Simulation of the Effect of Combining LFC and AVR in a Thermal Power Plant with Reheat Turbine

In modern power systems, frequency regulation using Load Frequency Control (LFC) and voltage regulation using Automatic Voltage Regulator (AVR) play a crucial role in enhancing network stability against sudden load variations. This paper investigates the simultaneous integration of LFC and AVR in a single-area power system with a reheat thermal unit. The primary objective is to analyze the dynamic behavior of the system and evaluate the impact of coupling these two control loops on mitigating frequency and voltage fluctuations. An integral controller is employed in the LFC loop, while a Proportional-Integral (PI) controller is used in the AVR loop to enhance performance. The state-space dynamic model of the power system is derived, and simulations are conducted in MATLAB/Simulink. Simulation results demonstrate that the simultaneous integration of LFC and AVR significantly reduces frequency and voltage oscillation amplitudes while improving the system's settling time compared to the separate application of each controller. These findings highlight the substantial effect of the interaction between control loops in improving the dynamic performance of the power system.