The Effect of Unified Power Flow Controller and Ultra Capacitor in Hydro Power Plant’s Load Frequency Control

This paper first discusses the discrete implementation of Load Frequency Control (LFC) for hydropower plants using a Discrete Linear Quadratic Regulator (D-LQR). The impact of the sampling period on the performance of LFC with D-LQR is investigated. Then, the impact of the utilization of Flexible Alternating Current Transmission Systems (FACTS) solutions such as Unified Power Flow Controller (UPFC) and UPFC plus Ultra Capacitor (UC) on the performance of LFC is elaborated. The studies are performed on a two-zone hydropower plant. The studies show that increasing the sampling period can deteriorate the performance of LFC. Moreover, it is shown that utilizing both UPFC and UC can improve the response of LFC.