Analysis on FRP rod of composite insulators by XPS

Composite insulators are widely used in transmission lines. Performance degradation of material is more and more urgent with operation time increases. In China Southern Power Grid, some composite insulators in-service suffer partial abnormal temperature rise which has been a serious potential hazard to operation of transmission lines. In this paper, a 500 kV AC composite insulator with partial abnormal temperature rise, was analyzed. By dissecting these insulators, FRP rod corrosion with varying degrees were found along the string. After that, chemical compositions on FRP rod corrosion surface were examined by XPS (X-Ray Photoelectron Spectroscopy). Test results showed that the basic elements, carbon, nitrogen and oxygen changes according to certain rules and the chain number of Si-O increases when corrosion degree aggravate. Analysis on change of chemical element reveals that the FRP rod corrosion of the composite insulators with partial abnormal temperature rise is mainly due to oxidation.