  Challenges in the planning and operation of distribution networks caused by
the integration of distributed energy resources (DERs) create the need for the
development of tools that can be easily used by system operators, industry, and
the research society but are also easily upgraded with new functionalities. The
full implementation of one such open source tool, named pp OPF (pandapower
Optimal Power Flow), is presented in this paper. Pp OPF is the tool used for
three-phase optimal power flow (OPF) calculations and it is based on already
existing functionalities of pandapower, a Python library for power system
calculations. The developed tool enables the possibility to use both
power-voltage and current-voltage formulation in different OPF problems, such
as determining the photovoltaics (PVs) hosting capacity in three-phase
distribution networks, the problem on which the functionality of the developed
tool is tested. Additionally, the accuracy of pp OPF is verified by comparing
the results with ones obtained by pandapower power flow calculation for the
same set of input values. The open-source implementation allows further
upgrades, the addition of new functionalities, and the creation of new case
studies relevant to the planning and operation of distribution networks.
