中国物理B ›› 2024, Vol. 33 ›› Issue (1): 15204-15204.doi: 10.1088/1674-1056/acd7cb

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Fluid-chemical modeling of the near-cathode sheath formation process in a high current broken in DC air circuit breaker

Shi-Dong Peng(彭世东), Jing Li(李静)†, Wei Duan(段薇), Yun-Dong Cao(曹云东), Shu-Xin Liu(刘树鑫), and Hao Huang(黄浩)   

  1. Key Laboratory of Special Electric Machine and High Voltage Apparatus(College of Electrical Engineering), Shenyang University of Technology, Shenyang 110870, China
  • 收稿日期:2023-02-12 修回日期:2023-05-10 接受日期:2023-05-23 出版日期:2023-12-13 发布日期:2023-12-20
  • 通讯作者: Jing Li E-mail:lijing@sut.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 51977132), Key Special Science and Technology Project of Liaoning Province (Grant No. 2020JH1/10100012), and General Program of the Education Department of Liaoning Province (Grant No. LJKZ0126).

Fluid-chemical modeling of the near-cathode sheath formation process in a high current broken in DC air circuit breaker

Shi-Dong Peng(彭世东), Jing Li(李静)†, Wei Duan(段薇), Yun-Dong Cao(曹云东), Shu-Xin Liu(刘树鑫), and Hao Huang(黄浩)   

  1. Key Laboratory of Special Electric Machine and High Voltage Apparatus(College of Electrical Engineering), Shenyang University of Technology, Shenyang 110870, China
  • Received:2023-02-12 Revised:2023-05-10 Accepted:2023-05-23 Online:2023-12-13 Published:2023-12-20
  • Contact: Jing Li E-mail:lijing@sut.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 51977132), Key Special Science and Technology Project of Liaoning Province (Grant No. 2020JH1/10100012), and General Program of the Education Department of Liaoning Province (Grant No. LJKZ0126).

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摘要： When the contacts of a medium-voltage DC air circuit breaker (DCCB) are separated, the energy distribution of the arc is determined by the formation process of the near-electrode sheath. Therefore, the voltage drop through the near-electrode sheath is an important means to build up the arc voltage, which directly determines the current-limiting performance of the DCCB. A numerical model to describe the near-electrode sheath formation process can provide insight into the physical mechanism of the arc formation, and thus provide a method for arc energy regulation. In this work, we establish a two-dimensional axisymmetric time-varying model of a medium-voltage DCCB arc when interrupted by high current based on a fluid-chemical model involving 16 kinds of species and 46 collision reactions. The transient distributions of electron number density, positive and negative ion number density, net space charge density, axial electric field, axial potential between electrodes, and near-cathode sheath are obtained from the numerical model. The computational results show that the electron density in the arc column increases, then decreases, and then stabilizes during the near-cathode sheath formation process, and the arc column's diameter gradually becomes wider. The 11.14 V—12.33 V drops along the 17 μm space charge layer away from the cathode (65.5 kV/m—72.5 kV/m) when the current varies from 20 kA—80 kA. The homogeneous external magnetic field has little effect on the distribution of particles in the near-cathode sheath core, but the electron number density at the near-cathode sheath periphery can increase as the magnetic field increases and the homogeneous external magnetic field will lead to arc diffusion. The validity of the numerical model can be proven by comparison with the experiment.

关键词: near-cathode sheath, atmospheric pressure air arc, fluid-chemical model, high current, DC air circuit breaker (DCCB)

Abstract: When the contacts of a medium-voltage DC air circuit breaker (DCCB) are separated, the energy distribution of the arc is determined by the formation process of the near-electrode sheath. Therefore, the voltage drop through the near-electrode sheath is an important means to build up the arc voltage, which directly determines the current-limiting performance of the DCCB. A numerical model to describe the near-electrode sheath formation process can provide insight into the physical mechanism of the arc formation, and thus provide a method for arc energy regulation. In this work, we establish a two-dimensional axisymmetric time-varying model of a medium-voltage DCCB arc when interrupted by high current based on a fluid-chemical model involving 16 kinds of species and 46 collision reactions. The transient distributions of electron number density, positive and negative ion number density, net space charge density, axial electric field, axial potential between electrodes, and near-cathode sheath are obtained from the numerical model. The computational results show that the electron density in the arc column increases, then decreases, and then stabilizes during the near-cathode sheath formation process, and the arc column's diameter gradually becomes wider. The 11.14 V—12.33 V drops along the 17 μm space charge layer away from the cathode (65.5 kV/m—72.5 kV/m) when the current varies from 20 kA—80 kA. The homogeneous external magnetic field has little effect on the distribution of particles in the near-cathode sheath core, but the electron number density at the near-cathode sheath periphery can increase as the magnetic field increases and the homogeneous external magnetic field will lead to arc diffusion. The validity of the numerical model can be proven by comparison with the experiment.

Key words: near-cathode sheath, atmospheric pressure air arc, fluid-chemical model, high current, DC air circuit breaker (DCCB)

中图分类号:  (Arcs; sparks; lightning; atmospheric electricity)

  • 52.80.Mg
52.40.Hf (Plasma-material interactions; boundary layer effects) 52.65.Kj (Magnetohydrodynamic and fluid equation)