Assessing the photovoltaic (PV) hosting capacity of distribution grids

Overcoming local limitations in distribution grids with high photovoltaic (PV) penetration may be a challenging issue with non-optimal costs if appropriate planning strategies and regulations are not utilized. The installation of PV systems should be done according to local grid capability in order to avoid costly reinforcements. Careful consideration of the PV hosting capacity limits can help significantly in maintaining the secure and healthy operation of the electricity grid and can help avoid damages caused by violating thermal limits or by exceeding the voltage limits set by EN 50160 during times of high PV power production. In this paper, the methodology and approach followed to define the maximum PV capacity of a typical urban distribution grid is presented and analysed. The application of alternative measures at distribution grid level such as the local voltage support via reactive power regulation is investigated in finding optimal operating conditions for increasing PV capacity. It has been demonstrated that the urban distribution grid under consideration can accommodate a PV hosting capacity that is comparable to the firm capacity (the allowed operating capacity of the substation by adapting the requirement of the Grid Rules for one contingency) of the transmission substation.