Reinforcement Learning-Based Unified Power Flow Controller for Stability Enhancement in Hybrid Renewable Energy Systems: A Comprehensive Review
Keywords:
Hybrid Renewable Energy Systems (HRES), Reinforcement Learning (RL), Unified Power Flow Controller (UPFC), Flexible AC Transmission System (FACTS), Power System Stability, Renewable Energy Integration.Abstract
The fast integration of renewable energy sources into today power systems has made quite a few issues around voltage stability, frequency regulation reactive power control,and just overall grid dependability. Hybrid Renewable Energy Systems, maybe HRES , and especially ones that match wind energy conversion systems with diesel generators, have appeared like a solid option for keeping power coming in a continuous, and sustainable way. Yet the breaky, intermittent nature of renewables causes operational uncertainties that need advanced control methods. Flexible AC Transmission System devices, commonly called FACTS, especially the Unified Power Flow Controller, or UPFC, have shown notable promise for better power quality, steadier voltage, and improved power flow steering. Lately, Reinforcement Learning, RL, has drawn a lot of interest as an intelligent control approach that can adjust to shifting operating situations without needing perfect mathematical models of the system. This review aims to gather and discuss what has recently happened in renewable energy integration, ways to strengthen power system stability, FACTS controller applications, and RL based control approaches. It also looks closely at the existing work on voltage stability evaluation, transient stability enhancement, demand response optimization, energy management, and more intelligent UPFC control. In addition, the benefits, constraints, and open research gaps tied to traditional techniques versus AI based control are covered. In the end, the review points out that merging RL with UPFC looks promising for adaptive power flow control, reactive power compensation, and stability improvements within power systems that include renewables. Future research directions are also brought forward, so smart grid infrastructures can become more intelligent, resilient, and sustainable as renewable penetration keeps increasing.
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