Experimental Investigation of the Interaction of Interrupting Arcs and Gassing Polymer Walls

Gassing polymer walls are used in circuit breakers to improve their interrupting and current limiting performance. The energy of the arc will be partially absorbed by the polymer walls, causing chemical degradation and evaporation. The evaporated gas reaches the arc plasma changing its composition and influencing its burning conditions. The resulting increase on pressure and arc voltage contributes to current limiting and reduction of arcing time. This paper deals with experimental results of the investigation of the interaction between the arc and gassing polymer walls. The simultaneous detection of pressure in the arc chamber, of arc current and voltage and the use of high speed photography and SEM analysis contribute to the characterisation of the influence of the polymer gases on the arc behaviour. The results of the experiments are used to verify numerical models.