Distributed Computing is growing up in interest in many applied fields of scientific research. Power system operation is becoming increasingly complex due to the Distributed Energy Resources (DERs) integration at various voltage levels. In this context, the need to automate grid operation is ever fundamental in order to ensure adequate levels of reliability, flexibility and cost effectiveness of power systems. This report shall be intended as a support for the understanding of methodological aspects and principles for the solution of power flow equations through a distributed approach, in a context where multiple interacting entities share a portion of their grids and want to align their computation in an automated way. The aim is both to give the reader a comprehensive overview of the software used for the implementation, the Portable Scientific Extensible Toolkit for Scientific Computation - PETSc, and the principles followed to build the Distributed Power Flow Solver as well as the specific features that make it different from other distributed solvers available in the literature. Additionally, two frameworks are presented as potential applications for the model. The European transmission networks level, in the context of capacity calculation, and the transmission-distribution networks coupling. In the beginning a short literature review on both frameworks is presented.