In many respects, the surge arrester business bears some interesting similarities to the bushings business. For one, like the bushing, an arrester is a comparatively inexpensive component - certainly in regard to the equipment it is connected to and intended to protect. Also, like the bushing, arresters serve two distinct markets – the power supply companies directly and various electrical equipment manufacturers, both of whom have somewhat different needs and expectations. And finally, arresters like bushings have traditionally relied heavily upon porcelain as a strategic component, yet both are now increasingly moving toward polymeric material alternatives (although at different rates).

However, in contrast to bushings where a number of different types and generations of technologies still co-exist in the marketplace, the large majority of arresters marketed today have undergone basically the same great transformation in technologies during the past twenty years. Due to the significant advantages offered by these developments, the older arrester technologies have for the most part been made virtually obsolete.

In particular, for MV arresters, there is now a comparatively high level of uniformity within the marketplace in terms of basic underlying technology, materials and overall appearance.

This does not mean to suggest that all distribution arresters perform the same or even that they all have the same product features. Actually, as these components have evolved toward a common platform technology based on metal oxide varistors and polymeric housings, a number of different designs and manufacturing processes have emerged. To a large extent, these have influenced the relative performance and cost of the various competitive offerings.

This two part feature article is intended to provide readers with a basic overview of the surge arrester business as it exists today and more specifically how it has evolved to its current level of technology. Part 1, in this issue, focuses on distribution line applications while Part 2, to be published in the Jan-Feb 2003 issue of INMR, will concentrate on station and transmission line applications.

Readers will find both good news and bad news in this article. The bad news is that – while totally objective and independent – the article will not aim to identify for them the ideal arrester for all special needs and applications. That will still require a detailed investigation on their part to optimally match product features and performance expectations of different arresters alternatives with the particular application requirements. But, there is good news as well. What this article will do is to help readers know what types of questions are important to ask potential arrester suppliers and hopefully to assist them to better evaluate the answers they receive.