Large-scale PV integration strategies in distribution grids

This paper studies large-scale integration strategies for photovoltaic (PV) energy sources in distribution grids, using storage technologies, grid extension and curtailment of PV power. A unified multi-stage AC optimal power flow problem is proposed for both the grid operation and strategy selection. The problem can be efficiently solved using standard power flow tools, selecting the optimal sizing and placement of storage components, distribution line upgrades and the degree of PV curtailment. The solution is parametric in the cost coefficients, thereby providing the grid operator a simple investment planning tool for different price estimates of storage components, distribution lines and imported electricity. A simulation example with a model and scenario of a large Swiss distribution grid illustrates the benefit of the method for the planning of future distribution grids with renewable energy sources.