Analysis of Low-Voltage Network Sensitivity to Voltage Variations Due to the Insulation Wear

Voltage variations that occur in the Low Voltage (LV) distribution networks are caused by different factors such as the load demand changes, intermittent powers of photovoltaic (PV) generation, the phenomena related to the operating environment of the network and their influence on the physical structure of the network, network faults, etc. The voltage variations can have important adverse impacts on the connected equipment. This paper aims to analyze the electrical conductance variation of the cable insulation, due to the degradation of the insulating material, and its impact on the nodal voltages. To this end, a probabilistic framework is proposed based on the Monte Carlo (MC) simulations and load flow calculations. The MC simulations are used here in order to characterize the insulation degradation of lines through scenarios and to model the resistance variation of lines. Considering the load demand and photovoltaic generation in a single-phase network as well as line the impedance data, in different degradation conditions, load flow calculations are conducted in order to calculate the nodal voltages. Simulation results reveal voltage drops over 50% depending on the position, number and degree of the cable insulation degradation as well as on the network working conditions. This result offers promising perspectives for the detection of cable degradations by use of Smart Meter (SM) voltage measurements.