Uncertainty Propagation in Frequency, RoCoF, and Inertia Measurements

Maintaining power system stability is a critical objective for system operators. However, the increasing integration of renewable energy sources presents new challenges, especially due to the replacement of synchronous machines with static-conversion-based devices. This shift has led to reduced inertia, which is crucial during abnormal operations, and less predictable power generation. Inertia has become a key parameter in assessing the power system ability to handle power and frequency variations caused by disturbances or faults. Operators increasingly rely on this metric for implementing countermeasures. However, evaluating the accuracy of inertia estimates remains an unresolved issue. This chapter aims to show how to quantify the uncertainty associated with inertia, using its definition and identifying key sources of uncertainty. The Monte Carlo method is applied to simulate realistic scenarios, underscoring the importance of rigorous uncertainty analysis for critical parameters such as inertia.