Transient Frequency Estimation Methods for the Fast Frequency Response in Converter Control

In an interconnected power system, frequency control and stability are of vital importance and indicators of system-wide active power balance. The shutdown of conventional power plants leads to faster frequency changes and a steeper frequency gradient due to reduced system inertia. For this reason, the importance of electrical frequency estimation methods is in- creasing, among others, as an input for the control of converter-based generation plants. The aim of this work is to implement, compare, and analyze the robustness of the Phase-Locked-Loop and Zero-Crossing, Gauss−Newton, and recursive Gauss−Newton methods in time-domain simulations in Matlab/Simulink. The parameters of these methods are tuned for different scenarios in a medium-voltage testbench. The sensitive parameters of the frequency estimation methods show a linear correlation to the magnitude of the active power imbalance so a simple implementation can be de-signed for simulations. With the linearized parameter calculation for the frequency estimation methods, the local frequency as an input for converter control is used for the fast frequency response of a full power converter, which counteracts frequency deviations in the power system. Finally, two different implementations of the fast frequency respons are compared. The Zero-Crossing Method shows the best robustness and the Phase-Locked Loop achieves the absolute best result