• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제54권12호
• /
• pp.578-584
• /
• 2005

This paper describes development of management software for transformers based on artificial intelligent analysis technology of dissolved gases in oil. Fault interpretation using the artificial intelligent analysis is performed by the artificial neural network and a rule based on the analysis of dissolved gases. The used gases are acetylene($C_{2}H_{2}$), hydrogen($H_2$), ethylene($C_{2}H_{4}$), methane($CH_4$), ethane($C_{2}H_{6}$), carbon monoxide(CO) and carbon dioxide($CO_2$). This software is mainly composed of gases input, fault's causes, expected fault's phenomena in detail, the decision on maintenance as well as report and gas trend windows. It is indicated that this is very powerful software for the efficient management of oil-immersed transformers using data analysis of gas components.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 제37회 하계학술대회 논문집 전기설비
• /
• pp.43-44
• /
• 2006

Characteristics of hydrogen sensors for realization of transformer diagnosis system was studied, sensors used in this work are commercialized for detecting hydrocarbons or hydrogen gases. Based on the experimental results, the sensing characteristics of A company showed the high value even at the lower concentration of 20ppm, and it showed a saturation tendency with increasing it above 500ppm. In the case of B company, it showed the linear characteristics from 20ppm to 7000ppm. In addition, the output acquired from C company was amplified by external circuits due to its low output, and its adequate operation region was above 500ppm. Therefore, it is likely that these sensors are possible to apply for realization of transformer diagnosis system due to the different sensing characteristics of these sensors.

• 조명전기설비학회논문지
• /
• 제20권8호
• /
• pp.6-14
• /
• 2006

본 논문은 TFT-LCD(Thin Film Transistor Liquid Crystal Display) PECVD(Plasma Enhanced Chemical Vapor Deposition) 장비 공정용 챔버(Chamber) 세정을 위한 새로운 플라즈마 세정방법에 적합한 플라즈마 발생방법과 플라즈마 발생을 위한 고주파 전원장치의 전력회로에 관한 연구이다. 세정에 요구되는 고밀도 플라즈마는 안테나 형태의 기존 ICP(Inductively Coupled Plasma) 방식에 강자성체인 페라이트 코어를 적용하므로 써 $1{\times}10^{11}[EA/cm^3]$이상의 고밀도 플라즈마 발생을 가능하게 하였다. 플라즈마 발생을 위한 400[kHz] 고주파 전력 변환장치의 경우 범용 HB(Half Bridge) 인버터 방식을 적용하여 플라즈마 부하에서도 안정적인 영전압 스위칭 동작을 확인 하였다. 변압기 직렬결합 방식을 사용한 10[kW] 고출력을 통해 $A_r$과 $NF_3$가스 분위기하에서 플라즈마의 밀도와 $NF_3$가스 분해율을 측정하므로서 고주파 전력 변환 장치의 성능을 입증하였다.

• 한국재료학회지
• /
• 제4권3호
• /
• pp.312-318
• /
• 1994

이 논문은 절연유를 정제하여 $SF_6$ 가스를 용해시켰을 때 절연유의 수십 MHz대의 고주파 절연파괴 전압과 유전특성에 관해서 연구한 것이다. 1)절연유에서의 고주파 전류는 전압의 1/2승에 거의 비례하여 증가한다. 2)전원주파수가 증가함에 따라 고주파 절연파괴는 주파수의 제곱에 역비례하여 감소하는 현상을 나타내고 AC절연파괴의 전압때보다 약 35%정도가 감소한다. 3) 용해된 기체의 압력을 증가시킴에 따라 고주파 절연파괴 전압은 원만하게 증하한다. 4)전원주파수의 증가에 따른 유전정접(tan $\delta$)은 거의 지수 함수적으로 증가하고 유전률($\varepsilon$)은 [0.6% MHZ]의 기울기로 삼소하는 경향을 나타낸다. 5) $SF_6$ 가스를 용해시켰을때 절연파괴 특성은 Air 또는 Ar을 용해시켰을 때 보다 약 25% 정도 향상되는 특성을 나타낸다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2015년도 제46회 하계학술대회
• /
• pp.447-448
• /
• 2015

In order to looking for method of detecting inner fault of a 154kV GIT(Gas Insulated Transformer), it was considered that diagnosis partial discharge(PD) in UHF band and that analyze the ingredients of SF6 insulating gas. UHF PD diagnosis that is optimized to GIS was considered unsuitable through checking of inner part of a transformers which PD is detected excessively. The method analyzing the content of six kinds of gas(SOF2, SO2F2, etc)was decided through analysis of chemical degradation and combination process and discharge experiment. With the result applying this method to analyze the content of insulated gas of eighty five Gas Insulated Transformers.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제50권11호
• /
• pp.556-562
• /
• 2001

Spacer is used between main tank and auxiliary tank for on load tap changer in gas insulated power transformer. This paper deals with electrical design of spacer and discusses different analysis method of between 2D FEM(finite element method) and 3D FEM. To design spacer, we modeled structure of two kind of coaxial cylinders of spacer conductors and analysised electric field of spacer at impulse and induced test voltage condition. Spacer has 13 conductors and electric field was changed according to arrangement of conductors. We could find out arrangement of conductors at which electric stress is minimum. And this arrangement was satisfied with actual test conditions.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제50권3호
• /
• pp.115-121
• /
• 2001

This paper deals with the electrical insulation design of a gas insulated power transformer based on extra turns method satisfying the impulse test performed in the worst condition. The calculation of electrical strength in insulation structure was done by 2D finite element method. The gas insulated power transformer was manufactured by selecting the optimum arrangement among design results. the validity of the design result is verified by the impulse test of manufactured machine.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
• /
• pp.374-376
• /
• 2001

In this paper, we developed the fault diagnostic expert system of silicone-immersed transformer using dissolved gas analysis. The knowledge base module consists of the knowledge using the rule: if Then . The inference engine uses the fuzzy rule for the management of uncertainty of the boundary and rule and derivate the Belief and Plausibility of the normality and fault using Dempster-Shafer theory. The expert system is connected to the database and it can manages the history of gas-data of the transformer.

• 전기학회논문지P
• /
• 제65권3호
• /
• pp.188-193
• /
• 2016

It has been proven that the dissolved gas analysis (DGA) is the most effective and convenient method to diagnose the transformers. The DGA is a simple, inexpensive, and non intrusive technique. Among the various diagnosis methods, IEC 60599 has been widely used in transformer in service. But this method cannot offer accurate diagnosis for all the faults. This paper proposes a fault diagnosis method of oil-filled power transformers using DGA and Intelligent Probability Model. To demonstrate the validity of the proposed method, experiment is performed and its results are illustrated.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
• /
• pp.574-574
• /
• 2005

To found out the degradation characteristic of transformer insulation, insulation material was depisited into transformer oil and heated. Due to the thermal stress which added to insulation, the density of carbon dioxide which included in transformer oil was mesured by using the gas density detection equipment of gas sensor and air circulation method. As a result, it didn't match with the transformer supervision standard. But it was found that as thermal stress increased, the density of carbon dioxide propertionally increased.