Assessing the integrity of vintage ceramic insulators

New research performed on old ceramic insulators indicates that such insulators are often weaker electrically and mechanically than expected and may create significant maintenance and reliability problems for electric power utilities. Results of tests on insulators removed from service revealed that mechanical, electrical, and material aging of the vintage insulators was significant. This paper describes the findings obtained to date on the condition evaluation of vintage insulators based on the laboratory tests. While research continues, preliminary conclusions suggest that the estimated useful service life for dead-end insulators is from 60 to 75 years, and for suspension units it is from 75 to 90 years.