Thermo-electrical ageing of 10kV paper insulated lead covered cables: experience from field experiments

The population of MVAC cables in the network of grid operators in the Netherlands predominantly comprises paper insulated lead covered (PILC) cables. This research presents the method and findings of an ongoing field experiment executed in the grid to assess the condition and ageing mechanisms of highly loaded PILC cables. The PILC cable degradation is analysed through in-field measurements and periodic material examinations, to address the key question: when will PILC cables fail due to thermal-electrical ageing under highly loaded operational conditions? Findings from the analysed cable systems show no noticeable additional cable degradation during the observed period. The primary mode of degradation is suspected to be the PILC compound. Depolymerisation measurements of the insulation paper indicate good material condition.