Design of robust UPFC controller using [H.sub.[infinity]]. control theory in electric power system

An industrial plant, such a power system, always contains parametric uncertainties. In the design of a controller the uncertainties have to be considered. Otherwise, if the real plant differs from the assumed plant model, a controller, designed based on classical controller design approaches, may not ensure the stability of the overall system. In this paper design of robust control for the UPFC controllers including power-flow and DC voltage regulator, using a [H.sub.[infinity]] loop-shaping design via a normalized coprime factorization approach, where loop-shape refers to magnitude of the loop transfer function L = GK as function of frequency is presented. As an example, we have designed a case for the system to compare the proposed method with a conventional method (classical P-I controller). AS the results of the linear and nonlinear simulations, the validity of the proposed method has been confirmed. Keywords: Unified Power Flow Controller (UPFC); Flexible AC Transmission Systems (FACTS); power system oscillation; [H.sub.[infinity]] loop-shaping
INTRODUCTION The Flexible AC Transmission Systems (FACTS) based on power electronics offer an opportunity to enhance controllability, stability, and power transfer capability of AC transmission systems . The Unified Power [...]