The non-thermal plasma created by high voltage pulsed power supply can be used to remove sulfur dioxide in the air, but how to increase the removing efficiency is not clear. It is novel to apply the magnetic field in removing S02 as discussed in this paper. The mechanisms of removing sulfur dioxide by non-thermal plasma along with the application of the magnetic field are analyzed, and the related factors affecting the removal efficiency, such as the magnitude of pulsed voltage, the polarity of the pulse, the layout of the discharge electrode, especially the magnetic field are experimentally investigated. It can be concluded that the purification efficiency is improved significantly by applying the magnetic field.

A new research method is proposed for the medium-voltage (MV) vacuum circuit breaker’s (CB’s) mechanical condition monitoring, which combines the mechanism dynamic features simulation and mechanical condition recognition algorithm based on artificial neural networks (ANNs). This method includes three steps: First, the relations between eigenvalues and mechanical failures of a vacuum circuit breaker (CB) through simulation instead of measurement are obtained. In this paper, the mechanism dynamic features of a vacuum CB in failure are simulated; the simulation results indicate that the parameter that can be monitored—main angle—has different characters for different mechanism failures. Second, the eigenvalues for different failure conditions are described by three parameters. Third, mechanical condition recognition of the MV vacuum CB by an algorithm based on ANN is realized. It is concluded by the work mentioned above, both the known mechanical condition type and the new mechanical condition type of the medium-voltage vacuum CB can be recognized with predetermined reliability.

This paper is devoted to the simulation of the arc plasma in a simplified low-voltage circuit breaker chamber. Based on a group of coupled governing equations, a three-dimensional (3-D) arc plasma model is built and solved by a modified commercial code. Firstly, this paper presents a solution of the stationary state of the arc plasma and discusses the distribution of some parameters throughout the chamber. Secondly, with the ferromagnetic materials included, the balance of the stationary state is broken and a transient course is calculated. In light of the simulation results, the temperature distribution sequence, the arc motion and the plasma jet are then described and analyzed in detail.

It is novel to apply magneticfleld in the indoor air puriflcation by collecting pre-charged suspended particles. Based on experiments and analysis of relative data, the effects of some influential factors (the number of discharge electrode, the polarity and magnitude of discharge voltage, the di rection and magnitude of magneticfleld, the initial velocity of charged particles, the distance between particle collecting plates) on the effciency of air puriflcation are discussed. The results indicate that the puriflcation effciency is improved by applying the proper magneticfleld, -6kV direct current voltage is an optimal voltage and there are optimal magnitudes of the distance between collecting plate and the initial velocity of particles in the puriffcation process.

A dynamic model for a medium-voltage vacuum circuit breaker is constructed using the ADAMS software. The model is used to investigate the mechanical characteristics of the circuit breaker under the influence of electrodynamic forces. The characteristics are also investigated experimentally. The simulated and experimental results are in close agreement. It is shown that electrodynamic force increases the breaking speed of the moving contacts by 0.2m/s. The model can be used to highlight design criteria for the optimal operation of medium-voltage circuit breakers.