FUZZY ADAPTIVE MODEL-REFERENCE APPROACH-BASED POWER-SYSTEM STATIC VARSTABILIZER

This paper presents a power system Static VAR stabilizer based on the fuzzy adaptive model reference approach. The Static VAR Compensator SV C (thyristor controlled reactor-fixed capacitor (TCRFC) type) is used for voltage regulation and to improve power system stability. The prop osed control system consists of a feedback fuzzy controller using the speed state deviation and its derivative as input signals. Moreover, a model reference with a fuzzy adaptive mechanism is built to make the power system speed deviation response follow a certain track. The refe rence model transfer function of second order is chosen which has desi red performance specifications. The input signal to reference model is the speed state deviation response. While the error between model ref erence output response and the power system speed deviation response i s an input signal to fuzzy adaptive mechanism, the other fuzzy adaptiv e mechanism signal is the derivative of the above mentioned error sign al. The control signal to the SVC stabilizer comprises the sum of the feedback fuzzy controller output and the fuzzy adaptive mechanism outp ut signals. The proposed control system is proved by digital simulatio n power system speed and torque angle states response due to various d isturbances. Furthermore, the effect of the additional signal comes fr om the fuzzy adaptive mechanism for enhancing the power system stabili ty. A comparison between power system response using the proposed SVC stabilizer and without adding the control signal of fuzzy adaptive mec hanism is presented. The results show the effectiveness and power of t he presented SVC. (C) 1998 Elsevier Science S.A. All rights reserved.