Integral-Based Inertia Estimation Method for Power Systems with High Renewable Integration

The increasing integration of renewable energy sources in recent power systems has markedly altered the dynamics of system inertia. As a result, precise inertia estimation becomes essential for robust stability assessment and enhancing decision-making for grid operators. Traditional estimation methods, which primarily rely on the swing equation, frequently encounter numerical instabilities and inaccuracies, especially under conditions characterized by low or near-zero frequency derivatives. This paper proposes a novel inertia estimation method that employs an advanced integral-based formula to dynamically map and quantify inertia response across the grid. The proposed method functions independently of disturbance magnitudes and locations, and it achieves enhanced numerical stability while maintaining computational efficiency. Moreover, the integral approach employed in this method allows for a comprehensive capture of the inertia response, including both the inertia constant and the transient dynamics associated with inertia. Validation is performed on an IEEE 9-bus system that includes both traditional synchronous generators and non-traditional converter-based resources. The results reveal the superior accuracy and reliability of the proposed method, as it successfully identifies zones of weak inertia within the grid.