Assessment of frequency stability and required inertial support for power grids with high penetration of renewable energy sources

The increasing penetration of renewable energy sources (RESs) in the global power grid is transforming the traditional landscape of power generation. This shift from rotating synchronous generators to inverter-based RESs presents a unique challenge in maintaining the grid frequency stability due to the decline in system inertia. The stochastic nature of power generation, load demand, and grid inertia poses further challenge in ascertaining the frequency stability. This paper addresses this challenge by proposing indices that assess the sensitivity, resiliency, and permissibility of grid frequency under different RES penetration levels. These indices provide valuable insights into the stability of power grids and highlight the increased vulnerability of grid frequency to disturbances with increased RES integration. Monte Carlo simulation (MCS) is used to incorporate intermittencies and uncertainties associated with the load demand and RES generation. Furthermore, the paper presents a methodology to determine the required level of inertial support for maintaining the frequency reliability in the presence of RESs. The application of the proposed stability indices and methodology in a case study, which utilizes a modified IEEE 39-bus test system emulating a real-world power grid with diverse load types and RESs, validates their effectiveness. •Introduced indices for grid frequency stability in varying RES conditions.•Proposed a daily grid stability framework considering RES/load uncertainties.•Methodology presented to assess inertial support needs with RES integration.