• Transactions of The Korea Fluid Power Systems Society
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• v.1 no.2
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• pp.1-7
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• 2004

In-process diagnosis is essential to achieve predictive maintenance in industrial plants. An in- process diagnosis method was proposed for hydraulic servo systems, which was based upon leakage flow measurement. Leakage due to servovalve wear was analysed and modeled mathematically far computer simulation work. The key idea of diagnosis algorithm is that when monitoring signals, such as servovalve input and load displacement are in steady states, the return-line flow of hydraulic servo systems can be regarded as null-leakage of servovalve. Virtual experiments were performed to ensure effectiveness of the proposed diagnosis method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.197-203
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• 2014

The technology to predict and prevent an accident of the cable system in power station is required. The techniques of inactivated diagnosis, partial discharge and $tan{\delta}$, have been adopted to diagnoze the operating characteristics of cables, but it is not so easy to find out problems in cables in an inactive state before the cable accident happens. In this paper, we did a research on the 6.6kV high-power cables, installed at Korean Western Power Station Co., Ltd. in order to diagonize the cables, playing a major role at the station. We have developed an equipment to measure an insulation resistance based on the temperature and current of the cable. By installing the system in a power station, we could find abnormal status for evaluation of the lifetime. In the short term, by analyzing the data, we apply the research result to the diagnosis and evaluation of the 6.6kV power cables. In the long run, however, we plan to reduce the cost of the installation and operation of cable systems at power stations.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.9
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• pp.18-24
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• 2007

When faults occur in the power equipment that is used a great deal in industrial sites, it may lead to fatal accidents that cause losses both economically and in manpower. In this paper, the effect of particle impact on the partial discharge of $SF_6$ gas was measured by simulating a partial discharge following the type of fault found in the GIS using $SF_6$ insulating gas as the insulating material. A spectrum analysis was performed on the radiate electromagnetic waves emitted upon partial discharge by using the UHF insulation diagnosis method. This subject of this study is insulation diagnosis by the measurement of radiate electromagnetic waves when particles exist in the GIS and power equipment insulated with $SF_6$ gas.

• Journal of Drive and Control
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• v.18 no.4
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• pp.92-97
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• 2021

• Journal of Drive and Control
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• v.18 no.4
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• pp.98-103
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• 2021

• Journal of Drive and Control
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• v.16 no.3
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• pp.94-102
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• 2019

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.276-278
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• 2000

In KwangYang steel works power system operation, the ON-LINE application of power system diagnosis technology is indispensable to not only power quality, but also stable operation and economical generation. In cases of stability constraint violation. stable power system operation is obstructed. Steel works power system is consist of 154kV transmission lines, and 345, 154, 22, and 6.6[KV] distributed lines, 5 numbers of substation, 17 units of generators. For this power system operation. loadflow program is developed. Database is tied with Windows GUI application, is designed, and is interfaced with this program. This program put up with loadflow solution of assembled MMI power system, and planed to diagnose of overloads or to imitate entrance, and isolation of equipment.

• 유공압시스템학회:학술대회논문집
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• 2010.06a
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• pp.56-61
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• 2010

Simulator is a development equipment which enables the ECU to operate in normal mode by simulating the interface signal between ECU and mechanical system electrically. Embedded simulator means simulation function is embedded in ECU firmware, hence the electrical signal interface is replaced by the substitution of information at system program level. This paper explains the development of embedded transmission simulator for the verification of TCU firmware function which covers shifting control and on-board diagnosis. The embedded simulation program is executed in TCU processor along with the TCU firmware and it provides TCU firmware with not only the speed information those are appropriate both in driving and shifting conditions, but also the fault detection signals. Experimental results show that the validity of embedded simulator and its usefulness to the TCU firmware development and verification.

• Journal of Welding and Joining
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• v.32 no.3
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• pp.102-107
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• 2014

Boiler equipment in power plant is always being operated in harsh conditions and severely exposed to the extreme environment of high temperature. Therefore periodically the state of devices should be checked, diagnosed, and analyzed to ensure the reliability of the equipment. Traditionally, such a diagnosis is based one or two physical properties of the sample taken from the equipment like hardness, microstructure, etc.. However, to enhance the confidence of the diagnosis, it is necessary to synthesize those properties together. This paper is to propose such a synthetic procedure for SA213-T12(1Cr-0.5Mo) which was developed to be used in $565^{\circ}C$ below condition. Creep test and accelerated degradation test were performed simultaneously, and the physical properties such as microstructure, tensile strength, yield strength, hardness, and indentation properties were measured. This paper proposes a method of determining the remaining life by quantitative comparison. It will provide the basis of evaluating life assessment more objective and reliable.

• Journal of Welding and Joining
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• v.31 no.5
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• pp.26-34
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• 2013

Boiler equipment in power plant is always being operated in harsh conditions and severely exposed to the extreme environment of high temperature. Therefore periodically the state of devices should be checked, diagnosed, and analyzed to ensure the reliability of the equipment. Traditionally, such a diagnosis is based one or two physical properties of the sample taken from the equipment like hardness, microstructure, etc.. However, to enhance the confidence of the diagnosis, it is necessary to synthesize those properties together. This paper is to propose such a synthetic procedure for T23 which was developed to be used in $569^{\circ}C/596^{\circ}C$ condition. Creep test and accelerated degradation test were performed simultaneously, and the physical properties such as microstructure, tensile strength, yield strength, hardness, and indentation properties were measured. This paper proposes a method of determining the remaining life by quantitative comparison. It will provide the basis of evaluating life assessment more objective and reliable.