Effect of Salt Fog Conditions on Deterioration of Housing Materials for Polymer Insulators in Salt Fog Ageing Test

Salt fog ageing tests are widely conducted for evaluating anti-tracking/anti-erosion performance of housing materials for outdoor polymer insulators. A detailed test method, however, is not yet standardized and round robin tests have been conducted for standardization all over the world. Here we have investigated the effect of fog conditions on the deterioration of silicone rubber under two different salt fog conditions generated by an ultrasonic humidifier and an IEC nozzle. In spite of the same injection rate and the same salinity, comparable results from the viewpoints of leakage/discharge currents and the degree of surface deterioration could not be obtained between the two salt fog conditions generated by the ultrasonic humidifier and the IEC nozzle. Almost comparable test results, however, were obtained under the two salt fog conditions generated by the ultrasonic humidifier and the IEC nozzle after controlling the salt fog particle size distribution.