Scale Change Approach to Assess Thermo-oxidative Degradation in NMN Insulating Paper

This paper presents the first step of a more global scale change approach, which aims to better understand the failure mechanisms during thermo-oxidative ageing by correlating a set of monitored parameters from a material (micro) to a system/assembly (macro) point of view. This multi-level approach requires modelling the failure mechanisms for individual sub-systems from a large electrical insulating system, such as rotating machines. The object studied in this work is a triplex structure of aramid-fibre paper/polyethylene terephthalate/aramid-fibre paper. AC breakdown of the triplex has been first modelled using a voltage divider principle and then compared with experimental measurements.