Improved Three-Phase Power Flow Method for Calculation of Power Losses in Unbalanced Radial Distribution Network

Recently, the need for improving the efficiency of distribution network in terms of power losses is being emphasised. A large share of total power losses refers to low-voltage networks which are usually unbalanced. For the power flow analysis, it is necessary to use three-phase modelling. This study presents modelling of distribution network elements and their implementation in backward/forward sweep (BFS) power flow method. An improvement of the BFS method is developed by using the breadth-first search method for network renumbering and creation of modified incidence matrix. The improved method minimises the read elements of each iteration and results in a significant reduction in total calculation time without accuracy loss. This improvement makes this method more suitable for using in real-time calculations. The proposed method is used for calculation of power losses in unbalanced and symmetrical network which are compared. The purpose of this test is to show the advantage of a three-phase power flow analysis compared with a symmetrical model.