| Abstract: | A low voltage circuit breaker (LVCB) is an important piece of protection equipment which will
switch off the fault current in a power system. The moving contact of a low voltage circuit
breaker with a higher rated current consists of two parallel contacts. Therefore, the convection
effect on the air arc evolution process in a two parallel contact system is analyzed. A threedimensional
(3D) magneto–hydro–dynamic (MHD) model of arc simulation is built. In this
model, the anode consists of two parallel contacts and a bonding conductor. A nonlinear
voltage–current density characteristic is employed to represent the near-anode and near-cathode
voltage. The current density, arc voltage and currents through every contact are obtained. The
influence of convection and conduction on the arc evolution process are quantitatively
calculated. The displacements of the arc roots are obtained and the asymmetry of the arc root
motion is analyzed. The arc evolution process of a two parallel contact system is preliminarily
revealed. |
