ALT Data Fitting for Polypropylene-Based HVDC Cable Insulation Developed in the HEU-NEWGEN Project

This study aims at a preliminary validation of the electro-thermal cable life model developed in the HEU-NEWGEN research project by fitting the Inverse Power Model to Accelerated Life Test (ALT) data relevant to Polypropylene-based flat specimens tested under different voltages and temperatures. The goal is to know better how these materials behave over time under different steady electro-thermal stresses, which is crucial for developing more reliable HVDC cable systems. The results show a strong correlation between electric field and time-to-failure at each test temperature, although failure times are fairly scattered – as proved by the low value of the Weibull shape parameter. Life exponent values are found to be greater than 28, which is an indication of very good electrical endurance of the tested materials