A Method for Correcting Frequency Estimates for Synthetic Inertia Control

Abstract

This paper presents three frequency estimation algorithms, one based on extended Kalman filtering, another on quadrature phase-locked loop and an adaptive notch filter. The paper proposes using some internal signals of these algorithms as an inverse reliability metric to determine the quality of the frequency estimate. The paper presents an algorithm to correct frequency estimates using these inverse reliability metrics. The algorithm is tested with signals with phase jumps and severe distortions. Accurate frequency estimates are of particular importance in real-time control applications. This paper shows the value of the proposed frequency correction algorithm in synthetic inertia (SI) control. It shows that for a test power system the corrector algorithm is critical in preventing the SI controller from erroneously injecting power that can exacerbate system faults.