As a result of the significant increase in installations of generation plants powered by renewable sources and the simultaneous reduction in the use of conventional generation plants, the Regulatory Authority for Energy, Networks and Environment (ARERA) approved Resolution 300/2017/R/eel, which constitutes the first opening of the market for dispatching service to “electricity demand,” renewable generation units and storage systems. In this context, it is essential to develop control functions that also allow wind and photovoltaic systems to participate, in particular, in frequency regulation.

This report presents a review of inertial and frequency control methodologies, for wind and photovoltaic systems, taken from the scientific literature. The ultimate goal of the three-year research, as far as wind systems are concerned, is to develop a control strategy in order to provide further services to the grid in addition to those already developed for the same type of generation units integrated with storage systems. As concerns photovoltaic systems, the intention is to develop a control logic to enable this type of generation to provide upward frequency regulation service.

Among the control logics analyzed, some were selected for wind based on the current needs of the electricity system (focusing in particular on the need for much faster adjustments than traditional ones) and, for photovoltaics, those that also allow for the provision of fast adjustments (“ultra-fast” primary regulation and synthetic inertia) were considered most relevant. Finally, it should be noted that the ultimate goal of the activity, which will be developed in the following years, is to verify the control logics developed through both digital simulation and Hardware in the Loop (HIL).