Electric Field Distribution Study of Hexagonal and Pentagonal Electrode Geometries

XLPE is widely used as an insulating material in electrical systems due to its excellent dielectric properties. However, the effectiveness and dependability of the insulation might be severely impacted by the existence of voids inside it. The objective of this research is to simulate the electric field intensity in an XLPE matrix under varying voltages (15 kV, 20 kV, and 25 kV), with a focus on assessing cable aging. The study aims to examine how void size and void location influence the electric field distribution within the XLPE material. Additionally, the research seeks to explore the impact of void presence on stress concentrations and the electric potential drop within the defect area. To achieve these objectives, the study utilizes COMSOL Multiphysics software and the Finite Element Method (FEM) for the simulations. The simulation process considers different void sizes and varying distances between voids and electrodes. The electric field distribution is analyzed under the different voltage conditions to observe the effects of voids on the electric field and potential drop. The study highlighted that void location significantly impacts electric field distribution, with voids positioned closer to high-voltage electrodes resulting in higher electric field intensities, while voids located farther away exhibit lower field intensities. Additionally, the comparison between the absence and presence of voids showed that voids create stress concentrations, resulting in a more drastic drop in electric potential within the void-defect area. The examination of void location on electric field intensity has revealed the significant impact of void positioning on the distribution of electric fields, emphasizing the importance of precise insulation design and void detection strategies.

This paper presents the results of electric field and potential distributions simulation along surface of silicone rubber polymer insulators.Finite element method (FEM) is adopted for this paper.Identification of the electrical field and the potential distributions at the dielectric insulation has always been important; The water droplets increase the electric field strength at the insulator surface because of their high permittivity and conductivity, at first the results of water droplets existing on the surface of silicone rubber materials has been investigated and electric field distribution along the surface are shown.Then Different Thickness and conductivity of pollution layer on polymer insulator has been considered and electrical field distribution has been analyzed.

Analysis of circular shape distributed piezoelectric actuators

Transcranial Magnetic Stimulation (TMS) treatments have been employed in hospitals. Conventional figure-8 coils can only stimulate a highly localized area, and it is difficult to stimulate specific points accurately without an infrared camera system that is large and expensive. To ease patients' burden, we suggest home treatment with a smaller driving circuit and a smaller positioning system that has an accuracy of approximately 5 mm; this is critical for figure-8 coils. Thus, a wide focus coil is required. In the present study, we propose a new coil named the double-D coil. The radius of side elements and the number of coil turns were defined based on scalar potential finite difference method simulations. The distribution and intensity of electric field were simulated based on finite element method. We also conducted the simulations using brain models constructed from MR images to evaluate its robustness against the coil positioning error. Finally, we developed the double-D coil by using a 3D printer and measured the magnetic flux density. The results show that the double-D coil induced an electric field in an expanded area. This was enough to be applied to a smaller positioning system and the intensity of the electric field was improved at more than 16 mm from the coil surface in the simulation. In the brain model from the MR image, the mean value of the electric field by the double-D coil was 1.2 times stronger than that of the figure-8 coil. The double-D coil created by a 3D printer induced a similar magnetic field to the simulation. That indicates the efficiency of the double-D coil at more than 20 mm from the coil surface.

Pulsed power equipment is often characterized by high energy density and field intensity. In the presence of strong electric field intensity, charge accumulation within insulators exacerbates electric field non-uniformity, leading to potential insulation breakdown, thereby posing a significant threat to the safe operation of pulsed power equipment. In this manuscript, we introduce nonlinear composite materials with field-dependent conductivity and permittivity to adaptively regulate the distribution of the pulsed electric field in insulation equipment. Finite-element modeling and analysis of the needle-plate electrodes and high-voltage bushing are carried out to comprehensively investigate the non-uniformity of the distribution of the electric field and the homogenization effect of various nonlinear materials in the presence of pulsed excitations of different timescales. Numerical results indicate that the involvement of nonlinear composite materials significantly improves the electric field distribution under pulse excitations. In addition, variations in the rising time of the pulses affect the maximum electric field intensity within the insulators considerably, but for pulses of nanosecond and microsecond scales, the tendencies are the opposite. Finally, via the simulations of the bushing, we illustrate that some measures proposed for improving the uniformity of the electric field under low frequencies, e.g., increasing the length of the electric field equalization layer and the distance of the underside of the electric field equalization layer from the grounding screen, are still effective for the homogenization of pulsed electric field.

Submarine cables are widely used in submarine power grid systems, and the operating environment is complex and harsh. Anchor damage is the most fatal factor affecting the safe and stable operation of submarine cable lines. In this paper, the finite element analysis is used to study both the electric and magnetic field distribution of submarine cables to evaluate the degree of anchor damage. Process principles of the two working conditions, anchor drop and anchor drag, are considered and described respectively. In the simulation environment, the 2D finite element model of 110 kV single-core AC submarine cable is built, simulating the anchor damage through longitudinal compression and overall deformation of the stressed section. After solving the electric and magnetic field distribution of the insulation layer, the correlation between the electric field distribution, magnetic field distribution and the deformation degree of anchor damage are finally established. Results show that the deformation of submarine cables caused by anchor damage lead to uneven distribution of both electric field strength and magnetic flux density in the insulation layer. The compression of the cable in the stress direction results in the thickness reduction of the material, thus weakening its magnetic shielding ability. With the simulation conclusion, the internal electric and magnetic field contribution of the submarine cable insulation layer can be inferred according to the insulation deformation degree, which contributes to the status evaluation of the submarine cable after the anchor damage and further ensures the safety and reliability of submarine cable operation.

In this paper, electric field, potential and temperature distributions of normal and fog type insulators were examined. These insulators were modeled in 3D. Simulations were made with COMSOL Multiphysics program using Finite Element Method. The pollution layer was modeled by a layer of 0.5 mm thickness on the insulator surface and the conductivities of the insulator's upper and bottom layers were varied from 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−6</sup> and 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−3</sup> S/m values. Potential and electric field distributions at 11 kV (rms) for clean, uniform and non-uniform pollution conditions and the temperature distributions at 11-15-20 kV (rms) for clean and uniform pollution conditions were examined. The results showed that when the pollution layer conductivity increased, the potential distribution approached the linear state and the electric field strength decreased. The temperature values increased with the applied voltage and conductivity increase.

Atmospheric electric field is closely related to the thunderstorm, climate change, air pollution and solar activity. The detection of atmospheric electric field altitude distribution on special terrain is of great significance for the research of atmospheric electricity. On 12 September 2020, the Honghu special team of Chinese Academy of Sciences mounted the atmospheric electric field instrument on the air sounding balloon, and carried out the detection experiment of the high distribution of atmospheric electric field in the Dachaidan area of Haixi Mongolian-Tibetan Autonomous Prefecture in Qinghai Province. This paper has introduced the electric field instrument, experimental process, experimental results and discussion. The convex part in the middle of the atmospheric electric field curve corresponds to the electric field instrument passing through the clouds. The curve was devided into three sections. These three sections were fitted respectifly. The results show that the main influencing factors of the atmospheric electric field at different altitudes are different, and their distribution laws are also different. In addition, charged clouds can make the overall intensity of the atmospheric electric field increased, while the altitude distribution of the atmospheric electric field in the charged cloud layer is still in accordance with the exponential law.

The atmospheric pressure plasma jets have been widely used in material modification and biomedicine. In this study, the electric field distribution and influencing factors of penetrating materials under atmospheric pressure plasma jet (APPJ) acting on different materials were systematically studied by electro-optical effect measurement technique. In the experiment, alumina ceramic, quartz glass, polystyrene plastic and pig ear back skin were used as media, and the effects of the medium equivalent capacitance, applied voltage parameters (amplitude, frequency, pulse width), gas environment and secondary discharge on the electric field intensity were investigated. The results show that the dielectric equivalent capacitance is positively correlated with the electric field strength, and the peak electric field increases significantly with the increase of dielectric constant. The increase of applied voltage amplitude significantly enhances the electric field intensity, and as the frequency increases, the peak electric field intensity first increases and then decreases. Pulse width modulates electric field persistence that shorter pulses accelerate field decay, whereas longer pulses maintain field intensity throughout their duration. In addition, the existence of secondary discharge significantly changes the time evolution characteristics of the electric field, and the intensity of the reverse electric field is closely related to the equivalent capacitance of the medium.

The electric field distribution within a microwave plasma chemical vapor deposition (MPCVD) reactor determines the quality of synthetic diamonds. In this study, we aimed to facilitate diamond deposition for various demands by designing a rectangular MPCVD reactor that can balance and regulate the electric field intensity and uniformity in the deposition region. Establishing and utilizing a 3D numerical model, we analyzed the electromagnetic field and plasma distributions of three reactor candidates. One promising candidate was optimized and compared with two cylindrical cavities, each having a diameter equal to the width and diagonal length of the rectangular cavity, respectively. The optimized rectangular reactor combined the TM011, TM021, and TM031 modes, exhibited a high-intensity and uniform electric field in the deposition region without other hot-spot regions, and demonstrated high-density plasma and uniform gas distribution. Operating at 2.45 GHz, the reactor generated a maximum electric field intensity of 2 × 105 V/m, and the hydrogen plasma reached a maximum electron density of 5.9 × 1017 m−3 over an effective area of 4.0 × 103 mm2 at 5 kW power and 20 kPa pressure. These findings highlight the potential of the rectangular reactor design, which exhibits a novel microwave modes coupling mechanism, enabling redistribution of microwave energy, and achieves higher electric field intensity in the deposition region compared with traditional cylindrical reactors. The study emphasizes the significance of the rectangular reactor for the growth of demand-specific diamonds.

Electric field distribution and performance optimization of high-speed train cable terminal with internal defects

This work is devoted to the modeling of streamer discharge, propagation in liquid dielectrics (water) gap using the bubble theory. This of the electrical discharge (streamer) propagating within a dielectric liquid subjected to a divergent electric field, using finite element method (in two dimensions). Solution of Laplace's equation governs the voltage and electric field distributions within the configuration, the electrode configuration a point (pin) - plane configuration, the plasma channels were followed, step to step. The results show that, the electrical discharge (streamer) indicates the breakdown voltage required for a 3mm atmospheric pressure dielectric liquid gap as 13 kV. Also, the electric potential and field distributions shown agreement with the streamer growth, according to the simulation development time.

Epoxy resin insulators are widely used on the roof of high-speed trains. However, epoxy resin materials will produce air gaps during design, pouring and other operations. Air gaps are prone to partial discharge under high pressure, which threatens the safe operation of train-set. In this paper, the epoxy resin insulator on the roof of the train-set is taken as the research object, and the three-dimensional model of the epoxy resin insulator with air gap is made to simulate the electric field environment of 27.5kV on the roof epoxy resin insulator. The change of the maximum electric field intensity on the air gap surface when the air gap span, length and width change, and the influence of the change of air gap parameters on the electric field distribution near it are analyzed. The simulation results show that the change of air gap span, length and width seriously affects the surrounding electric field intensity. During the change of the air gap span, the electric field intensity on the air gap surface gradually increases with the increase of the span. When the air gap size changes, the maximum electric field intensity on the surface is 3.41 times that without defects.

This research is conducted to analyze the efficiency of dielectric heating by increasing the input ports which are to be symmetrically model on the electrode plate. This analysis is considering of the electric field distribution and intensity in dielectric loads. The electric fields are caused by the electric power on electrode plates of the input ports to improve the thermals temperatures and electric field distribution of dielectric loads. The dielectric loads are the grains and pests, the rice and rice weevils are the target dielectric materials. To investigate the heating predicted by the theoretical model, the electric field distribution and intensity are analyzed by using the finite difference time domain method. The results demonstrate that the efficiency of the dielectric heating exterminated pests and temperature of grains without losing the quality. The advantage of the method is being able to be utilized for the dielectric heating applications to pest control and control the appropriate temperature of the grains in the future.

Based on electro-magneto-rheological (EMR) effect, this paper presents a novel micro machining method to form an instantaneous tiny-grinding wheel to polish the surface of optical glass, ceramic and other rigid-fragile materials under both electric and magnetic field. Experiments were conducted to reveal the synergistic effect of electrorheological and magnethorheological effect, and the effects of process parameters, such as intensity of electric field, intensity of magnetic field, working time, machining gap between the workpiece and the needle-like tool, on material removal rate of glass surface. Experimental results confirm the effectiveness of the micro machining technique with EMR effect-based tiny-grinding wheel and the machining efficiency under the combination of electric and magnetic field is much greater than the one under applied external electric or magnetic field. The material removal rate of workpiece is directly proportional to the intensity of external electric field and will maintain stable when the voltage of external electric field reaches 2000v, while the material removal rate is directly proportional to the intensity of external magnetic field. The material removal rate markedly descends with the increase of the machining gap. In addition, the working time is directly proportional to the amount of material removal of workpiece, but inversely proportional to material removal rate.