Dependence of the Partial Discharge Characteristics of Ultra-high Voltage Cable Insulators on the Measuring Temperature

신종열,박희두,이강원,김원종,홍진웅 한국전기전자재료학회 2008 Transactions on Electrical and Electronic Material Vol.9 No.5

Cross linked polyethylene (XLPE) insulators are used as insulation in ultra-high voltage electric power cables. This study investigated the electrical properties of XLPE at different temperatures. The electrical properties of the changing tree phenomenon was examined as a function of temperature applied to the electrical conductors by measuring the partial discharge at 25 ˚C to 80 ˚C and applied voltages to the electrodes ranging from 1 kV to 40 kV. The activity of the partial discharge was examined at various temperatures using the K-means distribution. The results revealed the specimen at 80 ˚C to have the lowest inception voltage and breakdown voltage. In addition, the core of clusters was moved 0 ˚ and 180 ˚ at the positive region and 180 ˚ and 360 ˚ in the negative region in the K-means. The distribution of clusters was concentrated on the inception condition and spread out widely at the breakdown voltage.

에폭시 성형 점화코일의 인가전압에 따른 부분 방전 온도 의존성

신종열,홍진웅,Shin, Jong-Yeol,Hong, Jin-Woong 한국전기전자재료학회 2015 전기전자재료학회논문지 Vol.28 No.2

A gasoline engine automobile uses high voltage generation of the ignition coil, igniting and burning mixed fuel in the combustion chamber, which drives the engine. When the electronic control unit intermits a current supplied to the power transistor, counter electromotive force with a low voltage is generated by self induction action in the ignition primary coil and a high voltage is induced by mutual induction action with the primary ignition coil in the second ignition coil. The high voltage is supplied to the ignition plug in the combustion chamber, causing a spark, igniting the compressed mixed fuel. If a very small defect occurs inside the insulating material when a voltage is applied in said ignition coil, the performance of the insulation material will get worse and breakdown by a partial discharge of corona discharge. Thus, in this experiment, we are to contribute to improve the performance and ensure the reliability of the ignition coil by investigating partial discharge characteristics according to the change of voltage and temperature when a voltage is applied to the specimen of the epoxy molding ignition coil.

Effect of the Addition of Benzotriazole on the Streaming Electrification Properties in Transformer Oil

신종열,홍진웅 한국전기전자재료학회 2010 Transactions on Electrical and Electronic Material Vol.11 No.6

Accidents can occur as a result of streaming electrification when transformer oil is used as an insulating oil in large ultra-high voltage transformers. Methods for adding a streaming electrification inhibitor to reduce the streaming electrification has been studied extensively. In this paper, in order to develop a method for reducing streaming electrification effectively, 4 different specimens were prepared by the addition of benzotriazole (BTA) to a virgin specimen with constant stirring. The specimens were examined to determine the appropriate amount of BTA addition that would suppress the streaming electrification most effectively. The results showed that the streaming electrification characteristics of the specimen in the streaming transformer oil were best when the amount of BTA addition was about 10 ppm. The streaming electrification current was reduced by adding 30 ppm BTA until the temperature reached 65°C. The polarity of the streaming electrification current was negative when the temperature exceeded 65°C. Therefore, the streaming electrification current, which can be a cause of transformer accidents, can be suppressed in large ultra high voltage transformer oil. This paper reports on the optimal amount of BTA addition and the best conditions for controlling the streaming velocity of transformer oil.

침 전극 기울기에 따른 XLPE의 부분 방전 특성

신종열,안병철,홍진웅,Shin, Jong-Yeol,Ahn, Byung-Chul,Hong, Jin-Woong 한국전기전자재료학회 2015 전기전자재료학회논문지 Vol.28 No.1

The needle electrode is inserted into the cross-linked polyethylene(XLPE) which is the ultra high voltage cable for electric power. By changing the tilt of the needle electrode, we investigated how the void and the thickness of the insulating layer influence the partial discharge(PD) characteristics and the insulating breakdown. In order to investigate the PD characteristics, The XLPE cable was used to the specimens and the tungsten electrode was used with the needle electrode. And the inner semi-conductive layer material of XLPE cable was used with the negative electrode by bonding with the use of conduction tape. The size of the specimens was manufactured to be $16{\times}40{\times}30[mm^3]$. We confirmed the effect on changing the PD characteristics according to the changing voltage and the tilt of the electrode after applying the voltage on the electrode from 1[kV] to 40[kV] at room temperature. In the PD characteristics, it was confirmed that the PD current of air void specimens with tilt was unstable more than that of no void specimens with tilt. It was also confirmed that the breakdown voltage was decreased because the effect of air void is more active than the change of the needle electrode tilt in the specimen with air void inside the insulation.

Electrical Properties of the Epoxy Nano-composites according to Additive

신종열,박희두,최광진,이강원,이종용,홍진웅 한국전기전자재료학회 2009 Transactions on Electrical and Electronic Material Vol.10 No.3

The use of a filler material in epoxy composite materials is an essential condition for reducing the unit cost of pro-duction and reinforcing mechanical strength. However, the dielectric strength of insulators decreases rapidly due to interactions between the epoxy resin and filler particles. In contrast to existing composite materials, nano-composite materials have superior dielectric strength, mechanical strength, and enduring chemical properties due to an increase in the bond strength of the polymer and nano material. It is reported that nano-fillers provide new characteristics different from the properties of the polymer material. This study is to improve the insulation capa-bility of epoxy resins used in the insulation of a power transformer apparatus and many electronic devices mold. To accomplish this, the additional amount of nano-SiO2 to epoxy resin was changed and the epoxy/SiO2 nano composite materials were made, and the fundamental electrical properties were investigated using a physical prop-erties and an analysis breakdown test. Using allowable breakdown probability, the optimum breakdown strength for designing an electrical apparatus was determined. The results found that the electrical characteristics of the na-no-SiO2 content specimens were superior to the virgin specimens. The 0.4 wt% specimens showed the highest electrical properties among the specimens examined with an allowable breakdown probability of 20 %, which in-dicates stable breakdown strength in insulating machinery design.

산화마그네슘 첨가에 따른 나노컴퍼지트의 수명평가

신종열,정인범,홍진웅,Shin, Jong-Yeol,Jeong, In-Bum,Hong, Jin-Woong 한국전기전자재료학회 2015 전기전자재료학회논문지 Vol.28 No.6

Molded insulation materials are widely used from large electric power transformer apparatus to small electrical machinery and apparatus. In this study, by adding MgO with the average particle of several tens nm and the excellent thermal conductivity into molding material, we improved the problem of insulation breakdown strength decrease according to rising temperature in overload or in bad environmental condition. We confirmed the life evaluation by using the insulation breakdown and inverse involution to investigate the electrical characteristics of nano-composites materials. By using a scanning electron microscope, it is confirmed that MgO power with the average particle size of several tens nm is distributed and the filler particles is uniformly distributed in the cross section of specimens. And it is confirmed that the insulation breakdown strength of Virgin specimens is rapidly decreased at the high temperature area. But it is confirmed that the insulation breakdown strength of specimens added MgO slow decreased by thermal properties in the high temperature area improved by the contribution of the heat radiation of MgO and the suppression of tree. The results of life prediction using inverse involution, it is confirmed that the life of nano-composites is improved by contribution of MgO according to the predicted insulation breakdown strength after 10 years of specimens added 5.0 wt% of MgO is increased about 2.9 times at RT, and 4.9 times at $100^{\circ}C$ than Virgin specimen, respectively.

Performance of Three-Layered Organic Light-Emitting Diodes Using the Hole-Transport and Injection Layer of TPD and Teflon-AF, and the Electron-Injection Layer of Li2CO3 and LiF

신종열,김태완,김귀열,이수민,홍진웅 한국전기전자재료학회 2017 Transactions on Electrical and Electronic Material Vol.18 No.2

The performance of three-layered organic light-emitting diodes (OLEDs) was investigated using TPD hole-transportand injection layers, Teflon-AF, and the electron-injection layer of Li2CO3 and LiF. The OLEDs were manufactured in astructure of TPD/Alq3/LiF, TPD/Alq3/Li2CO3, and AF/Alq3/LiF using low-molecular organic materials. In three differentthree-layered OLEDs, it was found that the device with the TPD/Alq3/LiF structure shows higher performance inmaximum luminance, and maximum external quantum efficiency compared to those of the device with TPD/Alq3/Li2CO3 and TPD/Alq3/LiF by 35% and 17%, and 193% and 133%, respectively. It is thought that the combined LiF/Al cathode contributes to a reduced work function and improves an electrical conduction mechanism due to theelectron injection rather than the hole transport, which then increases a recombination rate of charge carriers.

Defect Diagnosis of Cable Insulating Materials by Partial Discharge Statistical Analysis

신종열,박희두,이종용,홍진웅 한국전기전자재료학회 2010 Transactions on Electrical and Electronic Material Vol.11 No.1

Polymer insulating materials such as cross linked polyethylene (XLPE) are employed in electric cables used for extra high voltage. These materials can degrade due to chemical, mechanical and electric stress, possibly caused by voids, the presence of extrinsic materials and protrusions. Therefore, this study measured discharge patterns, discharge phase angle, quantity and occurrence frequency as well as changes in XLPE under different temperatures and applied voltages. To quantitatively analyze the irregular partial discharge patterns measured, the discharge patterns were examined using a statistical program. A three layer sample was fabricated, wherein the upper and lower layers were composed of non-void XLPE, while the middle layer was composed of an air void and copper particles. After heating to room temperature and 50°C and 80°C in silicone oil, partial discharge characteristics were studied by increasing the voltage from the inception voltage to the breakdown voltage. Partial discharge statistical analysis showed that when the K-means clustering was carried out at 9 kV to determine the void discharge characteristics, the amount discharged at low temperatures was small but when the temperature was increased to 80°C, the discharge amount increased to be 5.7 times more than that at room temperature because electric charge injection became easier. An analysis of the kurtosis and the skewness confirmed that positive and negative polarity had counterclockwise and clockwise clustering distribution, respectively. When 5 kV was applied to copper particles, the K-means was conducted as the temperature changed from 50°C to 80°C. The amount of charge at a positive polarity increased 20.3% and the amount of charge at a negative polarity increased 54.9%. The clustering distribution of a positive polarity and negative polarity showed a straight line in the kurtosis and skewness analyses.

동산의 이중매매와 배임죄

신종열 사법발전재단 2011 사법 Vol.1 No.16

This paper is about supreme court en banc decision 2008Do10479 rendered on January 20, in 2011. The subject decision is the first ruling where the Court concluded that 'breach of trust‘’ is not applied to double selling of real property in principle. The Supreme Court had made it clear that after receiving some proportion of money out of total payment in advance, the criminal method of trust of breach shall be applied to double selling the property to another. At the same time it took the position that breach of trust shall or may apply to double transfer of various types of properties like bond, license or permission. On the contrast to the previous rulings, the subject decision ruled that the seller of movable properties is not the one who is in charge of doing affairs for the buyer of that properties even after the seller received a certain proportion of payment. Therefore breach of trust shall not be applied to the case. The decision is notable as it is against the opinion of majority scholars who argue that breach of trust should applied to the double selling of movable properties as they have similar structure with that of real properties. Especially, the subject decision provides various perspective and logical grounds regarding the meaning and purpose of the decision on the issue with majority opinion and dissenting opinion that run to opposite direction. It also deals with double selling or transfer which have not been seriously discussed. Adding significance to the decision, it also provide prediction on the supreme court’s opinion regarding interpretation and application of criminal law which regulates private transaction. This paper examines whether it is appropriate to differentiate double selling of movable properties to that of real properties, which is one of points at the issue, and deals with the grounds of argument that the supreme court explained to support logic of the decision. 이 글은 대법원 2011. 1. 20. 선고 2008도10479 전원합의체 판결에 대한 평석이다. 대상판결은 동산 이중매매 행위는 원칙적으로 배임죄에 해당하지 않는다고 선언한 첫 판례이다. 대법원은 중도금 수령 이후의 부동산 이중매매 행위가 배임죄에 해당한다는 입장을 확고히 정립하고 있을 뿐만 아니라 채권, 면허ㆍ허가권 등 다양한 재산의 이중양도 또는 이중매매에 관하여 배임죄의 성립을 긍정하거나 긍정할 수 있다는 입장을 취해 왔다. 그런데 대상판결은 동산 매도인은 중도금 수수 이후에도 매수인에 대한 관계에서 그의 사무를 처리하는 자에 해당하지 않는다고 하여 동산 이중매매로 인한 배임죄의 성립을 부정하였다. 이는 동산 이중매매를 부동산 이중매매와 동일한 구조로 파악하고 동산 이중매매에 대하여 배임죄의 성립을 긍정하는 학계의 다수설의 입장과 배치되는 것이라는 점에서 주목할 만하다. 특히 대상판결의 다수의견과 반대의견은 기존에 심도 있게 다루어지지 않은 부동산 등의 이중매매 또는 이중양도 관련 판례의 취지와 의미에 관한 다양한 시각과 논증을 제공하고 있을 뿐만 아니라, 사적 거래를 규율하는 형벌법규의 해석ㆍ적용에 관한 대법원의 향후 기본입장을 가늠해 볼 수 있는 논쟁도 전개하고 있다는 점에서, 대상판결에 상당한 의미를 부여할 수 있다고 생각된다. 이 글에서는 대상판결이 다루고 있는 논점 중에서 동산 이중매매를 부동산 등의 이중매매 또는 이중양도와 달리 취급하는 것이 적절한지, 그 논거는 무엇인지 등의 문제를 주로 검토해 보았다.

고차구조 변화에 따른 저밀도폴리에틸렌 박막의 전기적 특성

신종열,신현택,이수원,홍진웅 한국산업안전학회 2002 한국안전학회지 Vol.17 No.4

The electrical properties of polyethylene are changed by the superstructure. Such crystalline polymer as polyethylene or polypropylene changes crystallinity and products spherulite or trans-crystal when it is cooled slowly. In this study, after thermal treatment of LDPE at 100[℃], in silicone oil for an hour, we made specimens in order of slow cooling, water cooling, quenching according to cooling speed. Also, to study the influence of electrical properties due to the superstructure change, we analyzed physical properties and performed dielectric breakdown experiments using DC and impulse voltage. Moreover we measured space charges in bulk using Laser Induced Pressure Pulse(LIPP)method. Trap level of specimen is 0.064[eV] at the low temperature region, 0.31[eV] at the high temperature region in DC dielectric strength, 0.03[eV] at the low temperature region 0.0925[eV] at the high temperature region in impulse dielectric strength. As its result shows that the quantity of charges induced from the electrode surface increases with applied voltage time, and the distribution of space charges in samples increases the quantity of charges in proportion to applied voltage.