Critical Polymer Defects

Paul Lyons, PE

“When I detect severe activities on polymer insulators – I know that these are distinct signs of problems that either exist or will develop” says Mr. Paul Lyons from L&H engineering, Ofil’s representative in North America. Mr. Lyons’ statement is reinforced by EPRI’s inspection guide that indicates that almost all coronas on polymers are categorized under the “priority replacement” category.

Fig 16 - 17:
230kV Transmission Line Polymer Strain Insulator. Defect: Corona on olymer material. Issue: Failure of insulator.


Fig 18-19:
Taken in a 230 kV Substation. Fig. 21 is an example of a polymer insulator that lacks a corona ring and corona is clearly detected. Fig. 20 shows a polymer insulator with a corona ring and, as expected, no corona activity. Fig. 22 is an example of corona on a polymer insulator with a corona ring.    --up>