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Xue Zhou

Bio: Xue Zhou is an academic researcher from Harbin Institute of Technology. The author has contributed to research in topics: Arc (geometry) & Electric arc. The author has an hindex of 5, co-authored 27 publications receiving 89 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the complicated arc discharge plasma in a dc power relay has been investigated by using both experimental and numerical approaches, and the authors proposed a simplified model based on the magnetohydrodynamic (MHD) theory to determine the influence of transverse magnetic field on arc motion characteristics.
Abstract: DC power relay is a key electromechanical component widely used in electrical vehicles, photovoltaics, as well as more-electric aircrafts for energy managing, power conversion, and distribution. As the voltage and current increase due to relay switches, arc discharge becomes an unavoidable and significant issue during the operation of the dc high-power relay. Bridge-type contact and external permanent magnets are spontaneously employed in its arc chamber to accelerate the quenching of arc. In this paper, the complicated arc discharge plasma in a dc power relay has been investigated by using both experimental and numerical approaches. Initially, arc dwell and arc restriking characteristics during the arc motion phase are presented by analyzing the voltage and current waveforms and arc images acquired in carefully designed breaking experiments. The arc driven by a transverse magnetic field with a variety of flux densities and the influence of flux densities on arc voltage and dwell are preliminarily discussed based on the experimental results. Then, to reveal the arc physics and to determine the influence of transverse magnetic field on arc motion characteristics, a simplified model based on the magnetohydrodynamic (MHD) theory is built and three cases with different magnetic field are calculated. The simulated arc behaviors including distributions of the temperature and current density are presented. The mechanism underlying the influence of transverse magnetic field on the arc motion is analyzed according to arc root transfer and arc voltage variation. In addition, to understand the formation of the arc restriking, the critical breakdown electric-field strength inside the arc gap is also calculated based on streamer breakdown theory. The parameters in the space occupied by earlier arcs, as predicted by the MHD simulations, are used in the breakdown calculation. Results show that the critical breakdown voltage reduces remarkably along with growth of the operating voltage and breaking current, and the arc dwell time can be reduced by strengthening the external magnetic field within a reasonable extent.

22 citations

Journal ArticleDOI
TL;DR: In this paper, heat transfer and fluid dynamics in the molten pool in silver contacts are coupled with the gas dynamics at the vicinity of static arc to determine the evaporation rate due to static arc.
Abstract: Two mass erosion mechanisms or mass loss modes for electrodes during the repetitive arcing processes should be responsible for the failure of electromagnetic relays, and there are evaporation erosion and sputter erosion. Of these two, the evaporation erosion is believed to be the main failure mechanism for the electrodes used in low-current relays. Unfortunately, there is still no straight-forward model to predict the characteristics of the evaporation process on the electrodes. In this paper, heat transfer and fluid dynamics in the molten pool in silver contacts are coupled with the gas dynamics in the vicinity of arc spot to determine the evaporation rate due to static arc. The influences of input parameters, such as arc current and material properties, on the evaporation rate are analyzed. Of all those parameters, boiling point and thermal conductivity of the electrode are found to be the most significant influences on the evaporation rate. The transfer direction of mass due to electrode evaporation is discussed on the assumption of zero net material loss, and it is found to be directly related to the current and heat flux from the arc to the electrodes. The method used in this paper to evaluate the evaporation erosion characteristics can serve for strategies to alleviate evaporation erosion for relay electrodes.

15 citations

Proceedings ArticleDOI
01 Oct 2014
TL;DR: In this paper, a cuboid permanent magnet is used to provide adjustable magnetic field for accelerating the arc quenching, and the results are of practical value for designing the contact system of a high voltage dc contactor.
Abstract: Supply voltage of the dc power system in an electrical vehicle or an airplane keeps increasing with the increment of their electric energy consumptions, which raises a claim on high voltage contactors or relays. Special design on contact system or arc chamber in the contactor for arc quenching is necessary to meet the requirement of dc high voltage break. In this paper, arc behaviors when a bridge-type contact opens a dc resistive load are studied by analyzing arc shapes and waveforms of arc voltage and current. The power voltage varies from 280 V to 730 V, the current is kept to be 50 A, the material of contact is copper and the arcing gas is air. A cuboid permanent magnet is used to provide adjustable magnetic field for accelerating the arc quenching. Key arc parameters, such as arc durations, arc lengths, arc re-ignitions and the period that the arc stays on contact surface, are obtained as the power voltage increases from 280 V to 730 V and the magnetic field varies from 30 mT to 90 mT. The results are of practical value for designing the contact system of a high voltage dc contactor.

11 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the effects of microstructure on arc erosion resistance of contact materials via the dynamic model was investigated for their application in switches, and the results indicated that the CuO micro-structure of Ag-CuOS showed a lower continuity coefficient (α n c ) and a better continuity than that of Ag -CuOI during the arc erosion process.

52 citations

Journal ArticleDOI
TL;DR: In this article, the microstructures and arc erosion characteristics of Ag-30SnO2 materials were investigated by phase identification and microstructure analysis using the computational fluid dynamics (CFD) method.

28 citations

Journal ArticleDOI
Guangning Wu1, Yue Zhou1, Guoqiang Gao1, Jie Wu1, Wenfu Wei1 
TL;DR: In this paper, an interesting arc crater-centered multicolored subarea on the strip surface was found, which was explained from the aspects of the effect of arc-induced temperature and formation of copper oxide film.
Abstract: Currently, great attention has been paid to the fast development of high-speed railways all over the world. With an increment of running speed, pantograph arcing has become a significant issue, which can threaten the lifespan and service performance of pantograph strip materials severely. Cu-impregnated carbon strip is one of the most widely used strip materials in high-speed railways, while its arc erosion characteristics and mechanisms are still in absence. In this paper, the arc erosion characteristics of Cu-impregnated carbon materials were experimentally studied. The variations in voltage waveforms between electrodes with time were recorded, and the evolution of the temperature distribution of strip was obtained by a thermal infrared imager. The arc erosion surface was examined using a digital camera, a scanning electron microscopy, and energy dispersive X-ray spectroscopy to assess the macroscopic and microscopic morphologies, as well as elemental distributions in or around the arc erosion crater. An interesting arc crater-centered multicolored subarea on the strip surface was found, which was explained from the aspects of the effect of arc-induced temperature and formation of copper oxide film. The arc erosion crater consisted of several overlapped erosion pits, and the mechanism of the pits was understood from the unique microstructure and physical properties of carbon phase and copper phase in the materials. Finally, the formation of spherical copper particles and cracks was illustrated, and their influences on the sliding wear and friction process were discussed.

23 citations

Journal ArticleDOI
TL;DR: In this paper, the complicated arc discharge plasma in a dc power relay has been investigated by using both experimental and numerical approaches, and the authors proposed a simplified model based on the magnetohydrodynamic (MHD) theory to determine the influence of transverse magnetic field on arc motion characteristics.
Abstract: DC power relay is a key electromechanical component widely used in electrical vehicles, photovoltaics, as well as more-electric aircrafts for energy managing, power conversion, and distribution. As the voltage and current increase due to relay switches, arc discharge becomes an unavoidable and significant issue during the operation of the dc high-power relay. Bridge-type contact and external permanent magnets are spontaneously employed in its arc chamber to accelerate the quenching of arc. In this paper, the complicated arc discharge plasma in a dc power relay has been investigated by using both experimental and numerical approaches. Initially, arc dwell and arc restriking characteristics during the arc motion phase are presented by analyzing the voltage and current waveforms and arc images acquired in carefully designed breaking experiments. The arc driven by a transverse magnetic field with a variety of flux densities and the influence of flux densities on arc voltage and dwell are preliminarily discussed based on the experimental results. Then, to reveal the arc physics and to determine the influence of transverse magnetic field on arc motion characteristics, a simplified model based on the magnetohydrodynamic (MHD) theory is built and three cases with different magnetic field are calculated. The simulated arc behaviors including distributions of the temperature and current density are presented. The mechanism underlying the influence of transverse magnetic field on the arc motion is analyzed according to arc root transfer and arc voltage variation. In addition, to understand the formation of the arc restriking, the critical breakdown electric-field strength inside the arc gap is also calculated based on streamer breakdown theory. The parameters in the space occupied by earlier arcs, as predicted by the MHD simulations, are used in the breakdown calculation. Results show that the critical breakdown voltage reduces remarkably along with growth of the operating voltage and breaking current, and the arc dwell time can be reduced by strengthening the external magnetic field within a reasonable extent.

22 citations

Journal ArticleDOI
TL;DR: The challenges faced by battery powered systems are examined, and more general problems are explored, and several real-world embedded systems are explored.
Abstract: The applications and uses of embedded systems is increasingly pervasive. Mission and safety critical systems relying on embedded systems pose specific challenges. Embedded systems is a multi-disciplinary domain, involving both hardware and software. Systems need to be designed in a holistic manner so that they are able to provide the desired reliability and minimise unnecessary complexity. The large problem landscape means that there is no one solution that fits all applications of embedded systems. With the primary focus of these mission and safety critical systems being functionality and reliability, there can be conflicts with business needs, and this can introduce pressures to reduce cost at the expense of reliability and functionality. This paper examines the challenges faced by battery powered systems, and then explores at more general problems, and several real-world embedded systems.

14 citations