Experiences of in field measured dissipation factor on MV PILC cables at 50 Hz

In the past several years, a significant amount of diagnostic data has been collected under known and adjustable test conditions, with the purpose of improving the diagnostic possibilities for medium voltage (MV) paper insulated lead covered (PILC) cables. Beside the complexity of the interpretation processes by itself, an additional challenge of onsite measurements is the investigation of mixed cable lines, as the analysis of the results is proven to be difficult. Moreover, when interpreting the measured values, i.e. diagnostic parameters, the problem often arises that different applied diagnostic criteria (e.g. in case of dissipation losses comparison of: absolute value, hysteresis, dependency on testing voltage) result in different statements. In this paper, empirically determined dependencies of the diagnostic parameter (in front of all the dissipation factor on test conditions) as well as the results of the in-field measured values and suggestion for their interpretation are presented.