• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.8
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• pp.131-137
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• 2005

The purpose of this paper is to evaluate the axial magnetic flux measurement could be used as a tool of the condition monitoring system for the induction motor and to develope the diagnostic algerian for the electric motors. The magnetic leakage flux signal is captured by the flux coil located at the end of motor without the disturbance of the operation. And the signal is analyzed both time and frequency bases to detect the failure of the motor. Specific signature can be described in time and frequency domain for each faults of the motor. The spectrum of the signal was found more useful for the monitoring purpose. The supply voltage imbalance and tin to turn failure of the stator winding could be detected by analysing the specific sidebands of the axial flux and sideband of the rotor bar pass frequency with the high resolution spectrum. The goal of this study verity that the axial flux measurement for the induction motor is a powerful tool for the diagnostic method and develope the algorithm to detect the fault.

• Proceedings of the KIEE Conference
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• 2000.11a
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• pp.177-179
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• 2000

In this paper, we developed the online Monitoring & Diagnostic(MD) system of distribution transformers. It consists of the Data Acquisition(DA) module and the DataBase(DB) module. The acquired data from the distribution transformers is stored to the DB in an on-line. The DB is planned and made to the RDBMS (Relative DataBase Management System) to manage the data efficiently. The developed MD 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 systems. In the case study, the oil temperature rising experiment is performed by using the back loading method in the laboratory level. From the results, the proposed MB system can be a practical applications for the distribution transformers.

• Nuclear Engineering and Technology
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• v.49 no.3
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• pp.484-494
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• 2017

In industrial plants such as nuclear power plants, system operations are performed by embedded controllers orchestrated by Supervisory Control and Data Acquisition (SCADA) software. A targeted attack (also termed a control aware attack) on the controller/SCADA software can lead a control system to operate in an unsafe mode or sometimes to complete shutdown of the plant. Such malware attacks can result in tremendous cost to the organization for recovery, cleanup, and maintenance activity. SCADA systems in operational mode generate huge log files. These files are useful in analysis of the plant behavior and diagnostics during an ongoing attack. However, they are bulky and difficult for manual inspection. Data mining techniques such as least squares approximation and computational methods can be used in the analysis of logs and to take proactive actions when required. This paper explores methodologies and algorithms so as to develop an effective monitoring scheme against control aware cyber attacks. It also explains soft computation techniques such as the computational geometric method and least squares approximation that can be effective in monitor design. This paper provides insights into diagnostic monitoring of its effectiveness by attack simulations on a four-tank model and using computation techniques to diagnose it. Cyber security of instrumentation and control systems used in nuclear power plants is of paramount importance and hence could be a possible target of such applications.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.183-185
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• 2002

본 논문에서는 안정적인 변전소의 운영을 위해 최근 개발된 WEB 기반의 초고압 변전설비 원격감시 및 진단 시스템을 소개한다 WEB 기반의 초고압 변전설비 원격 감시 및 진단 시스템은 154kV급 이상의 초고압 변전소에 설치되어 있는 주변압기(MTR)와 가스절연개폐기(GIS)에 대한 감시 및 진단 데이터를 취득하는 Local System과 이러한 데이터를 전송 받아 감시 및 진단 기능과 WEB 서비스를 수행하는 Main Control Center로 구분된다. 실적용 사례로 최근 산업체의 몇 개 공장을 대상으로 시범 적응한 154kV급 변전소의 WEB 기반 감시 및 진단 시스템을 소개한다. 나아가 변전기기를 제어하기 위한 시스템과의 연계 방법에 대해 언급하고 있다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2114-2115
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• 2008

We consider the relation between on-line monitoring and diagnostics on the one hand and high-voltage (HV) withstand and partial discharge (PD) on-site testing on the other. HV testing supplies the basic data (fingerprints) for diagnostics. In case of warnings by on-line diagnostic systems, off-line withstand and PD testing delivers the best possible information about defects and enables the classification of the risk. Frequency tuned resonant (ACRF) test systems are best adapted to on-site conditions. They can be simply combined with PD measuring equipment. The available ACRF test systems and their application to electric power equipment -from cable systems to power transformers is described.

• KSBB Journal
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• v.15 no.5
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• pp.423-427
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• 2000

Intense research on biosensors has been performed in a number of different institution over the past 15 years, but relatively few commercial products have resultingly, the blood glucose sensor is a good example of a product which penetrated the market. However recently, the development of electrochemical and optical technologies has accelerated the turnover of the research as is illustrated by a rapid increase in the number of point-of-care diagnostic systems and analytical devices. Examples of such biosensors used in the fields of medical diagnostics, bioprocess control, and environmental monitoring are described, and summarized in an introduction to their characteristics, structures, and functions, given.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.230-234
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• 2008

Urban Railway was used importantly with transport for several decades. This transportation facilities used electricity. When the breakdown occurs, social, the economic loss is enormous. In addition to, the power equipment was ageing. We need preventive diagnostic monitoring system in order to prevent breakdown of power equipment. In this paper, we investigates characteristic and breakdown type of the Urban Railway power equipment. Through the this research, we can contribute in the operation which power equipment is efficient of the Urban Railway.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.550-551
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• 2000

This paper suggests the system which monitors and diagnoses the distribution transformers. Moreover, this paper has established the system for the multi diagnoses by all the informations. Through the proven oil sensor, the oil temperature, capacitance and $tan{\delta}$ could be measured throughly, and followed by these informations, detected problems of the distribution transformers, using wireless data communication, could directly reported to the main host. For this, the proposed system is divided into sensor part and controller part. To prove the usefulness of the system, the paper compared and analyzed the system with the existing one, and after studying the correlation of the both, the result proved its goodness.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.10a
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• pp.325-329
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• 1992

The development of automatic production system have required intelligent diagnostic and monitoring function to repair system failure and reduce production loss by the failure. In order to perform accurate functions of intelligent system, inference about total system failure and fault analysis due to each mechanical component failures are required. Also the solution about repair and maintenance can be suggested from these analysis results. Generally, bearing is a essential mechanical component in the machinery. The bearing failure is caused by lubricant system failure, metallurgical defficiency, mechanical condition(vibration overloading misalignment), environmental effect. This study described roller bearing fault train due to stress variation and metallurgical defficiency from lubricant failure by using FTA.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.19-21
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• 2001

Induction motors are a critical component of many industrial machines and are frequently integrated in commercial equipment. The many economical losses and the deterioration of system reliability might be caused by the failure of induction motors in industrial field. Based on the reliability and cost competitiveness of driving system(motors), the faults detection and diagnosis of system is considered very important factors. In order to perform the faults detection and diagnosis of motors, the vibration monitoring method and motor current signature analysis (MCSA) method are emphasized. In this paper, MCSA method is used for induction motor fault diagnosis. This method analyzes the motor's supply current, since this diagnoses the motor's condition. The diagnostic system is constructed by using LabVIEW of National Instruments.