Design and Analysis of Optimal Based Control Strategy for D-STATCOM, Gaza Low Voltage Network - Case Study

Abstract

Power electronics and advanced control technologies have made it possible to solve power quality problems, which are certainly major concerning issues in the present era. System disturbances, voltage sags, swells and harmonics are few of severe power quality problems. This thesis focuses on the Distribution Static Compensator (D-STATCOM) device, which is widely used to overcome the power quality problems. The concept of this device is absorbing or generating controllable active and reactive power, which can be controlled to absorb/generate suitable amount of power by the device. Several control strategies have been in use for controlling D-STATCOM, such as: instantaneous reactive power control, direct/ indirect current control algorithm, symmetrical component method, and double-loop control strategy. These control strategies use different types of controllers, such as PI, Fuzzy, Pole placement and hybrid controllers. This thesis proposes a control strategy for D-STATCOM based on optimal control methods; LQR, and specially methods which are not applied before in D-STATCOM control, in order to utilize the benefits of the optimal control methods to reach optimum solutions for power quality problems, disturbance rejection in power systems and maximizing system robustness. This proposed control strategy depends on Dq transformation, Phase-Locked Loop (PLL) synchronization and constant DC link voltage. The optimal based control strategy will be designed and simulated for D-STATCOM to verify its effectiveness. The D-STATCOM device using the proposed optimal based control strategy provides fully voltage recovery, fully Total Harmonic Distortion (THD) elimination, maximum p.f and faster response, which making the optimal based control strategy for D-STATCOM an effective solution for power quality problems. The proposed control strategy will be designed, tested and analyzed on the demand of one of the low voltage (400V) networks of Gazacity as a case study.