Contribution to analysis of daily diagram of supply voltage in low voltage network: Working days versus non-working days

Supply voltage variations may have a significant impact on the service life and the operation of certain electrical equipments. Even relatively small deviations from the rated value can cause sub-optimal operation of equipment. The paper is focused on the voltage characteristics in low voltage systems, especially voltage variations, in order to characterize the point of consumption. A continuous long-term record of r.m.s value of supply voltage was realized. As a basis for analyzing of the voltage variations in low voltage network the comparative template of voltage for whole month, working days and non-working days was used. Selected statistics of the voltage record variations in the low voltage network were computed and the factor analysis was used to analyze the measured data. The results obtained from the experiments pointed to the fact that differences in daily diagram of supply voltage in working days and non-working days exists. These differences can be identified using the tools of statistical analysis on a monthly comparative template of voltage.