Impact of high penetration of variable renewable generation on frequency dynamics in the continental Europe interconnected system

This study addresses the development and operation of the European continental electricity system with a high penetration of wind and photovoltaic (PV) generation. The main focus of the work is the assessment of the impact of inertia reduction, due to wind and PV power electronics interface, on frequency stability indicators, as the rate of change of frequency and the frequency nadir following a large generation loss. The analysis is based on dynamic frequency stability studies, performed for every hour of the year and over a large number of weather scenarios. The outputs of these simulations are used to perform statistical analysis of these indicators and to estimate the critical instantaneous penetration rate of wind and PV, which the European continental synchronous area can accommodate from a system dynamics point of view. The results show that a single critical instantaneous penetration rate cannot be defined, since the frequency dynamic behaviour depends on parameters that change from one period to the following. Instead, this critical penetration rate should be calculated for every dispatch period. This study also highlights the growing importance of load self-regulating effect's contribution to frequency stability in the future system.