Factors of influence on surface erosion of epoxy resin exposed to electrical discharges

This paper investigates the influence of electrical as well as environmental stresses on surface erosion of polymeric materials used in high voltage insulation. The analyzed electrical stresses are applied voltage magnitude and frequency; whereas the environmental stresses of concern are temperature and humidity of air above sample surface. Suitable electrode arrangement is chosen in order to produce measurable erosion and guarantee the control of the analyzed stressing factors. Discharge intensity is defined by two parameters; total discharge energy and cumulative charge; whereas surface erosion severity is characterized by three quantities; surface eroded area, eroded volume and maximum erosion depth. Surface characteristics are obtained by a laser profilometer. From the obtained results a dependence of erosion severity on these stressing factors can be proven. A strong correlation between discharge intensity and material surface erosion is concluded.