Experimental investigation of cathode spots and plasma jets behavior subjected to two kinds of axial magnetic field electrodes

Wang, Lijun; Deng, Jie; Zhou, Xin; Jia, Shenli; Qian, Zhenghua; Shi, Zongqian

doi:10.1063/1.4947561

Cited by 4 publications

(4 citation statements)

References 23 publications

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“…On the other hand, the electron temperature distribution is related to joule heating. Wang et al [38] gave the change of current density of the cup-shaped electrode. In the initial diffusion process, the anode current density is large and the joule heating is strong, which makes the electron temperature rise.…”

Section: Resultsmentioning

confidence: 99%

Experimental study on dynamic characteristics of charged particles in vacuum arc

Liu,

Yuan,

Liu

et al. 2023

Meas. Sci. Technol.

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The vacuum arc is essentially a process of evaporation, collision and ionization of metal materials to keep burning. Electron temperature and density are important parameters to describe vacuum arc plasma transport. This paper was based on the theory of continuous spectral radiation, combined with the principle of two-colorimetric temperature measurement, and realized 2D calculation and observation of electron temperature and density. The experimental platform for vacuum arc breaking and an optical image acquisition system were established to achieve synchronous acquisition of two wavelengths of arc by imaging separation method. On the basis of partial local thermodynamic equilibrium hypothesis, and obtained the 2D dynamic distribution of the electron temperature and density. The results showed that electron density decayed along the radial direction and the density near anode was lower in the axial direction. The 2D distribution trend of electron temperature was opposite to the density. Electron temperature had a little change and the electron density expands outward in different arcing times. With the increase of current amplitude, the peak value of electron density increased, and the electron density in the arc gap also increased. The measured results could reflect the formation and movement of microscopic particles at the initial diffusion stage.

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Section: Resultsmentioning

confidence: 99%

Experimental study on dynamic characteristics of charged particles in vacuum arc

Liu,

Yuan,

Liu

et al. 2023

Meas. Sci. Technol.

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“…Several previous papers have dealt with the investigation of the behavior patterns of vacuum arcs on TMF contacts [21][22][23]. The AMF contacts were used in the experiments to study cathode spots and plasma jets behavior [24].…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, the research on the velocity of cathode spots can be used to study the characteristics of vacuum arc. At present, most studies are focusing on the expansion characteristics of cathode spots in 50 Hz [23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on the velocity of cathode spots in a vacuum arc with high di/dt

Liu¹,

Yuan²,

Chen³

et al. 2022

J. Phys. D: Appl. Phys.

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With the development of DC transmission and aerospace technology, the demands on the breaking capacity of vacuum circuit breakers under high di/dt condition are getting higher and higher. The breaking capacity of vacuum circuit breakers is determined by cathode spots, which provide electrons and metal vapor to maintain the arc. In this paper, the experiments of cathode spot observation were carried out based on the detachable vacuum interrupter and the cup-shaped axial magnetic field contacts. The images of cathode spot distribution were obtained by an ultra high-speed camera. In the initial expansion stage of arcing, it was discovered that the distribution of cathode spots is ring-shaped and symmetrical. The initial expansion velocity of cathode spot ring is approximately proportional to the value of (di/dt)1/2 and is independent of frequency. During the whole arcing process, the expansion velocity of cathode spot ring rises first and then drops with arcing time. The effects of the magnetic field and metal vapor density on the expansion process of cathode spot were analyzed. Based on the experimental conditions and results, the values of magnetic field and metal vapor density were calculated which can reasonably explain the variation of expansion velocity of cathode spot.

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“…Besides TMF, axial magnetic field (AMF) is also important for the distribution of cathode spots. Several previous experimental research has dealt with the investigation of the behavior of cathode spot in a axial magnetic field [11][12][13][14]. It was discovered that the AMF constrains radial expansion of cathode spots.…”

Section: Introductionmentioning

confidence: 99%

Dynamic characteristics of cathode spots during expansion process in a vacuum arc

Liu¹,

Yuan²,

Chen³

et al. 2022

J. Phys. D: Appl. Phys.

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Cathode spot is the source of plasma and metal vapor which affects the breaking capacity of vacuum circuit breakers. In this paper, the cup-shaped axial magnetic field contacts were used and the images of cathode spots were obtained by an ultra high-speed camera in the experiment. The dynamic characteristics of cathode spots during expansion process in vacuum arc were investigated. Under the conditions of different current amplitudes, different distributions of cathode spots were observed. During the expansion process of cathode spot, there are group spots and individual spots. The group spot only occurs in the cold electrode. The electrons emission characteristics of cathode spot as a function of temperature and electric field was calculated. The formation of group spot is related to the current and electron emission of cathode spot. The cathode spots were identified by Matlab. It was found that the variation of number of cathode spots is consistent with the current. However, at different stages, the reasons for the increase in the number of cathode spots are different, such as the increase in the area of cathode spots in the initial arcing stage and the splitting of cathode spot. It was obversed that the cathode spots are not completely evenly distributed on the cathode surface. The farther away from the center of the contact, the longer the distance between the cathode spots. It is mainly effected by the transverse magnetic field which is generated by the arc column. The closer to the contact edge, the higher the transverse magnetic field at the cathode spot and the higher the expansion velocity of cathode spot.

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Experimental investigation of cathode spots and plasma jets behavior subjected to two kinds of axial magnetic field electrodes

Cited by 4 publications

References 23 publications

Experimental study on dynamic characteristics of charged particles in vacuum arc

Experimental study on dynamic characteristics of charged particles in vacuum arc

Experimental investigation on the velocity of cathode spots in a vacuum arc with high di/dt

Dynamic characteristics of cathode spots during expansion process in a vacuum arc

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