Tracking and erosion resistance of LSR and HTV silicon rubber samples under acid rain conditions

Abstract

Assessment of the material degradation in laboratory similar to field conditions is still a challenge. In the present work an attempt is made to study the effect of environment conditions in service life of polymeric insulators on tracking and erosion resistance. Evaluation of tracking and erosion resistance of Silicone Rubber insulating samples of high temperature vulcanized (HTV) rubber and liquid silicone rubber (LSR) are carried out under AC and positive polarity DC voltage. The samples are treated under normal contaminants as per IEC 60587 and acidic contaminant solution simulating acid rain. The conditions of pollution/ contamination severity level are taken into consideration by maintaining the conductivity approximately 2.5 mS/cm for both solution to observe the effect of acidity alone on the samples, the acidity level is varied to understand the material behavior under acidic case with AC and DC stress application. A new experimental arrangement is set up based on IEC 60587 and ASTM D-2303 standards. The constant voltage method is employed to find the relative tracking performance of silicone rubber samples for different chemical composition. Physico-chemical analysis involving SEM, EDAX and FTIR is carried out on treated samples to understand the surface morphology and chemical changes. A comparative analysis is carried out for the acid rain solution and the standard solution of NH 4 Cl. Further leakage current performance and analysis is carried under both AC and DC stress.