Load flow calculations on distribution networks by using a statistical approach

The availability of automatic informative systems containing all information on the networks as well as of the consumptions of the users and at the same time the knowledge of the typical load curves makes load flow calculations easier in statistical terms. This allows design of an enhanced calculation methodology to be used to check the compliance with the technical constraints in probabilistic terms. This is of paramount importance when considering distribution networks, particularly at the LV level, where, due to the reduced number of users connected to each feeder, the statistical effects could prove relevant for selecting the best size of network components. Although for MV networks real time feeder current measurements are generally available from SCADA systems, nevertheless it can prove very useful to have at disposal software tools allowing calculation of the values of currents, voltage drops and losses on each branch of the network. With better reason, this is important for LV networks, where, generally, automatic and systematic measurements are not available. The statistical method for load flow calculation in radial distribution systems described can be used both with reference to the present load condition (operation) and for the future load forecasted on the nodes of the network (planning studies). Although the validity of this approach is quite general, in this paper its applications for LV systems (three phases and neutral wire) is particularly emphasised.