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Insulating liquid, because of high breakdown strength and superior self-recovery property, is widely applied to intense electron beam accelerator, transformer, and superconducting fault current limiters, etc. However, the formation of bubbles caused by heat transfer in power equipment seriously hurts the performance of the insulating strength in liquid. The objective of this paper is to study the...
SCF N2 may have good dielectric properties, so that it has drawn great attention from the scientists worldwide. In this paper, the rod-plate electrode model of 5mm gap with DC voltage was established, and the breakdown process of the SCF N2 was studied under the SC condition with the fluid dynamics method according to the gas-dielectric discharge principle. The results show that the breakdown voltage...
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...
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...
Positive and negative discharge mechanisms in atmospheric air have been numerically analyzed using a fully coupled finite element analysis. Until now, many research works have examined discharge analyses, but the discharge mechanism has not yet been explained in detail numerically. In a positive discharge, the electric field intensity at the streamer head can be enhanced owing to the superposition...
A perforated-aluminium plate electrode has been studied with the aim of enhancing the stability of the glow discharge at atmospheric pressure. A proven simulator has been used (Ansoft-Maxwell 2D) and a significant increase in Electric Field Strength (EFS) is observed using perforated aluminium, due to its sharp edges. Meanwhile, practical investigation also shows that the discharge configuration with...
It is necessary to research live working on UHV electrode line, so as to support DC UHV maintenance. As the electrode line of Zhengzhou converter station for example, the ground faults overvoltage on BP and GR modes were calculated. The maximum switching overvoltage was 288kV under the condition of live working. It was determined by the grounding fault of high end YY converter valves. The switching...
This paper presents an experimental analysis and underlying mechanism of positive and negative pulsed corona discharge induced atmospheric non-thermal plasma. We designed a system based on point-plane configuration to produce direct corona discharge plasma (DCP) and hybrid corona discharge plasma (HCP) systems. The polarity effect of corona discharge for surface modification application on rice seeds...
Scientists and engineers are focusing to purify industrial and other polluted water for drinking, industrial and agriculture purposes. High Voltages are being used to invent different techniques for purification of industrial waste water. In this research, a high voltage Corona discharge method is proposed for the treatment of industrial waste water. The aim is to achieve microbial disinfection, removal...
With the expansion of electrical grids, power equipment are required to operate at high voltages. This was coincided with the trend to develop compact power equipment for the sake of space saving. As a result, insulating materials will be exposed to high electric fields. So, there is a need to examine partial discharge (PD) behavior of different insulation defects when operating under high electric...
With the purpose of improving the efficiency of anaerobic digestion for waste activated sludge, μs-Pulsed electric field (μs-PEF) has been employed for pretreatment on waste activated sludge and its features of low energy consumption and high efficiency make it a promising method for industry application. In this work, DC corona has been used to assist the μs-PEF treatment on the sludge and the treatment...
To investigate the motion and discharge behavior of free conducting linear particles in DC GIL, a coaxial cylindrical electrode is set up, with a high-speed camera to observe the motion and air-gap breakdown of the particles. The research work studies the charging behavior of the particle under DC voltage, then analyzes the particle's lifting voltage theoretically and experimentally. Two different...
External insulation characteristic is the key issues in the design and operation process of high voltage transportation and transfer facilities, whose fundamental base is the breakdown characteristic of air gap. Applying artificial intelligence algorithm using machine learning to design external insulation of transmission line is one of the new directions in the study of external insulation. Therefore,...
Generally, as using the up-and-down method to research the discharge character of SF6 under impulse voltage, the requirement for dispersion of breakdown voltage is less than 3%, which guarantees the reliability of experimental data. But it is found that the dispersion of SF6 breakdown voltage, comparing with other gases, is usually large and even larger than 5%. This research has been still lack of...
This paper presents an optimization of the waveguide-supplied coaxial-line-based nozzleless microwave plasma source. This field applicator operated at a frequency f equal to 915 MHz at an atmospheric pressure. The optimization objective was to maximize an efficiency of power transfer from electric field to plasma inside this device. In the optimization we used a model of plasma which was determined...
The characteristics of positive and negative dc corona have been widely studied; however, the development process experienced of dc corona with the voltage is still unclear. This paper carried out dc corona discharge experiments under different dc voltages on the needle-plate model. Results show that positive corona gradually experienced the discharge stages of burst stream, periodic stream, glow...
High energy storage performance and discharge properties of (Pb0.98La0.02)(Zr0.45Sn0.55)0.995O3 antiferroelectric (AFE) thick films with thickness of 85µm fabricated via a rolling process were investigated by dielectric properties and discharge performance, and the influence of electric field and electrode areas on the discharge properties was emphasized. Energy storage density and the first current...
Gas switch plays a key role in the pulsed power system. In this paper, we observed the discharge process of a particle beam triggered gas switch at the lowest working coefficient. The temporal and spatial evolution of particle beam was captured in real time and the velocity curves of particle beam under different gas pressures were obtained. And the triggering mechanism of the gas switch was analyzed...
SF6 is applied in high-voltage equipment due to its excellent insulating and arcing performance. However, a partial discharge is often caused by some insulation defects. Under partial discharge, The decomposition products including SO2F2, SOF2, SO2, CF4, CS2, will be formed. The types, content, and change trend of products will encounter serious disagreements due to the difference of discharge type...
In an inhomogeneous electric field, there are several kinds of discharge modes existing in microsecond-pulse gliding discharges. In this paper, we investigate mode transition among different discharge modes and the effects of pulse repetition frequency (PRF) and gap distance on microsecond-pulse gliding discharge by measuring the voltage-current waveforms and discharge images. Experimental results...
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