EPR power cables rated 105°C/140°C

A cable insulation system based on EPR insulation and EPR-based semiconductive layers was introduced over 25 years ago. The possibility of raising the rating of this system was evaluated. The results show it is completely justifiable to rate the EPR system at 105°C for continuous and 140°C for emergency service. Thermal-oxidative aging data are analyzed, and a comparison with older insulations is given. The behavior of power factor and the AC dielectric strength of cable made with this EPR through multiple cycles and after continuous exposure to the elevated temperatures were measured. Comparisons of the resulting data with measurements made at the current 90°C/130°C temperatures are given. The insulation´s physical properties after exposure to the proposed higher temperature and the screen resistivities after cyclic and continuous exposure to current and proposed temperatures were measured. Deformation of the EPR versus temperature and measurement of impulse strength after temperature exposures are discussed. Examples of ampacity increases available, suitability of jacketing materials, and moisture resistance of the EPR system are described