Inertia sensitivity analysis of power grids with high penetration of renewable energy sources

The global power grid is undergoing a major transformation as a result of the growing utilization of renewable energy sources (RESs). The incorporation of these RESs is leading to a decline in the use of conventional synchronous generators and an increase in the use of inverter-based RESs. This shift is causing a decrease in the grid's inertia, presenting substantial difficulties for grid operators to maintain frequency stability. The purpose of this study is to examine the impact of declining inertia on the frequency behavior of the grid, as RESs become more prevalent. In order to measure the impact, this study utilizes eigenvalue analysis of power grids to assess the sensitivity of grid frequency and rate of change of frequency (RoCoF) characteristics, as well as the lowest frequency, to variations in grid inertia resulting from changes in RES penetration. Moreover, we have introduced indices that quantify the impact of RES penetration on the grid frequency behaviour in comparison to a grid without RES. To showcase the proposed approach, this research presents case studies using the modified IEEE 39 bus test system, which demonstrate the ability to assess the impact of a high RESs penetration on grid frequency characteristics.