Enhancing Frequency Stability in Power Systems Using Adaptive Droop-Controlled Battery Energy Storage System

Frequency stability in power systems is increasingly challenged by sudden generation-load imbalances. This paper proposes a novel Hybrid Droop-Adaptive Control strategy with Lead-Lag Washout (LLW) compensation for Battery Energy Storage Systems (BESS) to enhance frequency regulation during load disturbances. The control approach incorporates adaptive tuning of the droop gain, dynamic deadband adjustments, and LLW compensation based on real-time measurements of frequency deviation and Rate-of-Change-of-Frequency (RoCoF). The proposed controller was implemented and validated through dynamic simulations on the standard IEEE 14-bus test system using DigSILENT PowerFactory 2024. The study includes calculation of optimal BESS power and capacity requirements for worst-case load scenarios. Simulation results under different load disturbances including a 20% sudden load increase and an abrupt bulk load disconnection demonstrate the superiority of the proposed BESS control strategy in improving frequency nadir, reducing stress and ramping demands on synchronous generators, and better preserving spinning reserves. This indicates that our strategy significantly enhances frequency stability during load perturbations. Furthermore, it highlights that BESS effectiveness is contingent upon optimal sizing, making this a critical consideration for planning frequency support systems in modern power networks.