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Thanks to the amorphous structure of glass and the unique mechanical properties of the toughening process, toughened glass insulators do not age. The surface compressive stresses induced by the toughening process mean that surface cracks simply cannot develop. It is common practice among utilities to quote the life time of toughened glass insulators as being far above the limit of poles, towers and conductors. In fact, it is the metallic components such as fittings and hardware that dictate this evaluation. Numerous studies on very old toughened glass insulators have shown that the mechanical and electrical values of toughened glass insulators manufactured by SEDIVER do not decrease with time, and stay above original ratings even after 40 years in service. Examples are given as follows:
The Netherlands - 150 kV line at Essent Zuid USA - 500 kV line
at BPA USA - 345kV line at Mid America 80kN insulators were tested after 28 years in service : USA - 500kV line at Pacificorp Malaysia - 132 kV lines
at NEB
Scudai-Sultan.Simail line - marine pollution, Bukit Raja – Rawang line agricultural pollution and Rawang to Who line near a cement plant 70kN, 80kN and 120kN insulators were tested after 20 years in service : electrical and mechanical integrity was confirmed on, including excellent performance in pollution tests (clean fog with actual naturally accumulated pollution).
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