study, the results of PDA test which was applied to measurement and estimation of large diameter open ended steel pipe pile driven by underwater hydraulic hammer, MHU-800S, at the marine sediments were summarized.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
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• pp.214-216
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• 2001

In this paper, we developed the on-line Diagnostic & Monitoring system of distribution transformers using wireless communication. The Diagnostic system consists of the top oil temperature sensing, ambient temperature sensing. load current sensing, acoustic emission peak-value sensing, acoustic emission pulse counter and wireless communication part. The Monitoring system consists of the communication setting, online monitoring and database construction part. The Diagnostic system send the date acquired from the some sensors of the distribution transformers to the host PC. The Monitoring program of the host PC store the data to database. And the Monitoring system estimates the loss of life from the DB. Thus it could be managed the career and the functional lifetime of the transformer more efficiently than existing methodologies.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.464-466
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• 2001

In this paper, we developed the on-line Data Aquisition System(DAS) of distribution transformers using the hardware and monitoring program. The DAS consists of the top oil temperature sensing part, ambient temperature sensing part, load current sensing part, acoustic emission peak-value sensing part, acoustic emission pulse counter part, micro-processor part and wireless communication part. The Monitoring System consists of the communication setting, online monitoring and database construction part. The DAS send the data acquired from the some sensors of the distribution transformers to the host PC. The monitoring program of the host PC stores the data to database. And the monitoring system estimates the loss of life time for distribution transformer from the DB. Thus, it could be managed the career and the functional lifetime of the transformer more efficiently than existing methodologies.

• Corrosion Science and Technology
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• 제15권6호
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• pp.271-280
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• 2016

An approach to achieving the ambitious goal of cost effectively extending the safe operation life of energy pipeline to 100 years is the application of health monitoring and life prediction tools that are able to provide both long-term remnant pipeline life prediction and in-situ pipeline condition monitoring. A critical step is the enhancement of technological capabilities that are required for understanding and quantifying the effects of key factors influencing buried steel pipeline corrosion and environmentally assisted materials degradation, and the development of condition monitoring technologies that are able to provide in-situ monitoring and site-specific warning of pipeline damage. This paper provides an overview of our current research aimed at developing new sensors and electrochemical cells for monitoring, categorising and quantifying the level and nature of external pipeline and coating damages under the combined effects of various inter-related variables and processes such as localised corrosion, coating cracking and disbondment, cathodic shielding, transit loss of cathodic protection.