Impact of the nominal and real peak power of PV systems on grid reinforcement

The rising number of photovoltaic (PV) units in distribution grids will necessitate significant investments in grid reinforcements. The industry-standard in grid planning is to use the rated power of the PV systems to estimate grid stress. However, in this paper, we show based on an empirical analysis of real-world data that the maximum feed-in of PV units is lower than their rated power. Consequently, grid stress and necessary grid reinforcement investments are overestimated. In order to quantify this effect, we run a comparative case study based on three representative distribution grids and a varying degree of PV penetration. Results show that on average the industry-standard approach overestimates the necessity of reinforcements in up to 3 % of the cases compared to the approach with adjusted PV feed-in. The magnitude of the effect depends on individual grid characteristics and is stronger at higher PV penetration levels. Furthermore, adjusting PV feed-in also affects suitable technologies for grid reinforcement. Since grid stress is lower, we show that the potential applicability of smart technologies (on-load tap-changers and reactive power control) increases, whereas the necessity of conventional reinforcements decreases.