Investigation of Structural Dependence of Cyclical Thermal Ageing of Low Voltage PVC Insulated Cables

Abstract

The widespread use of renewable energy sources has considerably expanded distributed generation. An unbalanced load on distribution cables may also result from the recent increase in novel appliances and electric vehicles, the reverse power flow may create short-term overloads. These transient overloads increase the temperature for a short time beyond the limit, which causes degradation. However, the temperature distribution on the cable is not even. Therefore, the cable components are not degraded evenly and similarly. This publication describes the change in electrical properties of low-voltage cables caused by short-term cyclic artificial ageing to track the impact of these brief temperature rises. This study examines how cable structure affects the dielectric characteristics of cable specimens. Four cable samples, each measuring 50 cm in length (SZAMKAM 0.6/1 kV 16 mm2× 4 manufactured by Prysmian MKM Kft, Hungary) put through an accelerated ageing test in a temperature-controlled oven after changing their structures by removing their layers. Three rounds, each of six hours, accelerated thermal ageing were applied. After each round of ageing, the dielectric parameter tanδ and capacitance were measured by Dirana Dielectric Response Analyzer in the laboratory at room temperature 24±0.5∘C. Furthermore, the polarization and depolarization currents were also studied. The results show that changing the cable structure impacts the dielectric parameters, especially the effect of belting layer is significant. From point of view of aging the PVC belting layer protects the diffusion of plasticizers of inner structure.