Influence of Copper Vapor on Low-Voltage Circuit Breaker Arcs During Stationary and Moving States

Abstract

The influence of copper vapor on the low-voltage circuit breaker arcs is studied. A three-dimensional (3-D) magnetohydrodynamics(MHD) model of arc motion under the effect of external magnetic field is built up. By adopting the commercial computational fluid dynamics (CFD) package FLUENT based on control-volume method, the above MHD model is solved. For the mediums of air-1% Cu and air-10% Cu, the distributions of stationary temperature, pressure, electrical potential and the arc motion processes are compared with those of a pure air arc. The copper vapor diffusion process in the arc chamber and the distribution of copper vapor mass concentration are also simulated. The results shows that the copper vapor has a cooling effect on the arc plasma and can decrease the stationary voltage as well. Moreover, the presence of copper vapor can decelerate the arc motion in the quenching chambers. The maximal copper vapor concentration locates behind the arc root because of the existence of a "double vortex" near the electrodes.

Overview of Current Research into Low-Voltage Circuit Breakers

“…These models are generally questionable: how can a 3D object such the arc created in a LVCB be represented in 2D? Nevertheless, since the end of the nineties, a lot of papers propose 3D transient models for LVCB [21,[24][25][26][27][28]. For the arc description, these models generally consider the plasma as an electrical Newtonian fluid which can be described by Navier -Stokes fluid equations and potential scalar and vector equations.…”

“…In a Cartesian system (Ox, Oy, Oz), the plasma is described in terms of temperature T, pressure P, velocities components (v x , v y , v z ), potential scalar V, potential vector components (A x , A y , A z ) and other deduced variables such the self-induced magnetic field (B x , B y , B z ) or the current densities (j x , j y , j z ). If mixtures of gases are taken into account, a mass fraction equation must also be solved [24]. All these equations are written in the form of the generalized equation (II-1)…”

“…Nevertheless, metal vapors also come from the electrodes (no plastic vapors are considered). A recent paper of Ma Q et al [24] reports the study of LVCB (working at atmospheric pressure with I = 150A) in the presence of copper vapors coming from its electrodes. To achieve this study, the authors calculate the mass fraction of copper in the air plasma.…”

Three-Dimensional Simulation of Plasma Deformation During Contact Opening in a Circuit Breaker, Including the Analysis of Kink Instability and Sausage Instability

“…Owing to the excellent dielectric strength and interruption performance of SF 6 , it is widely used in gas circuit breakers (GCB) and gas insulated switchgear (GIS), especially for the high voltage class above 110 kV. Therefore, it is very necessary to investigate the SF 6 arc interruption process in a high voltage circuit breaker in order to aid the design of products with higher performances and lower developmental costs [1,2] . During the past 20 years, many researchers of SF 6 high voltage circuit breaker have developed arc models based on magnetohydrodynamics (MHD) [2∼4] .…”