Strength and dependability are the critical attributes on which polymer insulators are measured. They are, in fact, the lifespan of the polymer insulator.
MacLean Power Systems (MPS) evaluated the performance of polymer insulators in service approximately 15 years at 500kV system voltage to assess how the insulators (housing material, seal, etc.) have performed over time, and tried to determine if the insulators are approaching a potential end of life, or if an accurate judgment can be derived on how many more years these insulators can continue to perform.
The 24 MPS insulators evaluated included representative samples from both the east and west coasts; each was set manufactured in 1994 and energized in 1995.
The evaluation verifies that the MPS silicone formulation has performed well and is capable of continuing to do so over the next 15 years.
There were no signs of premature aging or breakdown of the silicone housing on any of the 24 sample insulators. There was no discoloration of the rubber, cracking, chalking, or signs that the material was becoming brittle. The silicone housing is still very hydrophobic across the entire housing on all of the insulators.
MPS insulators withstood the test of time and the resulting material still offered exceptional dielectric characteristics.
Representative polymer insulators from both the east and west coasts were evaluated.