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1
Xia, Rong. "Characteristic Analysis and Measurement of Dielectric Loss in Non-Linear Insulating Materials." Advanced Materials Research 986-987 (July 2014): 1471–76. http://dx.doi.org/10.4028/www.scientific.net/amr.986-987.1471.
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Non-linear insulating material is widely used in the insulations of XLPE cable terminations and stator windings insulation of electric machines, and has obvious capability to improve the distribution of electric field. Actually, the dielectric loss factor of non-linear insulating materials is not equal to the tanδ describing linear insulating materials, and depends on applied voltage and their structures. This paper firstly discusses the difference between ac loss characteristic of non-linear dielectrics and linear dielectrics and presents a kind model of non-linear composite material. Based on the model, specific characterization and measurement methods and their numeric simulation analysis are given. Finally, a measuring system for non-linear insulating materials based on digital measuring technology is presented.
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Liu, Yong, and Xingwang Huang. "Effects of Flash Sintering Parameters on Performance of Ceramic Insulator." Energies 14, no. 4 (February 22, 2021): 1157. http://dx.doi.org/10.3390/en14041157.
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Ceramic outdoor insulators play an important role in electrical insulation and mechanical support because of good chemical and thermal stability, which have been widely used in power systems. However, the brittleness and surface discharge of ceramic material greatly limit the application of ceramic insulators. From the perspective of sintering technology, flash sintering technology is used to improve the performance of ceramic insulators. In this paper, the simulation model of producing the ceramic insulator by the flash sintering technology was set up. Material Studio was used to study the influence of electric field intensity and temperature on the alumina unit cell. COMSOL was used to study the influence of electric field intensity and current density on sintering speed, density and grain size. Obtained results showed that under high temperature and high voltage, the volume of the unit cell becomes smaller and the atoms are arranged more closely. The increase of current density can result in higher ceramic density and larger grain size. With the electric field intensity increasing, incubation time shows a decreasing tendency and energy consumption is reduced. Ceramic insulators with a higher uniform structure and a smaller grain size can show better dielectric performance and higher flashover voltage.
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Gavrilă, Doina Elena, and Horia Catalin Gavrilă. "Dielectric Properties of the Composite Insulator Mica Epoxy-Novolac." Advanced Materials Research 701 (May 2013): 47–52. http://dx.doi.org/10.4028/www.scientific.net/amr.701.47.
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As electric insulators of the copper conductors in the electric generators of alternative current or in electric motors of high tension, there are used with priority the composite crosslinked mica-epoxy. Pre-impregnated band with solvent was introduced, the impregnation being performed with phenolic-novolac resin. The studied material got superior dielectric properties at function temperatures corresponding to the insulation class F(155C). Its main components are: mica paper (53%), glass cloth (13%) and the basic epoxy phenolic-novolac resin. The complex permittivity and conductivity were determined with the Time Domain Spectrometer (TDS); the apparatus allows the determination of the electric values in the domain of frequencies: very large domain of frequencies. The temperature varied in the domain 23-190C with the help of an oven. The purpose of this article is to report the dielectric properties of mica-epoxy-novolac composite insulator, for which very few data have so far been published.
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Siagian, Marganda Harliman, T. Haryono, and Bambang Sugiyantoro. "Testing of Several Paper Types as Insulators for Electric Power Systems." IJITEE (International Journal of Information Technology and Electrical Engineering) 2, no. 3 (March 27, 2019): 91. http://dx.doi.org/10.22146/ijitee.43818.
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Abstract— This research was based on high voltage equipment failure due to an increase in temperature and humidity on insulating materials. This can cause the power system reliability to decrease. On the other hand, paper is frequently found and used in everyday life. Paper can be categorized as a solid insulator even tough its use in the electric power system can be considered as minimum. This paper aimed to determine electrical insulation characteristics of three types of paper on market and to determine the amount of failed voltage and leakage current of test materials included with other factors such as temperature rise effect as well as humidity conditions in sample testing. The employed test samples were photo paper, duplex paper, and samson craft paper with a length of 7 cm and width of 7 cm with different thickness for each paper type. Tests were carried out with two paper conditions, i.e. paper was soaked in Shell Diala B oil and was not soaked in Shell Diala B oil, so that the significance of the oil on the paper used as an ingredient in testing could be known. The test results showed that temperature and humidity affected dielectric strength magnitude and test sample leakage current value. In addition, it was also found that test sample result impregnated with Shell Diala B had a higher dielectric magnitude compared to the unimpregnated test sample. Test samples impregnated with Shell Diala B oil had a leakage current value which tended to be smaller than the unimpregnated test sample.
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Hadi, Nabipour Afrouzi, Zulkurnain Abdul-Malek, Saeed Vahabi Mashak, and A. R. Naderipour. "Three-Dimensional Potential and Electric Field Distributions in HV Cable Insulation Containing Multiple Cavities." Advanced Materials Research 845 (December 2013): 372–77. http://dx.doi.org/10.4028/www.scientific.net/amr.845.372.
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Cross-linked polyethylene is widely used as electrical insulation because of its excellent electrical properties such as low dielectric constant, low dielectric loss and also due to its excellent chemical resistance and mechanical flexibility. Nevertheless, the most important reason for failure of high voltage equipment is due to its insulation failure. The electrical properties of an insulator are affected by the presence of cavities within the insulating material, in particular with regard to the electric field and potential distributions. In this paper, the electric field and potential distributions in high voltage cables containing single and multiple cavities are studied. Three different insulating media, namely PE, XLPE, and PVC was modeled. COMSOL software which utilises the finite element method (FEM) was used to carry out the simulation. An 11kV underground cable was modeled in 3D for better observation and analyses of the generated voltage and field distributions. The results show that the electric field is affected by the presence of cavities in the insulation. Furthermore, the field strength and uniformity are also affected by whether cavities are radially or axially aligned, as well as the type of the insulating solid. The effect of insulator type due the presence of cavities was seen most prevalent in PVC followed by PE and then XLPE.
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Ali, Muhammad, and Muhammad Ahmad Choudhry. "Preparation and characterization of EPDM-silica nano/micro composites for high voltage insulation applications." Materials Science-Poland 33, no. 1 (March 1, 2015): 213–19. http://dx.doi.org/10.1515/msp-2015-0002.
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AbstractThe rising market for substitute materials in high voltage insulation components is stimulated largely by the need to reduce overall costs. In this respect, polymer insulators offer significant advantages over old traditional materials. In the present research, efforts have been made to quantify the effect of silica (having different particle size nano, micro and hybrid) loading on the mechanical and thermal behaviors of Ethylene-Propylene-Diene Monomer (EPDM) based high voltage electrical insulations. The fabricated composites were subjected to mechanical, thermal and electrical properties measurements. The results of dielectric strength, surface and volume resistivities showed that all composites had insulator properties, while their mechanical and thermal properties improved considerably. EPDM was compounded with different types of silica in a two roll mill using sulphur cure system. The outcome achieved from the comparative study revealed that the EPDM nanocomposites had enhanced mechanical, thermal and electrical properties even at 5 % loadings.
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Marín-Genescà, Marc, Jordi García-Amorós, Ramon Mujal-Rosas, Lluís Massagués Vidal, and Xavier Colom Fajula. "Application Properties Analysis as a Dielectric Capacitor of End-of-Life Tire-Reinforced HDPE." Polymers 12, no. 11 (November 12, 2020): 2675. http://dx.doi.org/10.3390/polym12112675.
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The purpose of the present research is to obtain waste of polymeric composite as an insulator capacitive application. Rubber materials, once they end their useful life, may be difficult to reuse or recycle. At present, research only uses one tire recycling method, which involves grinding and separating steel and fibers from vulcanized rubber, and then using the rubber particles for industrial capacitors. The methodology for this research is to compare the permittivity (ε′ and ε″) between high-density polyethylene (HDPE) and the polymer matrix compound, consisting of an HDPE polymeric matrix blended with end-of-life tire particles (ground tire rubber (GTR)), to analyze the feasibility of using such tires as electrically insulating materials (dielectrics). The incorporation of carbon black in the GTR compounds modifies conductivity; GTRs carry a significant amount of carbon black, and therefore some electrical properties may change significantly compared to highly insulating polymer substrates. The performed experimental study is based on a dynamic electric analysis (DEA) test developed in the frequency range of 10−2 Hz to 3 MHz and at different temperatures (from 35 to 70 °C) of different samples type: HDPE neat and HDPE compounds with 10%, 20% and 40% of GTR loads. A sample’s electrical behavior is checked for its dependence on frequency and temperature, focused on the permittivity property; this is a key property for capacitive insulators and is key for examining the possible applications in this field, for HDPE + GTR blends. Results for the permittivity behavior and the loss factor show different electrical behavior. For a neat HDPE sample, no dependence with frequency nor temperature is shown. However, with the addition of 10%, 20%, and 40% amount of GTR the HDPE compounds show different behaviors: for low frequencies, interfacial polarization relaxation is seen, due to the Maxwell–Wagner–Sillars (MWS) effect, performed in heterogeneous materials. In order to analyze thermal and morphological properties the differential scanning calorimetry (DSC) test and scanning electron microscopy (SEM) have been used. Results obtained show that adding waste tire particles in an HDPE matrix allows HDPE + 40% GTR blends to act as a dielectric in capacitors, increasing the capacitor dielectric efficiency in the low frequencies due to the MWS effect, which increases the dielectric constant.
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Jurado, Washington Colón Castillo, Antonio Vázquez Pérez Pérez, Alcira Magdalena Vélez Quiroz, and María Rodríguez Gámez. "Environmental Impact On Electrical Networks Near The Manabita Litoral." International Journal of Life Sciences (IJLS) 1, no. 2 (August 10, 2017): 18. http://dx.doi.org/10.21744/ijls.v1i2.30.
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The coastal area of Manabita and its surroundings is one of the most beautiful regions of the province, with an extraordinary tourist attraction that has not yet been exploited in its entire dimension. In it are located beaches like the Murciélago, Crucita, San Jacinto among others, that throughout the year are frequented by national and international tourists, who come looking for tranquility and recreation. This paper analyzes the influence of the industrial process of coffee, fish and oil production, which are important in the generation of large amounts of air pollutants, combined with the effects of the marine aerosol, Clay dust produced by the quarries located in the area, which under wind effects deposition of polluting layers on the elements that make up the electrical infrastructure, causing a high contamination of nets and insulation, causing that during the rainy season, The dielectrics behave like conductors, causing as a consequence that affects the service in the territory, mainly during the winter. A brief evaluation is made of the consequences of environmental pollution on the system of electric lines, networks and insulators and what it may represent for the project proposed by the state to introduce the efficient cooking program (PEC).
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Douar, Mohammed Adnane, Abderrahmane Beroual, and Xavier Souche. "Ignition and advancement of surface discharges at atmospheric air under positive lightning impulse voltage depending on perpendicular electric stress and solid dielectrics: modelling of the propagating phenomenology." European Physical Journal Applied Physics 82, no. 2 (May 2018): 20801. http://dx.doi.org/10.1051/epjap/2018180074.
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In many high voltage equipment, partial discharges are regarded as one of the most widespread pathology whose ignition conditions and effects are studied by scientists and manufacturers to avoid major failures. Actually, those electrical gaseous phenomena generally occur under several constraints such as the electrostatic field level, the nature of insulating surface being polluted or not, and switching or lightning transients. The present paper discusses physical mechanisms related to the creeping discharges propagation growing over insulators subjected to perpendicular electric field and positive lightning impulse voltage. More precisely, the developed discussion attempts to answer some observations especially noticed for main discharges feature namely (i) the discharges morphology, (ii) their velocity and (iii) the space charges effects on electric field computation. Several factors like (i) the influence of the type of a material’s interface, its electric conductivity, permittivity and discharges mobility, (ii) the relationship between the applied electrostatic field, the space charges, the velocity, the propelling pressure and discharges temperature are among numerous parameters that have been addressed in this study which discusses lightning impulse transients phenomena.
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Thabet, Ahmed, Youssef Mobarak, Nourhan Salem, and A. M. El-noby. "Performance comparison of selection nanoparticles for insulation of three core belted power cables." International Journal of Electrical and Computer Engineering (IJECE) 10, no. 3 (June 1, 2020): 2779. http://dx.doi.org/10.11591/ijece.v10i3.pp2779-2786.
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This paper presents an investigation on the enhancement of electrical insulations of power cables materials using a new multi-nanoparticles technique. It has been studied the effect of adding specified types and concentrations of nanoparticles to polymeric materials such as PVC for controlling on electric and dielectric performance. Prediction of effective dielectric constant has been done for the new nanocomposites based on Interphase Power Law (IPL) model. The multi-nanoparticles technique has been succeeded for enhancing electric and dielectric performance of power cables insulation compared with adding individual nanoparticles. Finally, it has been investigated on electric field distribution in the new proposed modern insulations for three-phase core belted power cables. This research has focused on studying development of PVC nanocomposite materials performance with electric field distribution superior to the unfilled matrix, and has stressed particularly the effect of filler volume fraction on the electric field distribution.
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Zhang, Zhijin, Tian Liang, Chen Li, Xingliang Jiang, Jian Wu, and Bin Wu. "Electrical Strength and Physicochemical Performances of HTV Silicone Rubber under Salt-Fog Environment with DC Energized." Polymers 12, no. 2 (February 4, 2020): 324. http://dx.doi.org/10.3390/polym12020324.
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In recent years, the performances of rubber composite insulators, which operate in the coastal foggy regions, have attracted researchers’ concern because of the observation of their degradation. In this paper, salt-fog experiments with DC test voltage of high-temperature vulcanized (HTV) silicone rubber (SR) have been conducted. The electrical strength and material performances of samples with salt-fog treatment were focused on. The DC flashover voltage, hydrophobicity, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and dielectric parameter were investigated. It was found that the samples’ performances deteriorated after salt-fog treatment. The DC flashover voltage of HTV SR decreased in the salt-fog environment. The hydrophobicity of the material deteriorated and the static contact angle (CA) became small. Under the action of electric and thermal stress, the surface of samples after salt-fog treatment became rough and porous. The absorption peak of the hydrophobic groups decreased, indicating that the molecular chain of SR material was broken, and the filler was consumed, bringing down the arc resistance of the sample. The absorption of moisture further led to insulation performance loss and then reduced the electrical strength of the material. Degradation of physicochemical properties will eventually lead to a decline in electrical strength.
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Azizi, D., and A. Gholami. "Optimum Scheme for Insulation System in HV Generator Based on Electromagnetic Analysis." Engineering, Technology & Applied Science Research 1, no. 3 (June 17, 2011): 49–53. http://dx.doi.org/10.48084/etasr.14.
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Electrical insulations are one of the basic parts of electrical machinery in any sizes and characteristics. Focusing on insulating, studies on the operation of industrial-electrical machinery came to the fact that the most important part of a machine is the Stator. This fact reveals the requirement for inspection of the electrical machine insulation along with the electromagnetic tensions. Therefore with respect to insulation system improvement of stator, the HV generator can be optimized. Dielectric parameters such as insulation thickness, spacing, material types, geometry of winding and slot are major design consideration. A very powerful method available to analyze electromagnetic performance is Finite Element Method (FEM) which is used in this paper. The analysis of various stator coil and slot configurations are used to design the better dielectric system to reduce electrical stresses in order to increase the power of generator in the same volume of core. These processes of optimization have been done according the proposed algorithm. In this algorithm the technical constraints have been considered. This paper describes the process used to perform classical design and improvement analysis of stator slot’s insulation with respect to objective function and constraints.
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Pleşa, Ilona, Petru Noţingher, Cristina Stancu, Frank Wiesbrock, and Sandra Schlögl. "Polyethylene Nanocomposites for Power Cable Insulations." Polymers 11, no. 1 (December 24, 2018): 24. http://dx.doi.org/10.3390/polym11010024.
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This review represents a comprehensive study of nanocomposites for power cables insulations based on thermoplastic polymers such as polyethylene congeners like LDPE, HDPE and XLPE, which is complemented by original results. Particular focus lies on the structure-property relationships of nanocomposites and the materials’ design with the corresponding electrical properties. The critical factors, which contribute to the degradation or improvement of the electrical performance of such cable insulations, are discussed in detail; in particular, properties such as electrical conductivity, relative permittivity, dielectric losses, partial discharges, space charge, electrical and water tree resistance behavior and electric breakdown of such nanocomposites based on thermoplastic polymers are described and referred to the composites’ structures. This review is motivated by the fact that the development of polymer nanocomposites for power cables insulation is based on understanding more closely the aging mechanisms and the behavior of nanocomposites under operating stresses.
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Jamail, N. A. M., M. A. M. Piah, N. A. Muhamad, Z. Salam, N. F. Kasri, R. A. Zainir, and Q. E. Kamarudin. "Effect of Nanofillers on the Polarization and Depolarization Current Characteristics of New LLDPE-NR Compound for High Voltage Application." Advances in Materials Science and Engineering 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/416420.
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Polymeric nanocomposites in which the nanosize fillers are evenly distributed in the polymer material attract attention as an insulating material due to their ability to enhance the materials performance properties of electrical and mechanical. For high voltage (HV) insulation application, one of the targets is to obtain new insulators with improved dielectric properties. This paper presents the outcome of an experimental study to determine the conductivity level of the linear low-density polyethylene- (LLDPE-)natural rubber (NR) compound, filled with different amount of SiO2and TiO2nanofiller by using the polarization and depolarization current (PDC) measurement technique. linear low-density polyethylene (LLDPE) and natural rubber (NR) with the ratio composition of 80 : 20 are selected as a base polymer. The experiment was conducted to find PDC pattern and conductivity variations of each of the LLDPE-NR/SiO2and LLDPE-NR/TiO2samples. The results show that the addition of SiO2filler exhibited less conductivity compared to TiO2filler with certain percentage. From the study, it can be concluded that LLDPE-NR/SiO2is a better insulator compared with LLDPE-NR/TiO2.
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Michelarakis, Michail, Phillip Widger, Abderrahmane Beroual, and Abderrahmane (Manu) Haddad. "Electrical Detection of Creeping Discharges over Insulator Surfaces in Atmospheric Gases under AC Voltage Application." Energies 12, no. 15 (August 1, 2019): 2970. http://dx.doi.org/10.3390/en12152970.
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Creeping discharges over insulator surfaces have been related to the presence of triple junctions in compressed gas insulated systems. The performance of dielectric materials frequently utilised in gaseous insulating high voltage applications, stressed under triple junction conditions, has been an interesting topic approached through many different physical perspectives. Presented research outcomes have contributed to the understanding of the mechanisms behind the related phenomena, macroscopically and microscopically. This paper deals with the electrical detection of creeping discharges over disc-shaped insulator samples of different dielectric materials (polytetrafluoroethylene (PTFE), epoxy resin and silicone rubber) using atmospheric gases (dry air, N2 and CO2) as insulation medium in a point-plane electrode arrangement and under AC voltage application. The entire approach implementation is described in detail, from the initial numerical field simulations of the electrode configuration to the sensing and recording devices specifications and applications. The obtained results demonstrate the dependence of the generated discharge activity on the geometrical and material properties of the dielectric and the solid/atmospheric gas interface. The current work will be further extended as part of a future extensive research programme.
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Seela-Or, Surapong, Kittipong Tonmitra, and Arkom Kaewrawang. "Solid Dielectric Barrier in Oil Insulator under Uniform and Non-Uniform Electric Fields." Advanced Materials Research 740 (August 2013): 540–44. http://dx.doi.org/10.4028/www.scientific.net/amr.740.540.
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This paper presents the dielectric barrier (PVC, PMMA, and glass) breakdown voltage test in transformer oil in uniform field, slight non-uniform field and highly non-uniform field generated by plate-plate, plate-point, and point-point electrodes, respectively. It was found that PVC can withstand the maximum breakdown voltage that is higher than PMMA and glass. The dielectric barrier with 1 mm thick placed next to the high voltage electrode and ground electrode can withstand the higher breakdown voltage than dielectric barrier with 2 mm thick placed next to the ground electrode and at the middle of electrodes. PVC for point-point, plate-point and plate-plate electrodes can withstand the maximum breakdown voltage of 216.5, 195.7 and 181 kV, respectively. The breakdown voltage of solid insulations is different because of the shape of electrode. These results lead to design the solid insulator in transformer oil under uniform and non-uniform electric fields.
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Li, Nan, Ji Huan Tian, Wei Deng, and Hui Gang Sun. "Application of Functionally Graded Materials for Solid Insulator: Fabrication, Optimization Design, and Surface Flashover of Prototype Samples." Applied Mechanics and Materials 291-294 (February 2013): 2308–12. http://dx.doi.org/10.4028/www.scientific.net/amm.291-294.2308.
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The applicability of functionally graded materials (FGM) for solid insulator of gas insulated switchgear (GIS) was investigated. First, a new fabrication method based on layer-by-layer casting technique was demonstrated to prepare FGM insulator possessing spatial distribution of dielectric constants. Then, electric field strength in the FGM spacer model was calculated and optimized by using finite element method (FEM). Three types of truncated cone spacers were fabricated according to the optimization results. Finally, surface flashover tests were performed under AC voltage and lightning impulse voltage applications. Results in both circumstances indicated an evident improvement of flashover voltage when FGM insulator was employed. As a result, we verified the fabrication technique and the applicability of FGM insulator for enhancement of insulation performance in GIS device.
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Hosoi, Takuji, Makoto Harada, Yusuke Kagei, Yuu Watanabe, Takayoshi Shimura, Shuhei Mitani, Yuki Nakano, Takashi Nakamura, and Heiji Watanabe. "AlON/SiO2 Stacked Gate Dielectrics for 4H-SiC MIS Devices." Materials Science Forum 615-617 (March 2009): 541–44. http://dx.doi.org/10.4028/www.scientific.net/msf.615-617.541.
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We propose the use of an aluminum oxynitride (AlON) gate insulator for 4H-SiC MIS devices. Since direct deposition of AlON on 4H-SiC substrate generates a large amount of interface charge due to an interfacial reaction, a thick AlON layer was deposited on underlying thin SiO2 thermally grown in N2O ambient. To reduce the negative fixed charge density in the aluminum oxide (Al2O3) film, we used reactive sputtering of Al in an N2/O2 gas mixture. The fabricated MIS capacitor with AlON/SiO2 stacked gate dielectric shows no flat band voltage shift and negligible capacitance-voltage hysteresis (30 mV), indicating the dielectric is almost free from both fixed charges and electrical defects. Owing to the high dielectric constant of AlON (k=6.9), as compared to single N2O-SiO2 gate insulator, significant gate leakage reduction was achieved by AlON/SiO2 stacked gate dielectrics even at high-temperature, especially in a high electric field condition (>5 MV/cm).
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YAGIL, YOAD, GUY DEUTSCHER, and DAVID J. BERGMAN. "THE ROLE OF MICROGEOMETRY IN THE ELECTRICAL BREAKDOWN OF METAL-INSULATOR MIXTURES." International Journal of Modern Physics B 07, no. 19 (August 30, 1993): 3353–74. http://dx.doi.org/10.1142/s0217979293003267.
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The breakdown phenomena of percolative metal-insulator composites and their extreme sensitivity to fine details of the microgeometry are discussed, for three different cases: the critical current of superconductor-insulator mixtures (or superconductor-normal metal); the dielectric breakdown of metal-insulator composites below the percolation threshold (insulating regime); and the electrical breakdown above the metal-insulator transition (metallic regime). Two experimental techniques for characterizing the microgeometry are described: (a) 1/f noise measurements, which provide the fourth moment of the current distribution; (b) the harmonic generation method, where the weakly nonlinear electrical response due to local Joule heating provides information on the fourth (and higher) moment of the current distribution.
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Mu, Qing Bo, Zhao Hua Zhang, Bu Chao Jia, and Jian Qiao Ma. "Distribution of Electric Field for EMU's Post Insulators Based on the Finite Element Method." Advanced Materials Research 1070-1072 (December 2014): 1652–55. http://dx.doi.org/10.4028/www.scientific.net/amr.1070-1072.1652.
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Compared with power system, post insulators used in High-speed Electric Multiple Unit (EMU) have unique features such as limited space, low number of sheds and complex pantograph, which produces high electric field at some part of post insulators. When the insulators electric field exceeds a numerical value, it will produce corona discharge and reduce the reliability of High-speed EMU. At the same time, a distinct discharge phenomenon has been observed on the surface of the small curvature radius for pantograph. For guiding optimization of electric field for post insulators and pantograph, a simplified model of post insulators as well as the pantograph is established to calculate the distribution of potential and electric field based on ANSYS. Because the applied voltage cycle is far less than the relaxation time of the dielectric, electrostatic field module can be used in the ANSYS Simulation. By simulating, the maximum electric field is occurred at the pantograph angle and some measures should be taken to reduce the electric field to assure the reliability of the EMU. The potential would decrease along the axis of the post insulator and the first umbrella bear the largest voltage drop.
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Zelmat, Samir, Marie Laure Locatelli, and Thierry Lebey. "Characterization of Polyimide Dielectric Layer for the Passivation of High Electric Field and High Temperature Silicon Carbide Power Devices." Materials Science Forum 483-485 (May 2005): 717–20. http://dx.doi.org/10.4028/www.scientific.net/msf.483-485.717.
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Silicon carbide (SiC) is a wide bandgap semiconductor suitable for high-voltage, highpower and high-temperature applications [1]. However, and among other issues, the production of advanced SiC power devices still remains limited due to some shortcomings of the dielectric properties of the passivation layer [2]. Due to their supposed high operating temperature and dielectric strength [3], spin coated polyimide materials appear as a possible candidates for SiC device passivation and insulation purposes. As a matter of fact, they are already used in current commercial SiC devices allowing a maximum junction temperature of 175 °C. The aim of this paper is to study the ability of polyimide (PI) coatings to be used for a Tjmax up to 300 °C. Therefore, the main electrical properties (dielectric permittivity, leakage current and breakdown field) at different temperatures of a high temperature commercially available polyimide material (from HD Microsystems) in both Metal-Insulator-Semiconductor (MIS) and Metal-Insulator-Metal (MIM) structures are presented and discussed.
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Kharal, Kamran, Ullah, Saleem, and Alvi. "Environment-Friendly and Efficient Gaseous Insulator as a Potential Alternative to SF6." Processes 7, no. 10 (October 14, 2019): 740. http://dx.doi.org/10.3390/pr7100740.
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Sulfur hexafluoride (SF6) is commonly used in electrical insulation networks due to its superior dielectric properties. However, it possesses a high Global Warming Potential (GWP) of 22,800 times compared to CO2 (at equal mass over a time span of 100 years) and a high atmospheric lifetime. This alarming metric prompted investigation for substitute gases with minor environmental influences. The overall objective of this research is to evaluate refrigerant R152a as a potential alternative for SF6 in electrical insulation systems. R152a gas has a significantly reduced value of GWP (140) and is a cheap insulation medium as compared to SF6. In this paper, dielectric breakdown testing of R152a and a mixture of CO2 with different concentrations have been tested. The dielectric strength of R152a/CO2 gas shows a saturated growth trend with increasing the gap difference, gas pressure and mixing ratio of R152a. Based on our experimental conditions, R152a/CO2 gas reveals good dielectric properties, and insulation performance can reach up to 96% of SF6. Finally, this work will bring a cost-effective and environment-friendly gaseous insulator for utility companies and power equipment manufacturers.
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KARHAN, MUSTAFA, MUSA FARUK CAKIR, and MUKDEN UGUR. "ANALYSIS OF ELECTRIC FIELD AND POTENTIAL DISTRIBUTION OF EXPERIMENTAL SETUP FOR INITIATING AND GROWING VENTED TYPE WATER TREES USING FINITE ELEMENT METHOD." Journal of Science and Arts 20, no. 3 (September 30, 2020): 755–66. http://dx.doi.org/10.46939/j.sci.arts-20.3-c02.
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Water treeing phenomenon has an important and effective role in the service life of polymeric insulators used in the transmission and distribution of electricity. Water trees can be described as permanently localized degradations or damages that can occur in the presence of electric field and humidity. XLPE is widely used as a polymeric insulator material in medium and high voltage cable applications. An experimental setup was prepared to initiate and grow water trees artificially in a laboratory environment and the tests were performed in accordance with the actual values. The electrical and dielectric values of the test material were used for a detailed analysis with high accuracy. The magnitude of the electric field, which was defined by varying the distance between the water needles formed in the XLPE material and the aluminium plate electrode, has been analyzed for various conditions. After laboratory experiments, electric field and potential distribution were simulated and analyzed by FEM (Finite Element Method) using FEMM (Finite Element Method Magnetics) software package. Experiments revealed clearly, that even small changes in the shape of water needle can dramatically affect the electric field and hence the lifetime of the insulator. By using FEMM, both of these parameters (electric field and potential distribution) can be calculated rapidly with high accuracy. HVDC power cables play a significant role in electric power transmission, hence by using the previously described experimental setup, electric field and potential distribution were simulated and analyzed under DC voltage.
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Akmal, Mohd Jamail Nor, Mohamed Piah Mohamed Afendi, Muhamad Nor Asiah, Zainir Rubiatul Addawiyah, and Kasri Nur Faizal. "Effects of SiO2 and TiO2 Nanofillers on Conductivity Level of LLDPE-NR Nanocomposite HV Insulator." Applied Mechanics and Materials 284-287 (January 2013): 305–9. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.305.
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Polymeric nanocomposites have gained importance in the material properties to provide enhanced performances such as electrical and mechanical properties. One of the targets in this field is to obtain new materials with improved dielectric properties for High Voltage (HV) insulation application. In general, the good insulator must have low conductivity level. This paper presents the outcome of an experimental study to find the conductivity level of LLDPE-Natural Rubber (NR) compound filled with different amount of nanoparticles of SiO2 and TiO2 by using Polarization and Depolarization Current (PDC) measurement technique. PDC measurement is an efficient and effective insulator diagnostic technique based on time domain measurement to monitor the dielectric behaviour. The experiment was conducted to find PDC pattern and conductivity variations of each new sample. The results show that the addition of SiO2 filler exhibited in less conductivity compared to TiO2 filler with certain percentage. LLDPE-NR/ SiO2 can be a good insulator compared with LLDPE-NR/ TiO2.
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Xayyavong, Mingkhouan, Kittipong Tonmitr, Norrawit Tonmitr, and Eiji Kaneko. "The Scrutiny of the Insulation Breakdown Strength for the Nanocomposite Oxide Doped Epoxy Resin Insulator with Different Electrodes by Using Positive Impulse Voltage." Key Engineering Materials 705 (August 2016): 63–67. http://dx.doi.org/10.4028/www.scientific.net/kem.705.63.
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This research presents the ratio of doping nanocomposite oxides in dielectric materials for increasing the efficiency strength and endurance voltage. Tests were conducted and analyzed the characteristics of epoxy nanozinc oxides. By using positive standard impulse voltage abilities of nanocomposite oxides were used as electrical insulators-epoxy resin doped with zinc oxides nanocomposite in ratios of 0, 5, 10, 15, and 20% by weight. And the design of electrodes embeds in the specimens with 4 types of electrode, as needle electrode, point electrode, spherical electrode and the partial spherical electrode. When adjusted the impulse voltage level of 75kV to the specimen immersed in transformer oil. The experiment aforementioned to investigate the ratios damages on insulator surfaces and the number of breakdowns. The microscopes with magnification levels of 20-800X were used to view the damages on insulator surfaces. Results, it was found that regarding specimens used for doping an epoxy resin with zinc oxides nanocomposite in a ratio of 5% had high withstand insulator with electrode types. The partial spherical electrode tested with positive impulse standard voltage has destructive distance lower damage than other electrode types.
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Bang, Seungmin, Ho-Seung Kim, Jae-Hong Koo, and Bang-Wook Lee. "Consideration of the Insulation Design Method on a ±200 kV Converter Valve Unit in an HVDC Converter Hall." Energies 14, no. 8 (April 19, 2021): 2296. http://dx.doi.org/10.3390/en14082296.
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A converter valve unit, which converts Alternating Current (AC) to Directing Current (DC) and DC to AC, is one of the key elements of high voltage direct current (HVDC) transmission. The insulation design of a converter valve unit should be considered for air clearance according to the DC superimposed overvoltage and the insulator that maintains the insulation performance and the corona shield to suppress DC corona discharge. There is no prescribed standard for the insulation design of a converter valve unit. Moreover, insulation performance under an applied DC voltage has not yet been thoroughly investigated. Therefore, it is necessary to study the insulation design method of the converter valve unit. In this paper, consideration of the insulation design method on a ±200 kV converter valve unit in an HVDC converter hall is performed. The finite element method (FEM) is used to simulate the 3D model. Additionally, the safety factor (SF) is applied in accordance with the dielectric test in IEC 62271-1. As a result, an insulation design process on the converter valve unit is proposed and the insulation design is carried through the design factors. It is confirmed that design factors on the air clearance, insulator and corona shield have a significant effect on a highly reliable insulation design.
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Wang, Quan, Huan Wang, and Qiong Xiang. "Research of Discharge Characteristics of CO2 Gas in Small Distance." Advanced Materials Research 860-863 (December 2013): 2194–98. http://dx.doi.org/10.4028/www.scientific.net/amr.860-863.2194.
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In order to find a new kind of insulates gas to substitute for SF6 gas, a discharge device has been development with shifter electrodes and adjusts distances automatic. Uniform electric field, non-uniform electric field had been achieved in this discharge device. The power-frequency voltage-withstand test of CO2 gas has been taken in these three kinds of electric field. In this test, data of breakdown voltage were obtained under different pressure and distances of electrodes with 99.99% purity of CO2. It can be seem from these data that the value of breakdown voltage is positive correlation to pressure and distances of electrodes. Whats more? For uniform electric field, the dielectric strength meet the requirement of power-frequency voltage-withstand of 110kV gas insulation device when the distance of test electrodes no less than 30mm. For non-uniform electric field, the dielectric strength of gas insulation of CO2 gas has little difference until the pressure increased to 0.5MPa. According to the data of power-frequency voltage-withstand test it can be conclude that the 0.5MPa is a key indicator to improve the insulating properties.
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Yang, Haitao, Zhensheng Wu, Weinan Dong, Junpeng Dang, and Hao Ren. "Analysis of the Influence of Silicone Rubber Aging on the Transmission Parameters of Terahertz Waves." Energies 14, no. 14 (July 14, 2021): 4238. http://dx.doi.org/10.3390/en14144238.
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In this study, a method for testing the aging of silicone rubber insulators using terahertz waves in the 0.17–0.22 THz frequency band is proposed, aiming at the problem of online non-destructive testing of the aging degree of composite insulators. The relationship between the aging degree of silicone rubber composite insulators and the relative dielectric constant was studied through first-principles calculations and molecular chain scission models. In addition, the electromagnetic model of the terahertz signal incident on the silicon rubber sheet was simulated and the relationship between the aging degree of the silicon rubber and the terahertz input return loss was obtained. Eleven insulator samples with different degrees of aging were selected. In these samples, the degree of aging was calibrated according to the degree of surface deterioration and the average partial discharge voltage. The terahertz return loss measurement experiment was performed after that. Finally, the results of experiment and calculation simulation were compared and the reliability of the relationship between the aging degree of the silicone rubber insulator and the terahertz input return loss was verified.
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Nesenyuk, Tatyana Anatolyevna, and Ekaterina Evgenyevna Poluyanova. "RFID-indicators for polymer stick insulators." Transport of the Urals, no. 3 (2020): 82–88. http://dx.doi.org/10.20291/1815-9400-2020-3-82-88.
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The paper is devoted to the use of RFID-technology in electrical power engineering, in particular, for controlling the condition of high-voltage equipment of feeding transmission lines. It also describes studies on development of RFID-tag designed to indicate dielectric condition of line polymer insulator. The authors present results of tests of pilot samples of LKi-70/110-4-GP-UKhL1 polymer stick insulators with built-in RFID-indicators. The tests have been executed in accordance with the GOST R 55189-2012 requirements. As a result, the authors have made a conclusion on the possibility of using RFID-technologies for technical control of insulators on overhead transmission lines, high-voltage equipment of traction and transformer substations.
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Vu, Thi Thu Nga, Gilbert Teyssedre, and Séverine Le Roy. "Electric Field Distribution in HVDC Cable Joint in Non-Stationary Conditions." Energies 14, no. 17 (August 30, 2021): 5401. http://dx.doi.org/10.3390/en14175401.
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Accessories such as joints and terminations represent weak points in HVDC cable systems. The DC field distribution is intimately dependent on the thermal conditions of the accessory and on material properties. Moreover, there is no available method to probe charge distribution in these conditions. In this work, the field distribution in non-stationary conditions, both thermally and electrically, is computed considering crosslinked polyethylene (XLPE) as cable insulation and different insulating materials (silicone, rubber, XLPE) for a 200 kV joint assembled in a same geometry. In the conditions used, i.e., temperatures up to 70 °C, and with the material properties considered, the dielectric time constant appears of the same order or longer than the thermal one and is of several hours. This indicates that both physical phenomena need to be considered for modelling the electric field distribution. Both the radial and the tangential field distributions are analysed, and focus is given on the field distribution under the stress cone on the ground side and near the central deflector on the high voltage side of the joint. We show that the position of the maximum field varies in time in a way that is not easy to anticipate. Under the cone, the smallest tangential field is obtained with the joint insulating material having the highest electrical conductivity. This results from a shift of the field towards the cable insulation in which the geometrical features produce a weaker axial component of the field. At the level of the central deflector, it is clear that the tangential field is higher when the mismatch between the conductivity of the two insulations is larger. In addition, the field grows as a function of time under stress. This work shows the need of precise data on materials conductivity and the need of probing field distribution in 3D.
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ANDREI, Laura, and Florin CIUPRINA. "ANALIZA CONDUCTIVITĂȚII ELECTRICE A NANOCOMPOZITELOR PVC-TiO2 PRIN SPECTROSCOPIE DIELECTRICĂ." "ACTUALITĂŢI ŞI PERSPECTIVE ÎN DOMENIUL MAŞINILOR ELECTRICE (ELECTRIC MACHINES, MATERIALS AND DRIVES - PRESENT AND TRENDS)" 2020, no. 1 (February 10, 2021): 1–7. http://dx.doi.org/10.36801/apme.2020.1.9.
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Electrical conductivity of polyvinyl chloride (PVC) and of PVC-TiO2 nanocomposites with TiO2 nanoparticle concentration of 5% was analyzed by dielectric spectroscopy in the frequency range 10^-2 – 10^6 Hz, and for three different temperatures: 310, 320 and 340 K. Frequency variation of the imaginary part of the complex permittivity was analyzed with Havriliak-Negami (HN) model. Temperature influence on this variation was used to determine the activation energy of electric conduction in the studied materials. Frequency variation of the real part of the complex permittivity was analyzed, as well, and the temperature influence on DC conductivity (σDC) and AC conductivity (σAC) was discussed in the paper. The obtained results emphasize an important temperature influence on the dielectric response and, consequently, on the electrical conductivity, especially at low frequencies up to 10^2 Hz, for both PVC and PVC-TiO2 nanocomposites. Thus, at low frequencies in the range 10^-2 – 10^2 Hz, high frequency variations of the imaginary part of the complex permittivity can be noticed, which indicate important charge movements through the polymeric material under electric field. The increase of the temperature leads to an increase of the DC conductivity values, and to an increase of the frequency threshold up to which a frequency independent electrical conduction can be observed. The study presented in this paper shows that the dielectric spectroscopy is a performant tool that allows, besides the highlighting of dielectric relaxations corresponding to the different polarization types from polymeric materials, also to characterize these materials from the point of view of electric conduction. Thus, by dielectric spectroscopy, the electrical insulating materials from the insulations of power cables and electrical machines can be analyzed in a large range of frequencies and temperatures, which allows the understanding of the behavior of these materials in different operating conditions.
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Yoneda, Kenji, Yoshihiro Todokoro, and Morio Inoue. "Thin silicon dioxide and nitrided oxide using rapid thermal processing for trench capacitors." Journal of Materials Research 6, no. 11 (November 1991): 2362–70. http://dx.doi.org/10.1557/jmr.1991.2362.
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Electrical characteristics of trench capacitors using RTO (Rapid Thermal Oxidation) oxides, nitroxides, and reoxidized nitroxides as the gate insulators are discussed. High temperature RTO is effective in preventing oxide thinning at the trench corner, and so the dielectric strength of trench capacitors is improved drastically. The mean time to failure (MTTF) of trench capacitors using RTO is more than ten times longer than that of trench capacitors using conventional furnaces. Using reoxidized nitroxides as the gate insulator, superior charge to breakdown (QBD) is obtained. RTP (Rapid Thermal Processing) is superior to the process using the conventional furnace for the gate insulators of trench capacitors. Improvements in temperature uniformity, repeatability, and lessening of slip line formation are essential for RTP equipment to be practical.
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Wahab, M. H. A., N. A. M. Jamail, E. Sulaiman, Q. E. Kamarudin, N. A. Othman, and S. M. N. S. Othman. "Space Charge and Electric Field Analysis on Contaminated XLPE Insulator." Indonesian Journal of Electrical Engineering and Computer Science 12, no. 1 (October 1, 2018): 370. http://dx.doi.org/10.11591/ijeecs.v12.i1.pp370-377.
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<p>Nowadays, XLPE cable has been widely used because it has better resistance than other cables. XLPE insulation has unique features including a high dielectric strength and high insulation resistance. A lot of researches based on hardware and software have been conducted to prove the effectiveness of XLPE cable such as AC and DC applications and Space Charge Distribution measurement under HVDC at High Temperature. This research focused on analysis of space charge and electric field on XLPE cable with effect of non-uniform contamination layer by using Quickfield Software. Non-uniform contaminations have been applied along XLPE cable using Arsenic Tribromide (AsBr3), Boron Bromide (BBr3), Ethylene Dichloride (CH2C1), Formic Acid (CH1O2), Formamide (CH3NO) and Alcohol element. Presence of these contamination elements represent of underground contamination. The size and layer of the contamination were non-uniform type. From the results, it is shown that lower dielectric constant of contamination will affect more on charge of XLPE insulation. As a conclusion, it can be seen lower dielectric constant value of contamination element greatly affecting the performance of XLPE insulation. Furthermore, size of contamination also influences the content of charge in contamination where the bigger the contamination size, the more charge contained in the contamination.</p>
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Han, Ke, Xubing Guo, Stewart Smith, Zhongliang Deng, and Wuyu Li. "Novel High-Capacitance-Ratio MEMS Switch: Design, Analysis and Performance Verification." Micromachines 9, no. 8 (August 6, 2018): 390. http://dx.doi.org/10.3390/mi9080390.
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This paper proposes a novel high-capacitance-ratio radio frequency micro-electromechanical systems (RF MEMS) switch. The proposed RF MEMS mainly consists of serpentine flexure MEMS metallic beam, comprised of coplanar waveguide (CPW) transmission line, dielectric and metal-insulator-metal (MIM) floating metallic membrane. Comparing the proposed high-capacitance-ratio MEMS switch with the ones in available literature, an acceptable insertion loss insulation, acceptable response time and high capacitance ratio (383.8) are achieved.
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Kumta, A., E. Rusli, and Chin Che Tin. "Design and Analysis of a Dual-Step Field-Plate Terminated 4H-SiC Schottky Diode Using SiO2/High-K Dielectric Stack." Materials Science Forum 527-529 (October 2006): 1171–74. http://dx.doi.org/10.4028/www.scientific.net/msf.527-529.1171.
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Silicon carbide (SiC) field plate terminated Schottky diodes using silicon dioxide (Si02) dielectric experience high electric field in the insulator and premature dielectric breakdown, attributed to the lower dielectric constant of the oxide. This problem can be addressed by using high-k dielectrics such as silicon nitride (Si3N4) that will reduce the field, increase the breakdown voltage and consequently improve the lifetime of the devices. While the advantages of single step field-plate terminated diodes are well-known, the breakdown voltage can be improved even further using a dual-step field-plate termination. Our 2D-numerical simulations using MEDICI have shown an improvement in breakdown voltages in excess of 25% compared to the traditional single-step field-plate terminated diodes.
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SIMA, WENXIA, JIAN SHI, and QING YANG. "SURFACE DISCHARGE SIMULATION IN SF6 AND N2 MIXTURES WITH A PLASMACHEMICAL MODEL." Surface Review and Letters 21, no. 01 (February 2014): 1450010. http://dx.doi.org/10.1142/s0218625x14500103.
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SF 6– N 2 mixtures are becoming the best alternative for SF 6 in electrical systems. Plasmachemical modeling and the results of a positive surface streamer are reported in this paper. The model exhibits excellent streamer transition from the gas gap to the insulator surface. The surface charge accumulations on the dielectric insulators are compared and discussed. Results showed that the density of negative ions is much larger than that of electrons in the surface streamer channel. The dominant [Formula: see text] and less pronounced [Formula: see text] constitute the main negative ions in the electronegative surface streamer because of the strong electron attachments to SF 6 molecules.
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Yokota, Takeshi, Takaaki Kuribayashi, Takeshi Shundo, Keita Hattori, Yasutoshi Sakakibara, and Manabu Gomi. "Magnetic and Dielectric Properties of a Metal/ Cr2O3/Cr2O3-x/Cr2O3/Semiconductor Capacitor Using Magneto-Electric Materials." Key Engineering Materials 350 (October 2007): 221–24. http://dx.doi.org/10.4028/www.scientific.net/kem.350.221.
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We investigated the magnetic and dielectric properties of a metal (Pt)/insulator (Cr2O3)/semiconductor (Si) (MIS) capacitor composed of magneto-electric (ME) materials. The capacitor has anti-ferromagnetic properties and a very small electrically induced magnetic moment. It also shows capacitance-voltage (C-V) properties typical of a Si-MIS capacitor without any hysteresis. By inserting a thin Cr2O3-x layer, the C-V curve has a hysteresis window with a clockwise trace, which indicates that electrons have been injected into the Cr2O3-x layer. These results indicate that this MIS capacitor contains a floating gate and an ME insulating layer in a single system.
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Berrag, A., S. Belkhiat, and L. Madani. "Investigation of dielectric behavior of the PVC/BaTiO3 composite in low-frequencies." International Journal of Modern Physics B 32, no. 09 (April 5, 2018): 1850110. http://dx.doi.org/10.1142/s0217979218501102.
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Polyvinyl chloride (PVC) is widely used as insulator in electrical engineering especially as cable insulation sheaths. In order to improve the dielectric properties, polymers are mixed with ceramics. In this paper, PVC composites with different weight percentages 2 wt.%, 5 wt.%, 8 wt.% and 10 wt.% were prepared and investigated. Loss index ([Formula: see text]) and dielectric constant ([Formula: see text]) have been measured using an impedance analyzer RLC. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) equipped with energy dispersive X-ray (EDX) have been used as characterization techniques. The incorporation of BaTiO3 does not modify the crystallinity and the morphology of the PVC but reduces the space charges, therefore the dielectric losses. The frequency response analysis has been followed in the frequency ranges (20–140 Hz and 115–1 MHz). Relaxation frequencies have been evaluated in each frequency range. Experimental measurements have been validated using Cole–Cole’s model. Experimental results show well that BaTiO3 as a filler improves the dielectric properties of PVC.
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Golenischev-Kutuzov, A. V., D. A. Ivanov, A. A. Potapov, and V. I. Krotov. "Using contactless methods of diagnostics of high electric fields." Power engineering: research, equipment, technology 21, no. 4 (December 9, 2019): 123–33. http://dx.doi.org/10.30724/1998-9903-2019-21-4-123-133.
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In the electric power industry of Russia and abroad, special attention is paid to the problem of an increase in the number of accidents caused by damage to high-voltage insulators in high-voltage equipment. An analysis of emergencies at substations and open switchgears [1- 2, 4] was carried out, which showed that in most cases the causes of damage to high-voltage insulators are natural aging in an applied electric field, overvoltage, and the presence of initial defects in the manufacture of high-voltage insulators. Based on this fact, we developed various methods of non-contact diagnostics of high-voltage insulators in order to identify defects at an early stage of their development. Particular attention was paid to the method of partial discharges because the characteristics of partial discharges provide information on the parameters of defects. The article describes a set of non-contact methods for remote diagnostics of high-voltage insulators; a two-channel method for remote diagnostics of the operating state of high-voltage insulators, based on the registration of partial discharges by electromagnetic and acoustic sensors; a device that allows visual inspection and the search for faulty high-voltage equipment; remote non-contact method for recording electric fields of high tension of industrial frequency, as well as their spatial orientation based on the electro-optical effect. We developed a mock-up of a portable diagnostic device for implementing research methods for high-voltage dielectric elements to diagnose their technical condition using the described complex of non-contact methods. The measuring device as part of a portable diagnostic device consists of a set of sensors for collecting diagnostic information detected by electromagnetic, acoustic and electro-optical sensors and a voltage phase signal applied to the studied highvoltage insulator. The simultaneous use of several sensors at once made it possible to increase the accuracy of localization of partial discharges in high-voltage insulators. Visualization of diagnostic results is possible at the control room in the form of amplitude-phase, frequencyphase and amplitude-frequency diagrams of the distribution of characteristics of partial discharges and on a portable device in the form of radiation intensity from the selected sensor. A portable diagnostic device made it possible in laboratory conditions to study electrophysical processes in various dielectric materials and products under the influence of strong alternating electric fields. A study was made of the features of defects on the rod and the terminal-terminal contact, a diagram of the electrophysical processes accompanying the emission of partial discharges was constructed, and the causes of their occurrence were established.
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Бондаренко, Г. Г., М. С. Дубинина, and В. И. Кристя. "Влияние усиленной электрическим полем термической электронной эмиссии на температуру катода с тонкой диэлектрической пленкой в дуговом газовом разряде." Журнал технической физики 90, no. 5 (2020): 862. http://dx.doi.org/10.21883/jtf.2020.05.49191.403-18.
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A model of thermal electron emission enhanced by the electric field (thermo-field emission) from the metal cathode substrate into a thin insulating film formed on its surface is developed. A system of equations for the cathode surface temperature in the arc discharge and the electric field strength in the film, providing the required discharge current density, is formulated. It is shown that existence of the dielectric film can result in a considerable reduction of the cathode temperature in the discharge due to lower potential barrier height at the metal-insulator boundary than at the metal-discharge boundary in case of the metal cathode without the film. It is found that due to an enhancement of thermal emission of electrons into the film by the electric field generated in it, an additional decrease of the cathode temperature by about 100 K takes place.
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Liu, Chang, Yiwen Xu, Daoguang Bi, Bing Luo, Fuzeng Zhang, Tingting Wang, Yingbang Yao, Shengguo Lu, and Wenrong Xu. "The Effects of Aluminum-Nitride Nano-Fillers on the Mechanical, Electrical, and Thermal Properties of High Temperature Vulcanized Silicon Rubber for High-Voltage Outdoor Insulator Applications." Materials 12, no. 21 (October 30, 2019): 3562. http://dx.doi.org/10.3390/ma12213562.
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AlN nanoparticles were added into commercial high-temperature-vulcanized silicon rubber composites, which were designed for high-voltage outdoor insulator applications. The composites were systematically studied with respect to their mechanical, electrical, and thermal properties. The thermal conductivity was found to increase greatly (>100%) even at low fractions of the AlN fillers. The electrical breakdown strength of the composites was not considerably affected by the AlN filler, while the dielectric constants and dielectric loss were found to be increased with AlN filler ratios. At higher doping levels above 5 wt% (~2.5 vol%), electrical tracking performance was improved. The AlN filler increased the tensile strength as well as the hardness of the composites, and decreased their flexibility. The hydrophobic properties of the composites were also studied through the measurements of temperature-dependent contact angle. It was shown that at a doping level of 1 wt%, a maximum contact angle was observed around 108°. Theoretical models were used to explain and understand the measurement results. Our results show that the AlN nanofillers are helpful in improving the overall performances of silicon rubber composite insulators.
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Youngs, I. J. "Dielectric measurements and analysis for the design of conductor/insulator artificial dielectrics." IEE Proceedings - Science, Measurement and Technology 147, no. 4 (July 1, 2000): 202–8. http://dx.doi.org/10.1049/ip-smt:20000462.
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Cheng, Lin, Lee, Chen, and Fang. "Electrical Characteristics and Reliability of Nitrogen-Stuffed Porous Low-k SiOCH/Mn2O3-xN/Cu Integration." Molecules 24, no. 21 (October 28, 2019): 3882. http://dx.doi.org/10.3390/molecules24213882.
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In our previous study, a novel barrier processing on a porous low-dielectric constant (low-k) film was developed: an ultrathin Mn oxide on a nitrogen-stuffed porous carbon-doped organosilica film (p-SiOCH(N)) as a barrier of the Cu film was fabricated. To form a better barrier Mn2O3-xN film, additional annealing at 450 °C was implemented. In this study, the electrical characteristics and reliability of this integrated Cu/Mn2O3-xN/p-SiOCH(N)/Si structure were investigated. The proposed Cu/Mn2O3-xN/p-SiOCH(N)/Si capacitors exhibited poor dielectric breakdown characteristics in the as-fabricated stage, although, less degradation was found after thermal stress. Moreover, its time-dependence-dielectric-breakdown electric-field acceleration factor slightly increased after thermal stress, leading to a larger dielectric lifetime in a low electric-field as compared to other metal-insulator-silicon (MIS) capacitors. Furthermore, its Cu barrier ability under electrical or thermal stress was improved. As a consequence, the proposed Cu/Mn2O3-xN/p-SiCOH(N) scheme is promising integrity for back-end-of-line interconnects.
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Münster, Tobias, Peter Werle, Kai Hämel, and Jörg Preusel. "Thermally Accelerated Aging of Insulation Paper for Transformers with Different Insulating Liquids." Energies 14, no. 11 (May 24, 2021): 3036. http://dx.doi.org/10.3390/en14113036.
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The article presents issues related to the aging behavior of oil-paper insulations in transformers using different oil- and ester-based insulating fluids. Despite numerous conducted studies on the subject of oil-paper aging, the use of new insulating fluids is creating open questions. In addition, new liquids such as synthetic and natural esters, as well as oil of the newest generation, are being used. Furthermore, there is still little research on the formation of aging markers with this form of the dielectric. For this reason, in this contribution, oil-paper insulations with mineral oil-based insulating fluids, natural and synthetic esters, as well as oil from natural gas, are aged thermally accelerated at 130 °C over a duration of 15 weeks, by considering two cases of free-breathing and hermetically sealed transformers. Therefore, various aging markers are investigated to allow a condition assessment. The results show that differences exist between the fluids and design of the transformer, as in the aging rate of the paper and the formation of aging markers in the insulating liquid such as acids. These findings can be used to improve asset management strategies by a more precise determination of the aging state depending on the transformer type as well as the type of insulating fluid.
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Laraba, M. "Characterization of Algerian kaolins for utilization as a raw material in electrical insulators." Cerâmica 65, no. 374 (June 2019): 267–73. http://dx.doi.org/10.1590/0366-69132019653742556.
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Abstract The aim of this investigation was to characterize three samples of kaolin (DD1, DD2 and DD3) collected from Djebel Debbagh deposit (East of Algeria) to be used in electrical porcelain insulators. Grain-size analysis, X-ray fluorescence, X-ray diffraction, scanning electron microscopy and thermal analysis (TG-DTA) were performed. Each sample was mixed with feldspar and silica to obtain three porcelain formulations. The obtained results indicated that the three kaolins were composed by kaolinite and halloysite with variable contents of MnO and Fe2O3 as associated impurities. It was found that the DD1 was the appropriate kaolin as raw material for making the high-voltage electrical insulator which had the highest electrical and mechanical properties (dielectric strength, bending strength and bulk density), while DD2 and DD3 were less suitable due to their lower properties caused by the presence of impurities which must be removed.
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Маймистов, А. И., and Е. И. Ляшко. "Спиновый угловой момент нелинейной поверхностной волны на границе раздела обычного и топологического изоляторов." Журнал технической физики 126, no. 5 (2019): 578. http://dx.doi.org/10.21883/os.2019.05.47656.356-18.
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AbstractThe surface waves that propagate along the interface of a dielectric with nonlinear susceptibility of the third order and topological insulator have been considered. The optical nonlinearity of the dielectric ensures the existence of a surface wave. The density of the spin angular momentum of a surface wave has been determined for dielectrics with positive or negative linear permittivity. It has been shown that the spin angular momentum vector has a projection on the normal to the interface, which is different from the usual surface polaritons or plasmon polaritons. The discrete nature of the topological number manifests itself in the discreteness of the values of the normal and tangential components of the spin angular momentum density. The increase in the intensity of the electric field of the wave at the interface of the media changes the value of the spin angular momentum and can lead to its disappearance.
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Nechmi, Houssem Eddine, Mohammed El Amine Slama, Abderrahmane (Manu) Haddad, and Gordon Wilson. "AC Volume Breakdown and Surface Flashover of a 4% NovecTM 4710/96% CO2 Gas Mixture Compared to CO2 in Highly Nonhomogeneous Fields." Energies 13, no. 7 (April 3, 2020): 1710. http://dx.doi.org/10.3390/en13071710.
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AC pre-discharge currents, breakdown, and flashover voltage measurements are reported in a 10 mm needle-plane arrangement in a 4% NovecTM 4710/96% CO2 gas mixture and compared with CO2 for pressures up to 8.8 bar abs. Flashover measurements were performed on different solid dielectrics (Al2O3_filled epoxy resins, PTFE (Polytetrafluoroethylene) and PE (polyethylene)) for different roughness surface finishes. The effect of fixed conducting needles at various positions on electrical strength is reported. A strong nonlinear behaviour as function of gas pressure was observed for all the studied parameters (gas, needle position, solid insulator, insulator roughness). The non-linear behaviour is attributed to the inception and quenching of glow corona, in the interval between inception and breakdown or flashover voltages. It is found that a 4% concentration of NovecTM 4710 in CO2 has a breakdown/flashover voltage ≈ 1.14 higher than CO2. The glow corona-induced stabilization effect is seen for pressures between 2 and 5 bar abs for all the studied parameters. The peak flashover voltage and its associated pressure of the different insulators are strongly dependent on surface roughness. At 8.8 bar abs, the flashover voltage level obtained with various materials was ordered as follows: PTFE > PE-UHMW > Epoxy > HDPE(High-density polyethylene).
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FAN, JIE, XIAORONG LUO, BO ZHANG, and ZHAOJI LI. "NOVEL HIGH VOLTAGE SILICON-ON-INSULATOR DEVICE WITH COMPOSITE DIELECTRIC BURIED LAYER." Journal of Circuits, Systems and Computers 22, no. 10 (December 2013): 1340029. http://dx.doi.org/10.1142/s021812661340029x.
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A novel silicon-on-insulator (SOI) high voltage device with a composite dielectric buried layer (CD SOI) is proposed in this paper. In the proposed structure, the composite dielectric buried layer consists of Si 3 N 4 dielectric and low-k (relative permittivity) dielectric. The electric field strength in the buried layer is enhanced by the low-k dielectric. The Si 3 N 4 dielectric in the buried layer not only modulates the electric field distribution in the drift region, but also provides a heat conduction path for the SOI layer and alleviates the self-heating effect (SHE). The breakdown voltage (BV) = 362 V for CD SOI is obtained by simulation on a 1 μm SOI layer over 2 μm buried layer, which is enhanced by 26% compared with that of conventional SOI.
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Chiu, C. J., Z. W. Pei, S. P. Chang, and S. J. Chang. "Influence of Weight Ratio of Poly(4-vinylphenol) Insulator on Electronic Properties of InGaZnO Thin-Film Transistor." Journal of Nanomaterials 2012 (2012): 1–7. http://dx.doi.org/10.1155/2012/698123.
Full textAbstract:
Spin-coated organic PVP layers were used as dielectric layers in a-IGZO TFTs. Weight ratios of 20 : 1, 10 : 1, and 5 : 1 for PVP and PMF, a cross-linking agent, were used. The a-IGZO TFTs with the PVP : PMF ratio of 20 : 1 showed a large hysteresis in theI-Vcurve andC-Vcurve, the hysteresis increases with the increase of hydroxyl groups and also deteriorated the gate leakage current. In contrast, the devices with the PVP : PMF ratio of 5 : 1 dielectric displayed only small hysteresis. According to our experimental results, preventing the possible diffusion of hydroxyl-contained species in polymeric dielectrics is a very important factor in improving the electrical properties of high-performance a-IGZO TFT devices.
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Giannakopoulos, A. E. "Strength Analysis of Spherical Indentation of Piezoelectric Materials." Journal of Applied Mechanics 67, no. 2 (October 13, 1999): 409–16. http://dx.doi.org/10.1115/1.1304913.
Full textAbstract:
The present paper deals with theoretical and computational analysis of quasi-static, normal indentation of a transversely isotropic, linear elastic, piezoelectric half-space by a rigid spherical indenter. The contact is axisymmetric, nonconforming, monotonically advancing with load, frictionless and adhesionless. The indenter was modeled either as perfect conductor or as perfect insulator. The mechanical and electrical fields below the surface were examined. The issues of mechanical and dielectric strength due to indentation were examined using Weibull statistics of surface imperfections. The particular cases of PZT-4, PZT-5A, BaTiO3, and Ba0.917Ca0.083TiO3 indented by rigid punches having either zero electrical potential or zero electric charge were solved with finite element analysis. [S0021-8936(00)02502-2]