• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.616-619
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• 1995

This paper describes developement of on-line system for vibration signal analysis. In the power system, the main reason of transformer fault is due to a large amount of current by a short-circuit and a ground-fault. The electromagnetic force caused by fault-current deforms transformer windings and results in vibration pattern change. Therefore if the continuous on-line vibration monitoring on transformer is performed, an incipient failure can be detected. The developed system is composed of data acquisition devices, user interface program, signal processing program, diagnosis and trend analysis program, self diagnosis program and communication program.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.2
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• pp.73-79
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• 1988

A fault current in Simultaneous faults is calulated, which satisfies the reliability for expansion of power scale. New algorithm for analyzing fault current is developed, which calculates exactly thevnin equivalent impedance from fault point by cecomposing increment bus admittance matrix ( Ybus), and fault current is calculated by applying multiport theory. The signeficant results are as follows ` 1) When system fault changes system configulation, equivalent impedance can be calculated simply with this new algorithm. 2) Mutual coupling of transmission line can be calculated efficiently. 3) Simultaneous fault current is analyzed by applying multiport theory, which can be applicable to large scale systems.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.1
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• pp.113-117
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• 2011

As one of the countermeasures to solve the increase of the fault current in a power system, the superconducting fault current limiter (SFCL) has been noticed together with the development of a various types of SFCL, which has accelerated the researches to apply a SFCL into a power system. Among the developed SFCLs, the transformer type SFCL is expected to be available for adjusting the voltage and the current ratings of the SFCL. In this paper, the fault current limiting and the bus line‘s voltage sag suppressing effect by the transformer type SFCL were investigated and the case without the transformer type SFCL was compared as well. Through the analysis on the results of the short-circuit tests, the fault current limiting and the bus-line voltage suppressing characteristics of the transformer type SFCL could be confirmed to be effectively performed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.3
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• pp.504-510
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• 2016

In general, a fault locator is installed in Sub-Station of AT(Auto-transformer) feeding system to estimate the fault location and to protect the Korean AT feeding system. Since the line impedance characteristic is different to normal 3-phase transmission line, we need particular modification factors, which can be calculated using fault location recording data, to estimate the accurate fault location. Up to recently, forcible ground test has been used to calculate the modification factors of the fault locator. However, large amount of current is occurred when the forcible ground test is performed, and this current affects to adjacent equipments. Therefore, we proposed a novel calculation method of modification factors, arbitrary trip test, using boosting current of the operating electric train. Through several field test, we confirmed that modification factors for fault locator can be easily calculated by using proposed method. Moreover, we verified the accuracy and stability of the proposed calculation method.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.506-508
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• 2007

In this paper, the induction motor bearing fault diagnosis system using current signals which are measured by over-sampling method is presented. In the case of inverter fed motor drive unlike line-driven motor drive, that make a lot of noise which can cause a wrong fault signals because of PWM(pulse width modulation) voltage. So, the current signals for fault diagnosis need very precise and high resolution information, which means this system demand additional hardware such as low pass filter, high resolution ADC system and so on to use fault diagnosis system. Therefore, the proposed over-sampling method is expected to contribute to low cost fault diagnosis system even though previous inverter fed motor drive without any additional hardware. In order to confirm the presented algorithms, various experiments for bearing faults are tested and the line current spectrum of each faulty situation using park transformation is compared with a FFT results.

• Earthquakes and Structures
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• v.19 no.6
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• pp.445-457
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• 2020

An ultra-high voltage (UHV) transmission system has the advantages of low circuitry loss, high bulk capacity and long-distance transmission capabilities over conventional transmission systems, but it is easier for this system to cross fault rupture zones and become damaged during earthquakes. This paper experimentally and numerically investigates the seismic responses and collapse failure of a UHV transmission tower-line system crossing a fault. A 1:25 reduced-scale model is constructed and tested by using shaking tables to evaluate the influence of the forward-directivity and fling-step effects on the responses of suspension-type towers. Furthermore, the collapse failure tests of the system under specific cross-fault scenarios are carried out. The corresponding finite element (FE) model is established in ABAQUS software and verified based on the Tian-Ma-Qu material model. The results reveal that the seismic responses of the transmission system under the cross-fault scenario are larger than those under the near-fault scenario, and the permanent ground displacements in the fling-step ground motions tend to magnify the seismic responses of the fault-crossing transmission system. The critical collapse peak ground acceleration (PGA), failure mode and weak position determined by the model experiment and numerical simulation are in relatively good agreement. The sequential failure of the members in Segments 4 and 5 leads to the collapse of the entire model, whereas other segments basically remain in the intact state.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.9
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• pp.14-24
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• 2009

Memory cell array and peripheral circuits are designed for system on panel style frame buffer. Moreover, a parallel test methodology to test multiple blocks of memory cells is proposed to overcome low yield of system on panel processing technologies. It is capable of faster fault detection compared to conventional memory tests and also applicable to the tests of various embedded memories and conventional SRAMs. The various patterns of conventional test vectors can be used to enhance fault coverage. The proposed testing method is also applicable to hierarchical bit line and divided word line, one of design trends of recent memory architectures.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.4
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• pp.518-523
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• 2008

In this paper, we present the development of an intelligent diagnosis system for detecting faults of the transmission line. Based on the TFDR (Time-Frequency Domain Reflectometry), the fault detecting performs to measure the location of fault line. We analyze the reflected signal which is sent from the wire detecting system and classify the fault type of the wires by using intelligent diagnosis system. In order to analyze effectively, we construct the intelligent diagnosis system which is based on the fuzzy-bayesian algorithm. Finally, we provide the simulation results which are performed at transmission line to evaluate the feasibility and generality of the proposed method in this paper.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.3
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• pp.932-951
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• 2021

The effectiveness of testing in Model-based Testing (MBT) for Software Product Line (SPL) can be achieved by considering fault detection in test case. The lack of fault consideration caused test case in test suite to be listed randomly. Test Case Prioritization (TCP) is one of regression techniques that is adaptively capable to detect faults as early as possible by reordering test cases based on fault detection rate. However, there is a lack of studies that measured faults in MBT for SPL. This paper proposes a Test Case Prioritization (TCP) approach based on dissimilarity and string based distance called Last Minimal for Local Maximal Distance (LM-LMD) with Dice-Jaro-Winkler Dissimilarity. LM-LMD with Dice-Jaro-Winkler Dissimilarity adopts Local Maximum Distance as the prioritization algorithm and Dice-Jaro-Winkler similarity measure to evaluate distance among test cases. This work is based on the test case generated from statechart in Software Product Line (SPL) domain context. Our results are promising as LM-LMD with Dice-Jaro-Winkler Dissimilarity outperformed the original Local Maximum Distance, Global Maximum Distance and Enhanced All-yes Configuration algorithm in terms of Average Fault Detection Rate (APFD) and average prioritization time.

• Journal of the Korean Society of Safety
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• v.29 no.5
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• pp.47-53
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• 2014

Despite the automatic fire alarm system, according to the national fire data system of national emergency management agency, the fires account for 40,932 incidents, 2,184 injuries and about 430 billion won in property losses in 2013. Since the conventional automatic fire alarm system has several weaknesses related to electrical signal such as noise, surge, lighting, etc. Most fires are mainly caused by electrical faults, mechanical problem, chemical, carelessness and natural. The electrical faults such as line to ground fault, line to line fault, electrical leakage and arc are one of the major problems in fire. This paper describes the development of a novel real-time fire monitoring system algorithm including fault detection function which puts the existing optic smoke and heat detectors for fire detection with current and voltage sensors in order to utility fault monitoring using high accuracy DAQ measurement system with LabVIEW program. The fire detection and electrical fault monitoring with a proposed a new detection algorithm are implemented under several test. The fire detection and monitoring system operates according to the proposed algorithm well.