INTRODUCTION
In 2005 an article about toughened glass insulators (TGI) titled “Return to Clarity” was published. Fifteen years later, this sequel article by a team including the two original authors, picks up where the former concluded with optimism about the future of TGI technology in the USA. Thanks to the deeper understanding of TGI, we are witnessing today a new age of toughened glass insulators. The built-in characteristics of Sediver TGI’s provide safety, reliability and resilience, which yield measurable cost savings. This sequel article will further explore these attributes which are being recognized by a growing number of line crews and asset managers responsible for maintaining their HV lines.

HISTORICAL OVERVIEW
TGI technology was first introduced by Sediver in Europe in the early 1950s, and found its way to North America in the 1960s. With the advent of polymer technology in the 1970s, attention quickly turned to its promise for a swift evolution towards an ideal insulator that was no longer a string of modular units, but a single light-weight unit, virtually indestructible, vandalism proof and possessing unequalled pollution performance. True to its tradition of pioneering and innovation, Sediver also became an industry leader in polymer technology and a major USA producer until 2001. By that time, the USA was the largest polymer market in the world and TGI almost vanished from use across the country. In 2003, EPRI published a comprehensive review of the first 25 years of the polymer in-service experience. Updated again in 2012, it identified many utilities reporting unacceptable numbers of polymer failures while expressing concerns for their long-term reliability. The emerging doubts about the ability of polymer technology to fulfill its early promises invigorated Sediver to re-introduce toughened glass to the USA for HV line suspension applications. Today, utilities across the USA are using TG insulators on a regular basis. The trend has attracted several new suppliers of glass insulators to the US market, while allowing Sediver to justify the investment in a new US-based factory and state-of- the-art test lab in West Memphis, Arkansas.

Read full article in the Linemen Safety Special Edition 2020