• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1740-1742
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• 1998

This paper describes the technique of deterioration diagnosis for ZnO element. Due to the non-linear resistance of ZnO block, the total leakage current contains harmonics when arrester deteriorated. The most significant harmonics is the 3rd order component. So, it can be used as an indicator of the arrester condition. An iron core, which has a very high relative permeability, is used for increasing detection sensitivity and the 3th order harmonics of leakage current was detected by band-pass circuit. And we have verified the reliability and performance of the sensing device through several laboratory tests.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.12
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• pp.562-567
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• 2003

Lightning arresters are deteriorated by repetition of protective operation against overvoltages or impulse currents in environments of its use. If a deteriorated arrester is left in power lines, it can lead to an accident such as a line to ground fault even in a normal system. Therefore, it is necessary to eliminate the deteriorated arrester in advance by checking the soundness of arresters on a regular basis, and to ensure the reliability of power systems by preventing accidents. Various deterioration diagnostic techniques and devices are suggested, and most of which measure leakage current components as an indicator of arrester ageing. However, the techniques based on the magnitude of leakage current measure simply RMS or peak value of leakage current components and do not provide detailed information needed in the diagnosis. In this study, we found that the wave height distributions of the total leakage currents are remarkably changed or a new wave height are produced with the progress of arrester deterioration. To propose a new technique for the diagnosis, we designed a leakage current detection unit and an analysis program which can measure leakage current magnitudes and analyze wave height distributions. From the experimental results, we confirmed that the proposed technique by analyzing the wave height distribution can simply diagnose the mode of defects such as a partial damage and an existence of punctures in arresters as well as deterioration of arresters.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1082-1084
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• 1998

In this paper, we developed a diagnosis device for ZnO arrester to detect on-line leakage current and acquire data from the power distribution system. The arrester is important power equipment used in power transmission and distribution systems to protect the generator and the main transformer from surge and overvoltage. First of all we developed a diagnosis device for ZnO arrester leakage current. And then we detect the total leakage current by the developed device without disconnecting the arrester ground wire and analysis the 3rd order harmonic by Fast Fourier Transform(FFT) to diagnose the ZnO arrester deterioration. With measuring the total current and the resistive current of power distribution system in operation, we analysis the trend of resistive current component in the total leakage current. We expect the result will be promote the method to protect electrical utility and customer from accident.

• Journal of the Korean Society for Railway
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• v.7 no.4
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• pp.307-311
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• 2004

Arresters are the best protective device on electrical power systems against transient overvoltages generated by lightning and/or switching operation. Nonetheless, arresters are deteriorated by absorption of moisture in the environments of its use, repetition in the protective operation to overvoltages, and some defects at manufacturing. It is therefore important to estimate the electrical characteristic changes of ZnO blocks. In this paper, an accelerated ageing test by a standard lightning impulse current was carried out to extract parameters needed for arrester diagnosis, and leakage current components were measured. Total energy applied to the ZnO blocks at each time is about 1,050[J] in 8/20[${\mu}\textrm{s}$] impulse current. From the experimental results, we proposed electrical parameters and leakage current level to diagnose arrester soundness.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.2
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• pp.313-318
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• 2014

In the last couple of decades industrialization and technological development has not only increase in the scale of electrical facilities and it has become more and more complicated and diversified. Furthermore, fires in the electrical transformers, like those that have knocked out power in the country in the past years, are likely to become more common as utility systems begin to show their age. The importance of preventing electrical accidents can never be overemphasized and for this reason, supply of on-line diagnosis system combining information and communication technology(ICT) for the customer's electrical facilities has been increasing recently. The major advantage of on-line diagnosis system is that the device's potential problems could be detected early before a serious deterioration or breakdown occurs. In this paper, We estimated the benefit from the investment in the right of present value of sales, success rate of commercialization regarding R&D investment for development and commercialization of on-line diagnosis technology targeting customer electrical facilities. As a result, the net value added of 29.7 billion won and the increased profit by roughly 7.52 precent are expected.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.6
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• pp.85-92
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• 2000

This paper has developed the system that can monitor the distribution transformers(pole and pad) using simplified deterioration detecting sensor in oil and wireless data communication. This system is made up by deterioration detecting sensor, oil level measuring system, deterioration measuring system and communication unit. To prove the usefulness of the system, the paper compared and analyzed the system with the existed system, and after studying the correlation of the both, the result proved goodness of the new system. The proposed monitoring system, when it is used on the pole and pad transformer, would make the reliable diagnoses possible with less rate.

• Journal of the Korean Society of Safety
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• v.33 no.2
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• pp.21-27
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• 2018

The expansion and stable operation of electric power facilities are important factors with development of industrial facilities in modern society. In high-voltage equipment such as GIS, the insulation characteristics may be deterioated by environment-friendly gas adaption and miniaturization. There is also the possibility of accidents due to insulation breakdown due to the deterioration of power facilities. Therefore, it is necessary to extend the diagnosis system to continuously monitor the danger signals of these power equipment and to prevent accidents. Most of the internal defects in the GIS system are conductive particles, floating electrode defects, protrusion defects, and the like. In this case, a partial discharge phenomenon is accompanied. These partial discharge signals occur irregularly and various noise signals are included in the field, so it is difficult to evaluate the reliability in the development of the diagnostic system. In this paper, a study was made on equipment capable of generating a partial discharge simulated signal that can be adjusted in size and frequency to be applied to a diagnostic device by electromagnetic wave detection method. The PD simulated pulse generator consists of a user interface module, a high-voltage charging module, a pulse forming circuit, a voltage sensor and an embedded controller. In order to simulate the partial discharge phenomenon similar to the actual GIS, a discharge cell was designed and fabricated. The application of the prototype pulse generator to the commercialized PD diagnosis module confirmed that it can be used to evaluate the performance of the diagnostic device. It can be used for the development of GIS diagnosis system and performance verification for reliability evaluation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.5
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• pp.111-116
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• 2022

The causes of motor burnout include overload, phase loss, restraint, interlayer short circuit, winding ground fault, instantaneous overvoltage, and the rotor contacting the stator, leading to insulation breakdown, leading to breakdown or electrical accidents. Therefore, equipment failure causes not only loss due to cost required for equipment maintenance/repair, but also huge economic loss due to productivity decrease due to process stop because the process itself including the motor is stopped. The current level of technology for diagnosing motor failures uses vibration, heat, and power analysis methods, but there is a limit to analyzing the problems only after a considerable amount of time has passed according to the failure. Therefore, in this paper, a device and algorithm for measuring insulation resistance using DC AMP signal was applied to an industrial motor to solve this problem. And by following the insulation resistance state value, we propose a diagnosis of deterioration and failure of the motor that cannot be solved by the existing method.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2155-2157
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• 1999

This paper describes a new measurement method of resistive current and the technique of deterioration diagnosis for ZnO element. The consequence of current increasing (resistive current) with time is the eventual attainment of a state of thermal instability that may lead to arrester failure. So, it is very important to measure a leakage current of ZnO arrester installed at on-state. For the high-precision and more reliability, an iron core, which has a very high relative permeability, was used for increasing detection sensitivity, and we also used the personal computer for the data storage and program and analysis. And we have verified the reliability and performance of the sensing device through several laboratory tests.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.102-110
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• 2023

PSC-I girder bridges constitute the largest proportion among highway bridges in Korea. According to the precision safety diagnosis data for the past 10 years, approximately 41.3% of the PSC-I bridges have been graded as C. Furthermore, with the increase in the aging of bridges, preemptive management is becoming more important. Damage and deterioration to the deck and girder with a long replacement cylce can have considerable impacts on the service and deterioration of a bridge. In addition, the high rate of device damages, including expansion joints and bearings, necessitates an investigation into the influence of the device damage in the structural members of the bridge. Therefore, this study defined representative PSC-I girder bridges with single and multiple spans to evaluate heterogeneous damages that incorporate the damage of the bridge member and device with the deterioration of the deck. The heterogeneous damages increased a crack area ratio compared to the individual single damage. For the single-span bridge, the occurrence of bearing damage leads to the spread of crack distribution in the girder, and in the case of multi-span bridges, expansion joint damage leads to the spread of crack distribution in the deck. The research underscores that bridge devices, when damaged, can cause subsequent secondary damage due to improper repair and replacement, which emphasizes the need for continuous observation and responsive action to the damages of the main devices.