Effect of mechanical stress on fast pulse-like conduction in XLPE based materials

The aim of this paper is to investigate the relationship between mechanical stress and a new conduction mechanism discovered recently, that is conduction through fast charge pulses in insulting polymers. Theories and experimental data suggested that such pulses constitute charge solitons moving in the insulation bulk thanks to the induced compressive force applied to the natural relaxation of the polymer chains. This paper supports such picture. Experimental tests carried out under mechanical stress, in fact, show that charge pulse transport is significantly affected by insulation compression. In particular, charge pulse amplitude decreases and positive pulses disappear as mechanical stress is increased. On the contrary, negative pulse mobility increases with the applied stress.