Performance enhancement of modified SVC as a thyristor binary switched capacitor and reactor banks by using different adaptive controllers

Abstract

In this paper, a new topology with two shunts flexible AC transmission system (FACTs) devices, thyristor binary switched capacitors (TBSC), and thyristor binary switched reactors (TBSR) based SVC has been developed, which are working in parallel. Both TBSC and TBSR are designed, and simulation results are obtained for the dynamic loading condition. Switching of capacitor and reactor banks with thyristor as a switch is obtained at transient-free conditions so that the significant problem of switching harmonics is eliminated. The coarse control of reactive power is obtained by selecting switchable capacitor banks in binary mode. For fine control, the TBSR bank is designed with a total value equal to the lowest step value of the TBSC bank. It is discrete stepwise compensation at a period of one cycle, and this reactive power compensation is almost continuous as per requirement. It has near-to-zero switchings and zero steady-state harmonics. The mathematical model of TBSC + TBSR has been identified with the system identification toolbox. Different control strategies are implemented as PID controller, Model predictive control, and Model reference adaptive control. The proposed SVC topology performance is discussed based on the performance parameters such as rise time, settling time, and peak overshoot using adaptive controllers.