This article, from a paper presented at a past INMR WORLD CONGRESS by R.A. Bernstorf, then Principal Engineer, Insulators at Hubbell Power Systems (now retired) offered an overview of key considerations when it comes to loading and application of braced line post assemblies.

As service environments become cleaner, more wildlife and in particular birds return and play a proportionately greater role in what can adversely affect overhead networks. In particular, flashover outages attributed to birds, often included under the category of ‘unexplained outages’, have been a growing problem.

The advent of composite insulators began first in the U.S. and soon after in Germany and France. User acceptance was slow at the start and these products went through the ‘teething’ problems common to most innovations. Moreover, their initial pricing made them too costly for widespread application.

Application of RTV silicone coatings to porcelain and glass insulators in order to increase their pollution performance has been available for decades. Yet not everyone in the industry still appreciates how this coating technology operates and what factors will determine performance and effective service life.

Transmission lines the world over often have to traverse mountain ranges or plateaus situated at least 1000 m above sea level. In China, for example, it is estimated that some 60% of the country lies at this altitude or higher.

Building overhead lines and substations that perform reliably for decades has always been a challenge. Many things can go wrong over such a time frame, especially given increasing pollution, more weather extremes linked to climate change, growing interactions with humans and wildlife – all potentially culminating in problems linked to flashover, mechanical or other types of failure.