New Production Method Introduced at
ABB for Polymeric HV Arresters

Skytt. Polymeric HV arresters have been designed around the requirements of the new process.

“If you take a traditional design using porcelain,” says Torbjörn Skytt, “it is really not all that difficult to assemble a good quality HV arrester with zinc oxide elements. However, when talking about manufacturing such arresters with polymeric housings it is a completely different story - that is a much more difficult process. The arrester may appear good to the customer who at the beginning probably has a very hard time judging quality. But, ultimately it may end up performing quite poorly in service.”

Skytt is Project Manager for the range of polymeric HV arresters now being manufactured by ABB Switchgear in Sweden utilizing an entirely new production process. Skytt claims that these arresters now benefit from the increased robustness of this new process which apparently ensures consistent product quality across a range of tolerances normally encountered in manufacturing variables such as temperature and molding pressure.

“Critical suppliers have to become involved in the product development process from the very start.”

According to Skytt, the project to develop a new production technology for polymeric HV arresters actually began as far back as late 1995 at which time initial contacts were established with certain suppliers seen as crucial contributors towards designing an entirely new process. These included manufacturers of specialized molding equipment and tools as well as of the silicone rubber material used for HV applications.

Skytt explains that the intention originally was to start by choosing among the various potential suppliers and then proceeding next with process design. However he indicates that it was soon discovered that in order to achieve the best overall results all the various steps had to be performed simultaneously. “We soon found that a synergy among suppliers was required,” he says, “since everything ends up affecting everything else - it is really a ‘floating’ process.”

Schmid alongside computer control for new Desma molding equipment.

For example, the selection of the molding equipment supplier - Klöckner Desma, located in southern Germany - was made based largely on this philosophy. Says Skytt, “Desma was selected because they were the only supplier who talked to us from the very start about a fully-integrated product development process.

The same applies for our silicone supplier, Dow Corning.” Emphasizes R&D Manager, Bengt Johnnerfelt, “we have found that in situations such as this critical suppliers really have to be involved in the product development process from the very start. This is because there has to be a very close connection between process development and product development.”