Bernhard Heinrich - Weidman Transformerboard System AG Neue Jonastrass ۶۰ CH-۸۶۴۰ Rapperswil, Switzerland
Hans peter Gasser - Weidman Transformerboard System AG Neue Jonastrass ۶۰ CH-۸۶۴۰ Rapperswil, Switzerland
Christoph Krause - Weidman Transformerboard System AG Neue Jonastrass ۶۰ CH-۸۶۴۰ Rapperswil, Switzerland

In oil-cooled power transformers, a substantial part of the solid celluosic insulation consists of thick solid blocks, beams, rails and clamping rings or plates. Over the years, the use of laminated wood (plywood) products as an alternative to laminated pressboard has become popular, despite some difficulties these materials may entail. Comparing laboratory tests have been conducted in order to demonstrate the differences between the insulating materials, and this paper discusses the results from investigations of dielectric , mechanical behaviour was studied with partial discharge and breakdown measurements on different samples immersed in transformer oil. The aging .characteristics were investigated in extensive, long-term accelerated aging test series. It was found that due to the nature of manufacture, laminated wood properties are with regard to important features – as dielectric and mechanical strength, acids and sludge formation – noticeably inferior to laminated pressboard.

laminated , pressboard , wood , electrical , again