Analysis of diverse crosslinking compounds for HVDC cables concerning byproducts produced in the making

Abstract

The purpose of this degree thesis is to understand the structural and production difficulties of a high voltage cable operating with direct current. Furthermore, to have a look on different crosslinking compounds that are used when producing the cables with the base in existing patents from different companies. Three existing crosslinking compounds are compared with one crosslinking compound that are made at Åbo Akademi laboratory, a new compound in the field. The thesis is done incorporation with Maillefer Extrusion Oy.

This thesis will analyze the different crosslinkers’ behaviors and resulting properties of a sample made at a pilot machine at Maillefer Extrusion Oy, and compare the results in a way that would benefit the company with information and in the production of a cable that is more constructive for the industry.

Results show that the existing cable insulation recipes are better than the recipe with the new azo-compound made at Åbo Akademi. The degree of crosslinking gives a looser structure for the system compared with the existing insulations. Resistivity appears to be decreasing with higher voltages for the Åbo azo sample. The time it takes for Åbo azo sample to crosslink is longer than others and need slightly higher temperatures, which is also a problem. Then again, the new crosslinking compound from Åbo is an azo-compound, which in theory could give better by-products in the manufacturing process compared to peroxides that are used. One should also think about that the system with Åbo-azo is not optimized. The results are promising for the compound but should be further investigated.