There is a common problem of three-phase imbalance in China's low-voltage distribution network

and evaluating the additional losses caused by three-phase imbalance is an urgent issue that power supply companies need to address. However

the current estimation of regional unbalanced losses mostly focuses on neutral line losses and does not evaluate the additional phase line losses caused by imbalances. Moreover

achieving the evaluation of unbalanced additional losses in all stations in the region still faces the problem of difficulty in obtaining temporal data for all stations. Therefore

based on the relationship between current phasor and sequence component

the derivation of unbalanced additional losses (including neutral line additional losses and phase line additional losses

i.e. losses caused by zero sequence and negative sequence currents) was first achieved; Then

based on the types of low-voltage distribution network substations in China

some typical substations were selected to obtain time-series phase current data as sample substations; After analyzing and completing the time-series data of the sample station area

clustering is performed based on the current characteristics of the station area to obtain several typical clustering clusters; Secondly

the remaining substation areas (with only monthly average phase current data) are matched with clustering clusters through a classification model. Finally

evaluate the range of the total additional losses caused by imbalance and the additional losses caused by unbalanced phase lines

and apply the Chebyshev inequality to narrow down the estimation range and improve confidence; And through actual data verification

more than 85% of the upper regions were classified into the correct cluster

and the confidence level of the final evaluation of the unbalanced additional loss range reached 89%.