• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.539-540
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• 2006

In this paper, We examine that characteristics of formative electret with polymer film and electric charge storage using grid corona discharge. compound polymer of fluorine resin used for material in electret because of high electric charge accumulation, excellent electrical and physical characteristic. All experiments were carried out with circular samples of $Teflon^(R)FEP$ film, 12.5[${\mu}m$] thick. As experiment variables, we used voltage, electrode thickness, discharge electrode gap, and discharge time. According to this variables, we studied on characteristics of formative electret and electric charge storage. Additionally we make a comparative study of the result between the grid corona discharge and needle electrode discharge.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 추계학술대회논문집
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• pp.81-84
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• 2000

In this paper, we have the investigated the Influence of Filler Shape on Dielectric & Electric Charge-Discharge Properties of Filled Epoxy Resin. In the low frequency range from 50Hz to a few kHz, the maginitude of tan$\delta$ become larger in the order, NON, RAS, SAS, SCS. The electrical Discharge of RAS measured for 60 min, decreased after 10$^2$∼10$^3$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.81-84
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• 2000

In this paper, we have the investigated the Influence of Filler Shape on Dielectric & Electric Charge-Discharge Properties of Filled Epoxy Resin. In the low frequency range from 50Hz to a few kHz, the magnitude of tan$\delta$ become larger in the order, NON, RAS, SAS, SCS. The electrical Discharge of RAS measured for 60 min, decreased after 10$^2$∼10$^3$.

• 융복합기술연구소 논문집
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• 제11권1호
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• pp.19-23
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• 2021

These days, sales of battery electric vehicles have been rapidly increasing due to the strict CO₂ regulations. However, since it take too long to measure the energy economy of electric vehicles, it has been required to improve the procedure of energy economy measurement. In order to improve this problem, the present study analyzed the battery charge/discharge pattern according to the changes in battery SOC (state of charge). In general, the energy economy test is started with a battery SOC charged to 100 %. However, it was identified that when the battery is fully charged, it can actually be charged over the 100 % (e.g., 100.5 %). This can induce errors in the energy economy measurement. Therefore, the present study recommend to start the test at SOC 99.9 %. The regenerative braking was partly restricted for the SOC over 90 %. This made it difficult to estimate the overall energy economy of the electric vehicle. However, it was identified that there was no change in the battery charge/discharge characteristics under the SOC 90 %. Therefore, the energy economy test can be shortened by predicting the overall energy economy through a short mileage test.

• Journal of Electrical Engineering and Technology
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• 제10권2호
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• pp.647-652
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• 2015

A fully coupled finite element analysis (FEA) technique was developed for analyzing the discharge phenomena and dielectric liquid flow while considering surface charge density effects in dielectric flow guidance. In addition, the simulated speed of surface charge propagation was compared and verified with the experimental results shown in the literature. Recently, electrohydrodynamics (EHD) techniques have been widely applied to enhance the cooling performance of electromagnetic systems by utilizing gaseous or liquid media. The main advantage of EHD techniques is the non-contact and low-noise nature of smart control using an electric field. In some cases, flow can be achieved using only a main electric field source. The driving sources in EHD flow are ionization in the breakdown region and ionic dissociation in the sub-breakdown region. Dielectric guidance can be used to enhance the speed of discharge propagation and fluidic flow along the direction of the electric field. To analyze this EHD phenomenon, in this study, the fully coupled FEA was composed of Poisson's equation for an electric field, charge continuity equations in the form of the Nernst-Planck equation for ions, and the Navier-Stokes equation for an incompressible fluidic flow. To develop a generalized numerical technique for various EHD phenomena that considers fluidic flow effects including dielectric flow guidance, we examined the surface charge accumulation on a dielectric surface and ionization, dissociation, and recombination effects.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권5호
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• pp.385-390
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• 1999

Surface corona discharge characteristics of a dc corona charged ferroelectric pellet barrier have been investigated experimentally. Electric charges stored on the surfaces of the ferroelectric pellets by a dc corona discharge provide partial electric fields on the surfaces of the ferroelectric pellets, which could generate surface corona discharges on the ferroelectric pellets. This system utilizes both the surface discharges on the ferroelectric pellet barrier and the corona discharge between corona tip and mesh electrode. Positive and negative dc voltages were applied to the tip to generate partial discharges, and corona currents were estimated to investigate the buildup charge on ferroelectric pellets as a function of the applied time and the charge relaxation time constants of ferroelectric pellets. As a result, in the case of the negative corona discharge with the ferroelectric pellet barrier, the mean corona current and ozone generation increase greatly, and the surface discharges on the ferroelectric pellets can be fenerated efficiently. It is also found that, charge relaxation time, dielectric constants offerroelectric pellets, polarity of applied voltage and applied time affected to the surface discharges among the ferroelectric pellets.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.2089-2098
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• 2015

With the continuous development in insulation of electrical equipment design, the reliability of the system has been enhanced. However, in the manufacturing process and during operation under continues stresses introduce local defects, such as voids between interfaces that can responsible to occurrence of partial discharge (PD), electric field distortion and accumulation of charges. These defects may lead to localize corrosion and material degradation of insulation system, and a serious threat to the equipment. A model of three layers of PI film with air gap is presented to understand the influence of interface and voids on exploitation conditions such as strong electrical field, PD activity and charge movement. The analytical analysis, and experimental results are good agreement and show that the lose contact between interfaces accumulate more residual charges and in consequences increase the electric field intensity and accelerates internal discharges. These residual charges are trapped charges, injected by the electrodes has often same polarity, so the electric field in cavities increases significantly and thus partial discharge inception voltage (PDIV) decreases. Contrary, number of PD discharge quantity increases due to interface. Interfacial polarization effect has opposite impact on electric field and PDIV as compare to void.

• 한국컴퓨터정보학회논문지
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• 제15권8호
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• pp.157-161
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• 2010

대도시 대기오염의 대부분이 자동차 배출가스에 의해서 이루어지고 있으며, 세계적으로 환경오염에 대한 규제수준이 점차 강화되고 있어 저공해의 환경 친화적인 자동차의 개발과 보급이 요구되고 있으며, 고유가 시대에서 이미 국내 외에서 개발 양산중인 하이브리드 자동차의 급속한 시장 확대가 예상된다. 하이브리드 자동차에서 전기에너지를 저장하는 배터리는 가장 중요한 구성요소 중 하나이며, 하이브리드 자동차용 배터리(전기에너지를 저장하는 2차 전지)는 순간적으로 에너지를 방출하는 특성 즉 고출력 특성이 일차적으로 요구되며, 자동차 부품으로서의 신뢰성과 내구성이 확보되어야 한다. 따라서 본 논문에서는 하이브리드 자동차에 장착되는 2차 전지의 충 방전 상태를 안정적으로 모니터링 하는 시스템과 전지의 충 방전 성능을 극대화할 수 있고 충 방전 제어가 가능한 실시간 충 방전 모니터링 시스템을 제안하였다. 논문에서 새롭게 제안한 감지부와 제어부로 구성되는 충 방전 시스템은 하드웨어 및 소프트웨어 모듈과 실시간으로 셀 배터리의 충 방전 상태를 효율적으로 제어할 수 있으며 데이터베이스와 통신모듈을 기반으로 원격제어가 가능한 시스템이다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2002년도 학술대회논문집
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• pp.29-33
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• 2002

Period which does an electric condition of panel in reset in the driving method of PDP is reset period. This research experimentally analyzed the priming discharge characteristic of reset period. The amount of wall charge and the accumulation time accumulated by priming discharge are unrelated to width of priming pulse. And, self-erase discharge has the relation in the amount of wall charge by priming discharge. Then, it relates also to space charge generated by priming discharge. Moreover, space charge which helps self-erase discharge exists to about 22$mutextrm{s}$ after generating priming discharge. And, it is suitable within 12$mutextrm{s}$ of priming pulse width for efficient reset.

• Transactions on Electrical and Electronic Materials
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• 제11권1호
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• pp.42-47
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• 2010

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 $50^{\circ}C$ and $80^{\circ}C$ 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 $80^{\circ}C$, 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 $50^{\circ}C$ to $80^{\circ}C$. 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.