Comparision of Dielectric Factors at Different Temperatures for New and Pre-Aged PILC Cables

Distribution system operators (DSO) are facing new challenges. They operate an increasingly mature network and, simultaneously, the grid utilisation is changing in the process of the energy transition. In order to be able to manage these challenges in the future, DSO use different instruments to operate the grid in a secure and cost-optimised way. One of these measures is the asset simulation in which the states of the networks can be described by applying basic parameters and ageing models, in order to determine the appropriate prioritisation of measures. However, in order to make these simulations even more significant, a project was initiated to investigate the ageing behaviour of paper insulated lead covered cables. In this experimental setup, cables are aged artificially and accelerated under defined conditions and their degeneration is closely monitored. This paper presents the first results of these investigations. The focus is on the measured values for the dissipation factor at a frequency of 0.1 Hz and 50 Hz as well as three different temperatures (10°C, 40°C, 70°C). Different groups of new and pre-aged cables of the type NKBA/NKBY are considered. The new cable test specimen shows hardly any dependencies with regard to temperature or frequency, whereas the pre-aged test specimens show clear differences in both temperature and frequency. This e.g. can be applied as one of the indications for the ageing of the insulation system.