Aim To analyze the transient speciality of nonlinear, anisotropic, AC+DC coupling electric field, and to compare the withstand voltage strength of different insulation structures. Methods The transient process o...Aim To analyze the transient speciality of nonlinear, anisotropic, AC+DC coupling electric field, and to compare the withstand voltage strength of different insulation structures. Methods The transient process of polarity reversal is analyzed, considering the anisotropic property of oil immersed press board, a new finite element model based on Galerkin method is presented and verified. The model developed is applied to calculate the electric field distribution in four typical winding end structures of the converter transformer. Results\ The whole ring structure possesses the best insulation characteristics. Conclusion\ By introducing reasonable insulation components, insulation strength with the same surrounding sizes can be improved more than 30%.展开更多
Based on Fabry model and finite-different time-domain(FDTD) method, the plasmonic structure composed of a metal-insulator-metal(MIM) bus waveguide and a side-coupled resonator was investigated. It is found that the tr...Based on Fabry model and finite-different time-domain(FDTD) method, the plasmonic structure composed of a metal-insulator-metal(MIM) bus waveguide and a side-coupled resonator was investigated. It is found that the transmission features can be regulated by the cavity width and coupling distance. Electromagnetically induced transparency(EIT)-like transmission can be excited by adding an identical resonator on the pre-existing structure. Combining the foregoing theoretical analysis with coupled mode theory(CMT), the formation process of the EIT-like transmission was detailedly analyzed. EIT-like transmission can also be excited in plasmonic structure with two detuned resonators. By altering the structure parameters, the transparency window can be purposefully modulated. With the merits of compact structure and simplicity in fabrication, the proposed structures may have a broad prospect of applications in highly integrated optical circuits.展开更多
In this work we show the influence of the edge-effect on the electric field distribution and, hence, on the inner and outer capacitance in an inclined-plate capacitor system surrounded by an insulating medium taking i...In this work we show the influence of the edge-effect on the electric field distribution and, hence, on the inner and outer capacitance in an inclined-plate capacitor system surrounded by an insulating medium taking into account the thickness of the conducting plates for a complete set of dimensions and insulating characteristics. Where available, we compare our results with previously published works. Finally, using statistical tools, we obtain approximate expression for computing the relationship between capacitance and insulation material characteristics, insulation gap, plate dimensions and angle.展开更多
The oil-pressboard insulation is a typical composite insulation system widely used in the design and manufactory of large power apparatus. The implement of oil-pressboard insulation may lead to surface electrification...The oil-pressboard insulation is a typical composite insulation system widely used in the design and manufactory of large power apparatus. The implement of oil-pressboard insulation may lead to surface electrification and discharge at the interface under certain condition. It is of significant importance to take an insight into the phenomenon occurring at the interface. Through experiment, the pressboard is found as a porous material. The interface changes abruptly from bulk pressboard to the bulk oil as a result of the porous structure. A new model is proposed which divides the interface into bulk oil region, transition region, and bulk pressboard region. The width of the transition region is decided according to the microtome figure. The effective permittivity of the transition region is calculated using a new model based on fractal theory. The model is validated and compared with previous calculation model. The effect of the existence of transition region on the electric field distribution is discussed.展开更多
The purpose of this paper is to show the influence of the edge-effect on the electric field distribution, and hence on the inner capacitance and outer capacitance of a cylindrical capacitor surrounded by an insulating...The purpose of this paper is to show the influence of the edge-effect on the electric field distribution, and hence on the inner capacitance and outer capacitance of a cylindrical capacitor surrounded by an insulating medium. To generalize the results, a two-dimensional axisymmetric finite element model of a cylindrical capacitor has been generated and the problem has been resolved taking into account the distance between the conductors for a complete set of dimensions. The available obtained results have been compared with previous published works. Finally, using statistical tools, the mathematical expression for computing the relationship between capacitance and insulation gap and cylindrical plates dimensions has been obtained.展开更多
文摘Aim To analyze the transient speciality of nonlinear, anisotropic, AC+DC coupling electric field, and to compare the withstand voltage strength of different insulation structures. Methods The transient process of polarity reversal is analyzed, considering the anisotropic property of oil immersed press board, a new finite element model based on Galerkin method is presented and verified. The model developed is applied to calculate the electric field distribution in four typical winding end structures of the converter transformer. Results\ The whole ring structure possesses the best insulation characteristics. Conclusion\ By introducing reasonable insulation components, insulation strength with the same surrounding sizes can be improved more than 30%.
基金Project(61275174)supported by the National Natural Science Foundations of ChinaProject(20100162110068)supported by the Doctoral Program of Higher Education of China
文摘Based on Fabry model and finite-different time-domain(FDTD) method, the plasmonic structure composed of a metal-insulator-metal(MIM) bus waveguide and a side-coupled resonator was investigated. It is found that the transmission features can be regulated by the cavity width and coupling distance. Electromagnetically induced transparency(EIT)-like transmission can be excited by adding an identical resonator on the pre-existing structure. Combining the foregoing theoretical analysis with coupled mode theory(CMT), the formation process of the EIT-like transmission was detailedly analyzed. EIT-like transmission can also be excited in plasmonic structure with two detuned resonators. By altering the structure parameters, the transparency window can be purposefully modulated. With the merits of compact structure and simplicity in fabrication, the proposed structures may have a broad prospect of applications in highly integrated optical circuits.
文摘In this work we show the influence of the edge-effect on the electric field distribution and, hence, on the inner and outer capacitance in an inclined-plate capacitor system surrounded by an insulating medium taking into account the thickness of the conducting plates for a complete set of dimensions and insulating characteristics. Where available, we compare our results with previously published works. Finally, using statistical tools, we obtain approximate expression for computing the relationship between capacitance and insulation material characteristics, insulation gap, plate dimensions and angle.
基金Project(2009CB724504)supported by the National Basic Research Program of China
文摘The oil-pressboard insulation is a typical composite insulation system widely used in the design and manufactory of large power apparatus. The implement of oil-pressboard insulation may lead to surface electrification and discharge at the interface under certain condition. It is of significant importance to take an insight into the phenomenon occurring at the interface. Through experiment, the pressboard is found as a porous material. The interface changes abruptly from bulk pressboard to the bulk oil as a result of the porous structure. A new model is proposed which divides the interface into bulk oil region, transition region, and bulk pressboard region. The width of the transition region is decided according to the microtome figure. The effective permittivity of the transition region is calculated using a new model based on fractal theory. The model is validated and compared with previous calculation model. The effect of the existence of transition region on the electric field distribution is discussed.
文摘The purpose of this paper is to show the influence of the edge-effect on the electric field distribution, and hence on the inner capacitance and outer capacitance of a cylindrical capacitor surrounded by an insulating medium. To generalize the results, a two-dimensional axisymmetric finite element model of a cylindrical capacitor has been generated and the problem has been resolved taking into account the distance between the conductors for a complete set of dimensions. The available obtained results have been compared with previous published works. Finally, using statistical tools, the mathematical expression for computing the relationship between capacitance and insulation gap and cylindrical plates dimensions has been obtained.
