Evaluation of methods for estimating distribution grid stress due to future installations of photovoltaic units

The rising number of photovoltaic (PV) units in distribution grids will necessitate significant investments in grid reinforcement. In research and practice, various methods are employed to estimate grid stress due to future installations of PV units. In this paper, the most common methods are presented and their accuracy is evaluated in a comparative case study. We find that methods assuming homogeneous plant sizes significantly underestimate grid stress. A probabilistic approach that assumes heterogeneous PV plant sizes provides considerably more accurate estimates.