Effect of Enhancing Distribution Grid Resilience on Low Voltage Cable Ageing

Enhancing system resiliency is getting more and more attention due to the climatic changes, growing number of earthquakes, floods and terrorist attacks. One pillar of system resiliency is distributed generation. As a result of distributed generation reverse power flow can occur causing the aggregate load in certain cases to surpass the rated capacity of the distribution cables without being detected. In this paper the effect of short term thermal ageing is investigated modeling the short term overloads. The samples were exposed to 4 cycle of 3 h thermal ageing at 110 degrees C and 125 degrees C and the changes of the insulation were followed by a mechanical (Shore D) and an electrical (loss factor) measurement method. The results suggest that the short term ageing processes have a measureable effect of the insulations and the calculated central frequencies are good indicators of the duration of the thermal ageing and the central loss factor values are decent indicators of the hardness of the insulation.