Brittle fracture of FRP rod begins in a small invisible crack on the insulator’s weather shed. Chemical deterioration of insulator’s housing can cause SiR insulators to become conductive and susceptible to corona discharge. Compromised SiR insulators lose their elasticity and become brittle. As soon as the housing is damaged acids and contamination migrate into the FRP rod, they decomposing the resin and corroding the fiberglass. White powder discoloration and the strong odor of Ozone indicate corona activity; yet, the most efficient way to actually be aware of corona activity is by using sensitive and reliable corona cameras.

Brittle fracture happens without any previous warnings. In tension dead end insulators, brittle fractures can be hazardous. In all cases of brittle fractures, the outcome was of unexpected, costly shutdowns.

This video clip was taken in a 161 kV substation. Corona on the shed facing the end fitting developed into arcing, leaving both discoloration and carbonized marks. If left unattended in such a situation, the housing will lose its properties, cracks will appear, the bond will decompose and the insulator will fall.

Early warning and pinpointed information about the existing decaying processes were provided by Ofil’s UViGrapher inspection engineer. The DayCor UVollé handheld corona camera was used during the inspection. Recorded findings were documented using Ofil’s CoronaWise software and reported to the asset manager of a privately-owned substation. Findings assisted the facility in preventing a major loss.