The Practical Use of the DMM Model for Life Estimation of HVDC Cables Subjected to Qualification Load Cycles

A procedure for life and reliability estimation of full-size high-voltage direct current (HVDC) cables under the electrothermal transients caused by load cycles was successfully set up and applied to qualification load cycles prescribed by Cigre TB 496 and 852. However, a gap in the procedure is that only the phenomenological electrothermal IPM-Arrhenius life model was used so far, while no physical life model was ever employed. The estimation of phenomenological life model parameters requires accelerated life test data fitting without an in-depth understanding of aging processes. Physical life models are appealing as they take degradation due to local microdefects as the main source of aging, and their parameters in principle could be derived from short-term chemical-physical measurements on small dielectric specimens. This article fills this gap by using the physical Dissado-Mazzanti-Montanari (DMM) life model for life estimation of HVDC cables under the electrothermal transients involved by qualification test load cycles. The practical difficulties in using physical models in general, and the DMM in particular, are analyzed and assessed resorting to an application relevant to pre-qualification load cycles according to TB 852.