A power flow method for radial and meshed distribution systems including distributed generation and step voltage regulator modeling

This paper proposes a new power flow method for radial and meshed distribution systems. The method convert a meshed distribution system with distributed generators into an equivalent single source radial distribution system, by breaking out the tie lines and distributed generators connections, and by abstracting auxiliary buses to the distribution network. The approach goes beyond the previous works by formulating a power flow algorithm considering the combined modeling of the distributed generators, voltage dependency of static loads, line charging capacitances, shunt capacitors and the step voltage regulator. In addition, the representation of the automatic voltage regulation at the buses where the distributed generators are connected, as well as the manual and automatic operational modes of the step voltage regulator, are also contemplated in the formulation. The proposed approach has been tested using several distribution networks providing good performance and promising results. Some of these results are presented on case studies for a 27-bus distribution network, in order to illustrate the applicability of the developed approach, as well as foster discussions about future works.