An investigation on performance of XLPE compounds for high-voltage DC application

This paper presents the results of test procedures aiming at electrical characterization of polymeric materials for DC-insulation application. Electrical life tests at room temperature and space-charge observations were performed on specimens of two materials, i.e. a reference XLPE and a XLPE-based compound, in order to compare the behavior under both constant and periodically-inverted DC voltage. The compound differs from the base material due to the introduction of additives intended to modify conductivity, and thus space-charge trapping dynamics. The effect of additives is inferred coherently by both endurance estimation and space charge measurements, thus confirming that an increase of charge mobility can lead to an improvement of insulation performance in the presence of voltage inversion. The test procedures here discussed allow characterization to be achieved, and, thus, a feedback to be provided to insulating-material manufacturers, in reasonable times.