• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.304-309
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• 1991

We introduce the trend, of several countries, to the gas insulated transformer recently coming into the spot light by the advantages of less weight, GIS-lization, low noise level and easiness to decrease environmental pollutions, and the insulating gases. the cooling media and the insulating materials used for transformer. Hereinafter, additively the design of proto type $SF_6$ gas insulated transformer (insulation, cooling), which was developed by us(HICO) from 1987. 2 through 1990. 3, the manufacturing processes(leak protection, pressure, drying of main body), the accessories, the protective system, the cooling system, the method and the results of test and the evaluation of economics compared with conventional oil-filled transformer are represented.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.87-90
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• 2004

This paper describes development of power transformer maintenance system using intelligent dissolved gases in oil analysis. The used gases are acetylene(C2H2), hydrogen(H2), ethylene(C2H4), methane(CH4), ethane(C2H6), carbon monoxide(CO) and carbon dioxide(CO2). The rule and neural network based gas analysis methods are used for artificial intelligent diagnosis. It is indicated that this program is efficient for diagnosis of oil immersed transformers diagnosis from application of gas analysis data of serviced transformer which has local overheating

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.1
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• pp.31-36
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• 2000

To enhance the fault diagnosis ability for the dissolved gas analysis(DGA) of the power transformer, this paper proposes a learning vector quantization(LVQ) for the incipient fault recognition. LVQ is suitable expecially for pattern recognition such as fault diagnosis of power transformer using DGA because it improves the performance of Kohonen neural network by placing emphasis on the classification around the decision boundary. The capabilities of the proposed diagnosis system for the transformer DGA decision support have been extensively verified through the practical test data collected from Korea Electrical Power Corporation.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.141-143
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• 2006

Dissolved gas analysis (DGA) is widely used to detect incipient faults in oil-filled electrical equipment. KEPCO make a rule of DGA in 1985. They have been diagnosing power transformer using their DGA criteria. In this paper, we analysis the result of DGA data about transformer in the substation. We try to find out what is cause of an error in DGA diagnosis considering accuracy in extracting gases from mineral oil in transformer. The carbon-monoxide was primary reason of warning in DGA data. We specially consider that aging is a cause of generating of carbon-monoxide in power transformer.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.159-163
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• 1989

The various degradation phenomena, such as the evolution of gases, tan $\delta$, moisture content and total acid number in power transformer insulation oil, have been measured and analyzed. Mineral oil has been degraded at laboratory by the forced thermal stress of $60^{\circ}C$ and $90^{\circ}C$ respectively. Thermal aging oil has been degraded about 17, 34, 72 days. Also, we extracted insulation oil from working transformers. We measured gases dissolved in samples, tan $\delta$, moisture content, total acid number. Activation energy and resistivity is calculated from them. It is found that gases and tan $\delta$ increases as partial discharge and total acid number increases and that conductivity of the sample increases as activation energy increases.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1676-1678
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• 2001

In general, power demand is on an increasing trend as industries have made rapid strides. Power transformer is the most important equipment in substation for this reason. Transformer trobles go with blackout, expensive repair costs and huge economic losses. Therefore it is important to find the quick detection of incipient fault for the least losses. There have been gas, partial discharge, temperature, OLTC, fan and pump diagnosis for preventive techniques by present. Specially gas analysis has been adapted for a long time and proved as confident method. In this paper, we analysed the fault causes of used power transformer. The insulation faults was occupied 40% of inquired 152 faults from 1991 to 2000. This study presents the developed algorithm and expert system for finding abnormal status within transformer. We used the Element Expert tool developed Neuron DATA Inc.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.93-96
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• 2004

초고압 GIS(Gas Insulated Substation, 가스절연변전소)는 변압기와 더불어 송변전기기 중에서 가장 중요한 2가지 품목 중의 하나이며, 도시의 과밀화, 디지털 경제사회로 이행함에 따른 고품질 전기수요로 인한 전력공급의 신뢰도 향상의 필요성, 도시미관 개선 및 친환경적인 설비요구 등의 요인에 의해 그 중요성은 더욱 커질 전망이다. 또한 가까운 장래에 도래할 것으로 전망되는 전력산업의 IT화 시대와 미주 및 유럽 지역에서의 송변전 설비의 낙후 및 교체시기 등을 고려해 볼 때에 GIS 분야의 중요성은 더욱 부각되고 있다. 본 논문에서는 초고압 GIS 관련 기술 국내외 연구개발동향을 분석해보고자 한다.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.97-100
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• 2004

초고압 GIS(Gas Insulated Substation, 가스절연변전소)는 변압기와 더불어 송변전기기 중에서 가장 중요한 2가지 품목 중의 하나이며, 도시의 과밀화, 디지털 경제사회화에 따른 고품질 전기수요로 인한 전력공급의 신뢰도 향상의 필요성, 도시미관 개선 및 친환경적인 설비요구 등의 요인에 의해 그 중요성은 더욱 커질 전망이다. 또한 가까운 장래에 도래할 것으로 전망되는 전력산업의 IT화 시대와 미주 및 유럽 지역에서의 송변전설비의 낙후 및 교체시기 등을 고려해 볼 때에 GIS 분야의 중요성은 더욱 부각되고 있다. 본 논문에서는 초고압 GIS의 주요부품에 관해 조사된 특허정보를 중심으로 과거의 기술흐름과 최근의 기술동향, 출원인 분석을 통한 기술의 우위현황 및 기술의 주요 분포도 등을 도식화된 그래프를 이용하여 다각적으로 분석하고자 한다.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.11
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• pp.569-574
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• 2001

In this paper, we described the new IEC method with fuzzy theory for detecting abnormal causes within transformer. The proposed technique presented the solution of limitation in case of lying nearly boundary conditions and not having codes for measured gas values in IEC code. Also, we proved the confidence of diagnosed results in the use of the gases values in real fault transformers.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1019-1021
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• 1999

In this paper, we describe the design and appliance of the preventive diagnostic expert system of gas in oil for power transformer. This expert system is developed to use expert system development tool; Element Expert (NEURON DATA Inc.) Analysis is developed by four diagnose methods. In first, the standard of KEPCO is applied. It classifies the state of transformer by four level: Normal, warning, abnormal and danger. And the others are gas pattern methods, IEC code method, and Dornen & Roger Ratio method and applied later. These latter methods analyse the cause of result. Inference engine was designed with Element Expert. In last, we operate the system with sample data and we can obtain the correctly inferred result for the state of transformer.