Evolution of Load Frequency Control: From Classical Approaches to Intelligent & Resilient Frameworks

Abstract

Load Frequency Control (LFC) plays a vital role in keeping the frequency stable and maintaining the tie line power in interconnected power systems. With the addition of a large number of Renewable Energy Resources (RES), reduced system inertia, communication delay and cybersecurity issues, the conventional controllers fail to deliver optimal performance. This research presents a systematic and comprehensive review of various LFC methodologies from classical to intelligent control frameworks. This work provides a structured analysis based on quantitative and qualitative performance parameters, which include settling time, overshoot, robustness, scalability and computational complexity. An in-depth classification of various control techniques from conventional controllers to advanced controllers, which include model predictive control, robust control, AI-based controllers and optimisation methods, is presented. Further, the impact of emerging technologies, which include HVDC links, energy storage systems and decentralised architectures, on load frequency control is examined. The main challenges include cyber threats, high computational burden and lack of real-time validation. The study highlights that intelligent controllers and optimisation-based controllers offer superior performance, but the practical application is limited by complexity and stability concerns. Finally, future research is focused on real-time execution of LFC strategies for next-generation smart grids.