The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Corona discharge due to a conductive particle in highvoltage system is analyzed using a coupled equation, which consists of Poisson's equation for electric field distribution and a discharge equation for space charge density variation. The charge of a conductive particle is calculated using the finite element method, and the electric force acing on the particle is obtained using the calculated result...
The insulation characteristics of solid materials in high voltage switches directly affect the service life of these switches, which is of great significance to the reliability of power system. The electrical aging lifetime of epoxy resin materials in solid insulation switches is studied in this paper. The electrical aging lifetime test is carried on the epoxy resin materials at room temperature with...
High voltage SF6 circuit breaker must meet the breaking requirement for large short-circuit current, and ensure absence of breakdown after breaking small current. A 126kV high voltage SF6 circuit breaker was used as the research object in this paper. Based on the calculation results of non-equilibrium arc plasma material parameters, the distribution of pressure, temperature and density were calculated...
In this work, we theoretically investigate the L3 cavity with three missing holes in the center. The Photonic cavities have an ultra-low index contrast and are fabricated by SiO2/ZrO2 or SiO2/TiO2 in which the refractive index varies in the range of 1.51 to 1.58 at λ =1.55 μm. We show that cavity modes can be differently tuned depending on the size and the position of the first hole adjacent to the...
The objective in this paper is the introduction of a new method in the design of high voltage insulators by exploiting a meta-heuristic optimization. Indeed, a neural network is used for the prediction of the value of the tangential electric field at the high voltage pin (the area where the value of the electric field is maximum), which will then serve as an objective function to be minimized by the...
The objective of this paper is to determine the dependence of field enhancement factor β on power frequency (50 Hz) voltage in vacuum. A rod-plane vacuum gap was designed in a vacuum interrupter. Shots of ac power frequency voltage were applied at three vacuum gaps till breakdown occurred and the three vacuum gaps were 1.0 mm, 0.8 mm and 0.5 mm, respectively. The field emission current and applied...
When SF6 was designated as a green house gas to be reduced, there has been a wish to use an alternative insulating gas to replace pure SF6 gas. And a fluoroketon, C5F10O attracts great attention as a potential substitute. In this paper, the breakdown characteristics of C5F10O/CO2 as mixtures in nonuniform electric filed and the variation of the mixing ratio with elevation were studied. The positive...
SF6 has been widely used in electrical industry because of its excellent electrical capabilities. However, due to its extremely high Global Warming Potential (GWP), researchers have done lots of investigations on SF6 alternative gases during the last few decades. Unfortunately, all the substitutions have their own drawbacks and limitations and can't be applied in practice. In this paper, the critical...
CF3I has been recognized as an attractive insulating medium for substituting SF6 gas in high-voltage switchgear insulations, because it has low global warming potential (GWP) and an insulation capability that is 1.2 times greater than that of SF6. In this paper, the AC breakdown tests on CF3I/N2 gas mixture have been completed in a sphere-plate geometry. We reveal the effect laws of mixture content,...
The application of vacuum interrupters and vacuum circuit breakers for higher voltage level is strongly expected. In electrical insulation in vacuum, surface flashover on solid insulator is one of the main problems for the higher voltage vacuum interrupters. In this paper, through the review of our recent researches, we discuss on the initiation and development mechanisms of flashover in the configuration...
This paper reports simulation of punch-through gallium nitride (GaN) insulated gate bipolar transistors (IGBTs) with different drift layer thicknesses of t=12 μm and t=17 μm delivering breakdown voltages of VBD=600V and VBD=700V, respectively. The simulated devices are enhancement-mode with the threshold voltage of +3.5V. The leakage current in proposed devices are in the range of 10−9 A/μm. Using...
High liquefaction temperature and greenhouse effect are two major problems of SF6. To find alternative gas of SF6 becomes an urgency in power industry. In this paper, the insulation characteristics of c-C4F8/N2 are studied. The AC breakdown voltage in slightly non-uniform electric field with different air pressure and mix ratio is measured. The results show that breakdown voltage increases with the...
Due to the characteristics of easy access, non-toxic, stable physicochemical properties and non-combustion supporting, N2 and CO2 gases attract a lot of attention of researchers as a possible substitute for SF6. Based on the gas dynamics equation, considering the collision of charged particles, the arc formation process in mixed gas circuit breaker is simulated from the microscopic point of view in...
This paper presents an optical electric field sensor (OEFS) based on evanescent field characteristics of micro-nano fiber (MNF) and electro-optic effect of electro-optical polymer to solve the problem of large size, large influence on measuring field and low sensitivity in the traditional electric field sensors. The sensor body is fabricated using a MNF coating Special electro-optic polymer. In the...
The short length and graded gap of InGaAs-based diodes with impact ionization are considered. Diode peculiarity is defined by usage region with varying composition. The analysis of diodes operation is performed by Monte Carlo technique. Influence of doping and composition profile on current-voltage characteristic of diode is investigated. The possibility of same direct motion of both types of charge...
As an important part of power system, distribution line directly affects the stability and reliability of power supply. However, the distribution line is easy to be affected by the environmental conditions, in which the lightning-induced voltage is the main factor causing the lightning fault of overhead distribution lines. In this paper, the Agrawal model is selected and the FDTD algorithm is used...
This paper describes a method for the development of a computational tool in order to verify the influence of some parameters of a Lightning Location System (LLS), operating in the Low Frequency (LF) range, in the measurement of electromagnetic waves emissions caused by negative cloud-to-ground lightning. The procedure was used to simulate the propagation of these waves, using as model of return current...
In many studies of lightning flash characterization, the lightning generated electric field measuring system uses a circuit based on the buffer-amplifier LH0033. This circuit was proposed 35 years ago and there is no doubt of its excellent performance to measure the lightning electric field intensity. However, LH0033 is no longer manufactured, making it necessary to find a replacement. This paper...
Knowing the rate of atmospheric electrical activity is fundamentally relevant for human life, and for infrastructures, because these events cause major damages of different nature. In the case of country airports and aerodromes, it is of particular importance on the operation related ramp closures on departing and arriving air traffic and ramp personnel operations in adverse weather conditions. For...
Electronics technologies rely on the control of electric current in solid-state devices. The faster currents can be turned on and off, and the lower the energy dissipated in the process, the higher the performance and efficiency of the system. Here, we review the feasibility of generating and controlling electric current in semiconductors and insulators with few-cycle optical waveforms, within a single...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.