The Effect of Transformer Representation on the Convergence of the Backward Forward Sweep Method for Distribution Power Network

The small impedance branch has a great significant effect on the convergence of the power flow methods. Whether the power flow converges or not when it used for systems with small impedance branches not only depends on the power flow methods but also the representation of the network elements. The backward forward sweep (BFS) method which is widely used for distribution networks is discussed in the paper. When the BFS method is applied to systems with small impedance transformer branches, the divergence of power flow may occur. The transformer representation affects the convergence property of the BFS method greatly. The Pi equivalent circuit usually causes the divergence of the BFS method, while the standard equivalent circuit with an ideal transformer does not. The results of an experimental system validate our conclusion.