A comparison of PLL for online frequency tracking in power grids

Phase Locked Loops (PLL) are crucial for the implementation of frequency controllers in electricity distribution grids, especially since the integration of non-synchronous energy production and storage systems connected to the network by electronic power converters. PLLs are used to synchronize the injection of electrical signals from converters into the distribution grid. In this article, we present the five common PLL models suitable for transient stability analysis and perform a performance comparison for estimating frequency deviations. This comparison is based on the frequency estimation in IEEE 9-bus power systems and the evaluation focuses on accuracy and sensitivity to noise.