• KIEE International Transactions on Electrophysics and Applications
• /
• v.3C no.6
• /
• pp.224-229
• /
• 2003

An ultra high frequency (UHF) coupler possessing ultra wide band (UWB) characteristics ranging from hundreds of MHz to several GHz is desirable for the detection of the partial discharge (PD) pulses because the pulses propagate with rise time shorter than one nanosecond in a gas-insulated substation (GIS). Thus, the authors have proposed a log-periodic antenna for GIS PD detection. Various parameters of the coupler such as frequency bandwidth, coupler gain, radiation pattern, and coupler geometry were considered throughout the simulations. The experiments for the detection characteristics of the coupler were carried out in the mock-up GIS chamber. The results indicated that the detection characteristics of the coupler are dependent on the installation angle of the coupler, the position of the coupler in the hand hole and the existence of the spacer.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.3C no.6
• /
• pp.236-240
• /
• 2003

The UWB UHF coupler for GIS PD detection requires a balun (balance to unbalance transformer) to show its inherent UWB characteristics. In order to reduce the size of the balun and to make it practical in the conventional GIS, a novel tapered coaxial balun with a dielectric was proposed for the UWB UHF coupler. The performance of the proposed balun was verified through a series of simulations, measurements and experiments. As a result, both the conventional balun and the proposed balun, which has a length equal to one third of that of the conventional balun, demonstrated good S11 characteristics, whereas the efficiency of the proposed balun increased as much as about 30% in comparison to the conventional one.

• Proceedings of the KIEE Conference
• /
• 2004.05b
• /
• pp.136-139
• /
• 2004

It is widely known that the ultra high frequency (UHF) method that detects the electromagnetic wave of the PD pulses in the gas insulated space is one of the most competitive methods for its high sensitivity. From the above point of view, this paper describes the propagation characteristics of GIS PD signals measured with ultra wide band (UWB) GIS PD detecting system in which PD signals are detected into the dual UHF band. The UWB PD detection system consists of the UWB UHF coupler, the UWB low noise amplifier (LNA) and the oscilloscope. The dual bands for PD signals are 0.5-2GHz(full band) and 1-2GHz(high band). As results, propagation characteristics of GIS PD signals were measured in the mock-up GIS bus and it was found that the propagation characteristics of the high band showed a better result in accordance with the infernal configuration of the GIS bus than those of the full band.

• Proceedings of the SAREK Conference
• /
• 2008.11a
• /
• pp.642-648
• /
• 2008

In order to analyze the causes of fossil power plant facilities due to a degradation and corrosion, artificial degraded materials composed of the facilities were manufactured. Various experiment were performed based on mechanical test, microstructure observation, hardness test, electrochemical potentiokinetic reactivation test(EPR) and corrosion scale thickness measurement test. The master curves were write out using Larson-Miller parameter to evaluate the degree of degradation with the above diagnosis methods. These data were applied to materials database of fossil power plant diagnosis. Finally expert system on the fossil power plant diagnosis was developed using the master curves and diagnosis algorithms.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.28 no.3
• /
• pp.78-83
• /
• 2014

To minimize the financial loss due to power facility malfunction, on-line diagnostic techniques are required to grasp any abnormal state of facilities in the live line as well as devices to diagnose abnormal states of power facility in an easy and prompt manner. This study aims to develop a portable UV detecting system by means of UV sensors for easier and efficient inspection of the degradation state of power facility in a long distance. Accordingly, it includes a simulation of corona discharges that may occur due to degradation of power facility and detection of ultraviolet pulse generation depending on the corona discharge intensity and measuring distance in application of UV sensors. Additionally, the optimal algorithm is determined for its application to the system's degradation diagnosis program based on the measured experiment data.

• Journal of the Korea Institute of Building Construction
• /
• v.20 no.6
• /
• pp.555-566
• /
• 2020

Recently, the aging of public facilities in Korea have accelerated, and the existing framework for facility management is shifting toward to facility asset management in terms of performance-based proactive control. Therefore, the operation of public facility involves both safety assurance from the deteriorated facilities and management capabilities for sustainable maintenance in the required valuation and level of service, such as valuation of facility assets, life-cycle management plans, financing, and so on. In this study, the Facility Asset Management Indicator(FAMI) has been developed for public facility asset management, and it provides the quantitative management grade, based on international standards, such as ISO 55000 series and International Infrastructure Management Manual(IIMM). The FMMI includes 10 key areas to apply a diagnosis model into management capabilities, 113 detailed elements, and 5 maturity grades. As the importance of public facility asset management is increasing constantly, this is expected to identify previously the strengths and weaknesses of public facility operating institutions. Eventually, they can obtain the effective ways to improve their own capabilities, minimize the public funds, establish the strategies for innovating the current management structures, and operate stably the facilities in the required performance.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10a
• /
• pp.286-291
• /
• 1990

We studied about the adopted system to POSCO facility which is very complexity and various as an example for studying a facility diagnosis and management system that is starting to be distinguished in the nowadays. At the first, explain what's the background why POSCO adopted the system, and it's goal, and it's promoting direction and ways. And there after studied it's results and effective analysis. Finally inquiry about the future improvement and development items through problems which become known during the project periods.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.56 no.1
• /
• pp.56-62
• /
• 2007

In this paper, design method for power tower hazard diagnosis/predition system based on UsN was proposed. The proposed method used multi-hybrid sensors to measure rotation, displacement, and inclination state of power tower, and made decision/prediction of hazard of power tower. System design was made with requirement analysis of monitoring for transmission power facility and use of MEMS and optic fiber sensors. For hazard decision, analysis of correlation was made using sensor output. LN based on IEC61850,international standard for digital substation, was also proposed. For transmission facility monitoring, digital substation and power tower were considered as parts of power facility networks.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.6
• /
• pp.870-875
• /
• 2013

After introducing diagnosis equipment power failure prevention activities for distribution system have become more active. To do facility diagnosis and maintenance work more efficiently we need to evaluate reliability for the system and should determine the priority line with appropriate criteria. Thus, to calculate risk factor for the power distribution line that are composed of many component facilities its historical failure events for the last 5 years are collected and analysed. The failure statics show that more than 60% of various failures are related to environment factors randomly and about 20% of the failures are refer to the aging. As a strategic evaluation system reflecting these environmental influence is needed, a system on the basis of the probabilistic approach related statical variables in terms of failure rate and failure probability of electrical components is proposed. The figures for the evaluation are derived from the field failure DB. With adopting Bayesian rule we can calculate easily about conditional probability query. The proposed evaluation system is demonstrated with model system and the calculated indices representing the properties of the model line are discussed.

• Journal of the Korea Society of Computer and Information
• /
• v.16 no.2
• /
• pp.141-151
• /
• 2011

This paper suggests the Facility Management System for plant factory promising to be a core technology of the agriculture in the future. This system makes diagnoses that status from sensors or facilities in the factory for exact operation and monitors the internal environment with the control status in real-time. It is expected that we could operate a plant factory safely and effectively by using the system. The system consists of the data management module, the context provider module, the context interpreter module, the service provider module, the data storage and user interface. The system provide with the failure diagnosis service, the facility control service, and the high-reliability monitoring service via the interactions between above modules. The failure diagnosis service determines whether the sensors or facility devices are in failure or not, and informs the administrator of their conditions. The facility control service is activated in case if the facilities need to be managed during the diagnosis for failure or malfunction processes. The high-reliability monitoring service provides the administrator with verified data through the failure diagnosis service. Then we confirmed that the suggested system operates correctly through the system simulation.