Impact of fast primary regulation and synthetic inertia on grid frequency control

This paper is a preliminary study, based on control theory tools, of the impact of new grid frequency regulation services on power system dynamic behaviour. In particular, fast primary frequency control and synthetic inertia are considered. The first objective is to assess whether, for high penetration levels of these two new regulations, system asymptotic stability is lost; the second is to study the sensitivity of performance indicators of frequency dynamics, such as the steady-state frequency deviation, the initial Rate Of Change Of Frequency (ROCOF), the maximum frequency deviation and the time of its occurrence, in the presence of large disturbances. The analysis is performed considering a single bus-bar model, first of a fictitious test system and then of the Sardinian power system. It is shown that the fast primary control has a predominant role to determine the maximum frequency deviation, while synthetic inertia mainly affects the initial ROCOF and the time of the maximum frequency error after the perturbation.