Analyzing Rotational Inertia, Grid Topology and their Role for Power System Stability

Large-scale deployment of Renewable Energy Sources (RES) has led to significant generation shares of variable RES in power systems worldwide. RES units, notably inverter-connected wind turbines and photovoltaics (PV) units that do not provide rotational inertia, are effectively displacing conventional generators and their rotating machinery. This has implications for frequency dynamics and power system operation: Since frequency dynamics are faster in power systems with low rotational inertia, this can lead to large transient frequency and power oscillations in multi-area power systems. Grid topology also has a key role for frequency dynamics as meshed grids are more resilient to disturbances than non-meshed grids.This paper investigates the role of low rotational inertia and different grid topology setups on power system stability for a three-area power system. The presented contributions, both analytical and simulation-based insights, extend previous results for a two-area power system.