• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.667-669
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• 2005

지중배전선로에 설치되어 있는 23kV 수동개폐기의 고장표시 상태를 단말장치와 소출력 RF 통신을 이용하여 배전자동화 주장치에서 FII(Fault Indicator)로 고장 판단할 수 있는 시스템 구성에 대해 논하고자 한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.94-105
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• 2010

To detect faults in an inverter-fed permanent magnet synchronous motor (PMSM) drive under the circumstance having faults in a stator winding and inverter switch, an on-line basis fault detecting scheme during operation is presented. The proposed scheme is achieved by monitoring the second-order harmonic component in q-axis current and the fault is detected by comparing these components with those in normal conditions. The linear interpolation method is employed to determine the harmonic data in normal operating conditions. As soon as the fault is detected, the operating mode is changed to identify a fault type using the phase current waveform. To verify the effectiveness of the proposed fault detecting scheme, a test motor to allow inter-turn short in the stator winding has been built. The entire control algorithm is implemented using DSP TMS320F28335. Without requiring an additional hardware, the fault can be effectively detected by the proposed scheme during operation so long as the steady-state condition is satisfied.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.2
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• pp.664-677
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• 2014

Wind energy has proven its viability by the emergence of countless wind turbines around the world which greatly contribute to the increased electrical generating capacity of wind farm operators. These infrastructures are usually deployed in not easily accessible areas; therefore, maintenance routines should be based on a well-guided decision so as to minimize cost. To aid operators prior to the maintenance process, a condition monitoring system should be able to accurately reflect the actual state of the wind turbine and its major components in order to execute specific preventive measures using as little resources as possible. In this paper, we propose a fault detection approach which combines cluster analysis and frequent pattern mining to accurately reflect the deteriorating condition of a wind turbine and to indicate the components that need attention. Using SCADA data, we extracted operational status patterns and developed a rule repository for monitoring wind turbine systems. Results show that the proposed scheme is able to detect the deteriorating condition of a wind turbine as well as to explicitly identify faulty components.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.4
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• pp.619-625
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• 2016

In this paper, we propose a new fault diagnosis monitoring system using gyro sensor-based angular velocity calculation for blades of the wind turbine system. First, the proposed system generates the angular velocity dataset for the rotation speed of the normal blade. Using the dataset, we estimate and evaluate the state of blades for the wind turbine by comparing the current state with the pre-calculated normal state. In the experimental results, the angular velocity of the normal state was higher than $360^{\circ}/s$ while that of the damaged blades was lower than $360^{\circ}/s$ and the standard deviation of the angular velocity was significantly increased.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.4
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• pp.330-335
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• 2013

Since real-time monitoring system like a fault early detection has been very important, infrared thermography technique as a new diagnosis method was proposed. This study is focused on the damage detection and temperature characteristic analysis of ball bearing using the non-destructive infrared thermography method. In this paper, for the reliability assessment, infrared experimental data were compared with the frequency data of the existing. As results, the temperature characteristics of ball bearing were analyzed under various loading conditions. Finally it was confirmed that the infrared technique was useful for real-time detection of the bearing damages.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.7
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• pp.611-617
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• 2015

In the development of a vibration-based condition monitoring system in gearbox, one of the most important research topics is a quantitative analysis and test of the effect of gear damage on vibration of gearbox. This paper presents the evaluation result of vibration condition indicator according to the gear tooth damage through the vibration test of gearbox. The dynamic load test was performed with high speed railway (KTX)'s gearbox. The vibration of gearbox was measured according to a rotational speed change with the common gear fault modes, such as pitting and tooth breakage. The characteristics and the possibility of applying of vibration condition indicator on condition monitoring system were analyzed. As a result, the value of most condition indicator is gradually increased with the severity of gear faults. The NA6 indicator shows a low variation with the rotational speed change and high sensitivity in accordance with the gear fault.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.11
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• pp.872-879
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• 2017

This work presents a cable fault monitoring system based on the differential frequency domain reflectometry using a compact impedance analyser which is composed of a direct digital synthesizer, an op amp and a gain/phase detector with a micro controller. The proposed system can replace expensive vector network analysers for frequency domain reflectometry and therefore be deployed in sensor networks for long term multi-point cable monitoring. Effectiveness of the system is experimentally confirmed by diagnosing the status of the power cable.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.2_2
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• pp.315-325
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• 2023

Recently, various dynamic risk analysis methods have been suggested for estimating the risk index by predicting the possibility of accidents and damage. It is necessary to maintain and support the safety system for responding to accidents by continuously updating the probability of accidents and the results of accidents, which are quantitative standards of ship risk. In this study, when a LNG leakage that may occur in the LN G Fuel Gas Supply System (FGSS) room during LN G bunkering operation, a reliability physical model was prepared by the change in monitoring data as physical parameters to estimate the accident probability. The scenario in which LNG leakage occur were configured with FT (Fault Tree), and the coefficient of the covariate model and Weibull distribution was estimated based on the monitoring data. The possibility of an LNG leakage, which is the top event of FT, was confirmed by changes in time and monitoring data. A method for estimating the LNG leakage based on the reliability physical analysis is proposed, which supports fast decision-making by identifying the potential LNG leakage at the accident.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.376-379
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• 2006

In this paper, stack voltage monitoring module is developed which monitor cell voltage of the fuel cell stack and transfer it to the main controller for monitoring fault and stopping drive when the trouble is happened in the fuel cell stack. Especially, the circuit, for monitoring each cell voltage of several hundreds cells in stack, is designed and analyzed. The connector is also developed for making wire harness simple and low cost because wire harness is complicated when the cells are connect each monitoring circuit.

• The Journal of the Acoustical Society of Korea
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• v.20 no.5
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• pp.21-27
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• 2001

Impulsive sound and vibration signals in gear system are often associated with their faults. Thus these impulsive sound and vibration signals can be used as indicators in condition monitoring of gear system. The traditional continuous wavelet transform has been used for detection of impulsive signals. However, it is often difficult for the continuous wavelet transform to identify spikes at high frequency and meshing frequencies at low frequency simultaneously since the continuous wavelet transform is to apply the linear scaling (a-dilation) to the mother wavelet. In this paper, the spike wavelet transform is developed to extract these impulsive sound and vibration signals. Since the spike wavelet transform is to apply the non-linear scaling, it has better time resolution at high frequency and frequency resolution at low frequency than that of the continuous wavelet transform respectively. The spike wavelet transform can be, therefore, used to detect fault position clearly without the loss of information for the damage of a gear system. The spike wavelet transform is successfully is applied to detection of the gear fault with tip breakage.