In order to better predict the future of composite insulators one of the factors that has to be taken into consideration is alternative technologies, i.e. porcelain and glass insulators. Over the past two decades, composite insulators have captured a large market share away from these insulators yet they still manage to retain considerable market shares of their own. Intense competition between composite insulators and porcelain/glass insulators will clearly continue over coming years go so it is useful to examine how this may evolve as a predictor of the future of composite insulator technology. Comparison of these alternative insulator technologies should ideally be considered from three different perspectives: price, performance and maintenance.

Relative prices in China for these different types of insulators in the range 110 kV to 1000 kV AC and ±500 kV to ±800 kV DC are shown in Figs. 5a and 5b, respectively. Price per string is calculated based on typical service environments and it can be seen that SR composite insulators are always less costly than porcelain or glass insulators. Moreover, this price advantage grows with higher voltage or mechanical level and is also much greater in DC.

In regard to performance, there are four main categories that should be taken into account when selecting insulators: pollution, electrical, mechanical and long-term service. The current situation is that when it comes to resisting pollution, composite insulators are much better than either porcelain or glass. Insofar as electrical performance, composite insulators are considered about equal to porcelain or glass, while for mechanical performance, composite insulators are seen as equal or somewhat worse. When it comes to long-term performance, porcelain and glass insulators are both ranked better than composite types. For maintenance, it is well accepted in China that composite insulators are far superior to porcelain or glass since.

Of course, when utilities decide on insulator technology, the relative importance of each of these performance aspects will differ, usually based on the service environment where they are to be applied. All these factors are therefore taken into consideration before a final decision is made.

Composite insulators remain the preferred choice in China due to lower price, superior pollution performance and less need for maintenance.

In the case of China, the most important of these different variables is price with the relative weights given for price, performance and maintenance being about 45%, 30% and 25% respectively. Given this, composite insulators emerge as the preferred choice due to lower price, superior pollution performance and less need for periodic maintenance.