Abstract
Due to advancements in human society and lifestyle changes, the escalating demand for electric energy, along
with the expansion of industrialization, highlights the growing importance of green energy such as renewable
energy sources (RESs). Nevertheless, the combination of these sources introduces various operational and control
challenges for existing power systems. A pivotal concern in power systems involves achieving the essential load
frequency control (LFC) to mitigate the deviations in system frequency and unscheduled power exchanges among
control areas. This paper conducts a thorough review of the progression of LFC research, spanning historical,
present, and prospective power systems. The analysis encompasses considerations of traditional power system
models, the integration of RESs into traditional models, associated constraints, deregulated LFC, the application
of power electronics devices, energy storage implementations, and LFC strategies tailored for microgrids or
multi-microgrids. This comprehensive literature review aims to bridge the research gap by addressing contemporary
challenges, such as uncertainties in RES development, and provides insights into future directions for LFC
of the power systems.