The value of AC optimal power flow models in the assessment of distribution grid electric vehicle and photovoltaic power plant hosting capacity – case study in Bosnia and Herzegovina

Electric vehicles (EVs) share is continuing its rapid growth. The share in total sales has more than tripled from the year 20 20 (4%) to 2022 (14%). Production from photovoltaic (PV) power plants in the year 2022 increased by 270 TWh, representing a 26% rise, reaching nearly 1300 TWh with the largest growth of all renewable technologies for the first time in history. In this paper, we assess the potential of installed power of EV charging stations (EV CS) and PV plants in real-world distribution grids. Hosting capacity (HC) calculation for both EV CS and PV plants is solved using two different approaches, one by using the AC Optimal Power Flow (AC OPF) formulation modelled in the Python programming language and the other solved iteratively with power flow simulation in DIgSILENT PowerFactory (DPF). To assess the benefits of the two approaches, we compare the solutions in terms of complexity and accuracy. AC OPF showed 3.3% higher results for EV HC and 21.6% higher for PV HC. Furthermore, the results detected weak points in the grid that can be used by the Distribution System Operator to identify transformers or lines that require replacement, to allow further electrification in the distribution grid.