Development of a FEM simulation of axial magnetic field vacuum arcs

2014 International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)

et al. 2014

Based on a steady 3D Magneto-Hydro-Dynamic (MHD) model, the high-current vacuum arc (HCVA) under combined effect of actual magnetic field (MF) and external transverse magnetic field (ETMF) is simulated. The actual MF is generated by cup-type AMF contact system. The ETMF may cause the deflection of arc column which is the main reason of the contact deflected erosion. According to some experimental results, the electron temperature in HCVA is assumed to be uniform and equal to 3eV. So the MHD model is simplified to improve the simulation efficiency. With the three conservation equations (mass, momentum and energy) of ion flow coupling solved, the spatial distributions of some flow parameters can be obtained. The influence of all three components of the magnetic field is inserted by solving the magnetic transport equations sequentially. Proper boundary conditions are set on the cathode and anode side which separated the cathode spots mixing region and anode sheath region from computation domain respectively. Under the influence of the ETMF, the deflection of the plasma flow can be found which may be helpful to understand the mechanism of the contact deflected erosion.

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

The 3D simulation of high-current vacuum arc under combined effect of actual magnetic field and external transverse magnetic field

Qian

2014 International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)

et al. 2014

“…At so far, only few researchers have done 3D simulation on VAs. Hartmann [8,9] simulated VA with uniform, saddle and bell axial magnetic field (AMF). Wang [10,11] also modeled and simulated VA with 3D MHD model.…”

Section: Introductionmentioning

confidence: 99%

3D numerical simulation of vacuum arc with anode vapor in actual magnetic fields

Huang

2014 International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)

et al. 2014

Characteristics of vacuum arc seriously influence the interruption ability of vacuum switches. In many cases (especially in commercial electrode systems), vacuum arcs are not completely axial symmetrical configuration. So, three-dimensional simulation of vacuum arc is needed. On the other hand, when the interruption current is very high, the anode will be in active state and becomes another source of inter-electrode plasma. In this paper, a time dependent actual magnetic field generated by commercial cup-shaped axial magnetic field (AMF) electrode is simulated. With this magnetic field and the simulation results of anode temperature, the dynamic characteristics of vacuum arc considering anode vapor pressure (also considering simplified cathode spots diffusion and open process of electrode) are obtained. In the simulation results, the magnetic field distribution of commercial cup-shaped electrode is six leaves shape, and so do other parameters. There are some ions pressed by high anode vapor pressure from anode to arc column.

“…In [3], using a commercial finite element method (FEM) software package, ANSYS, the constriction of the vacuum arc current was predicted. The influence of uniform AMF and realistic spatial AMF profiles found in commercial VIs on HCVAs were studied in [4] and [5]. The simulation results indicated that there existed a significant rotational phenomenon in HCVAs under AMF.…”

mentioning

confidence: 99%

3-D Simulation of High-Current Vacuum Arcs Under Combined Effect of Actual Magnetic Field and External Transverse Magnetic Field

Qian

IEEE Trans. Plasma Sci.

et al. 2015

Based on a steady-state 3-D magnetohydrodynamic (MHD) model, the high-current vacuum arc (HCVA) under combined effect of actual magnetic field (MF) and external transverse MF (ETMF) is simulated. The actual MF is generated by cup-type axial magnetic field contact system commonly used in commercial vacuum circuit breakers. The ETMF may cause the deflection of arc column, which is the main reason of the contact deflected erosion. According to some experimental results, the electron temperature in HCVA is assumed to be uniform and equal to 3 eV. Therefore, the MHD model is simplified by neglecting the electron energy equation to improve the simulation efficiency. With the three conservation equations (mass, momentum, and energy) of ion flow coupling solved, the spatial distributions of some flow parameters can be obtained. The influence of all three components of the MF is inserted by solving the magnetic transport equations sequentially. Proper boundary conditions are set on the cathode and anode side, which separated the cathode spots mixing region and anode sheath region from computation domain, respectively. Under the influence of the ETMF, the deflection of the plasma flow can be predicted, which may be helpful to understand the mechanism of the contact deflected erosion. Index Terms-3-D magnetohydrodynamic (MHD) model, magnetic field (MF), numerical simulation, vacuum arcs.