Dealing with an overdose of photovoltaics at distribution level

Injection of large amounts of active power in the highly resistive distribution network by photovoltaic installations causes the voltage to rise along the feeder. This voltage rise is one of the major challenges the distribution network operator has to face. Rising voltage causes generators to trip with a loss of green energy at the most productive moments as a consequence. A technique known as Active Power Curtailment (APC), proposed by Tonkoski et al., is implemented on a part of a typical European distribution grid. The resulting energy yields are compared to the situation in which the inverter switches off. APC results in a serious decrease of production. Therefore, a modified version of APC, called APC-PI is proposed. By transforming APC from a proportional feedback controller to a PI controller, the total energy yield can be increased by as much as 40% in comparison to the production of APC controlled generators.