Load Flow Method for MV Unsymmetrical Unbalanced Distribution Networks Considering Distribution (MV/LV) Transformer Connection Type

Conventional well established load flow methods for transmission systems could not be utilized for distribution systems, due to their inherent characteristics. If methods such as Newton-Raphson and Fast-Decoupled are applied on distribution systems, the probability of their convergence would be low. Therefore, due to inherent characteristics of distribution systems, it is essential to develop the distribution version of load flow methods. MV Distribution networks usually have single source node and they have a radial configuration, supplying loads through distribution (MV/LV) transformers. Most of loads in public (or non-industrial) distribution networks are supplied in LV level. In the case of unbalanced loading, distribution transformer could decrease the load unbalancy by omitting the zero sequence current; therefore, distribution transformer windings connection type is an important factor in load flow solution and should be considered in load flow procedure. This paper presents a load flow method for unbalanced unsymmetrical MV distribution networks considering distribution transformer connection type.

Keywords:

Distribution networks , Load flow method , Distributiom transformer windings connection type , Unbalanced loading , Unsymmetrical network