Decentralized Controller Design for Static Synchronous Compensator Using Robust Quantitative Feedback Theory Method

The Static Synchronous Compensator (STATCOM) provides shunt compensation in similar way to the Static VAR Compensator (SVC) but utilizes a voltage source converter rather than capacitors and reactor. In practice systems use simple Proportional-Integral (PI) controllers for control of STATCOM. However, since the PI control parameters were usually tuned based on classical or trial-and-error approaches, they were incapable of obtaining good dynamic performance for a wide range of operation conditions and various loads in power system. For this problem, in this research a robust control approach based on the Quantitative Feedback Theory (QFT) method was proposed for the design of STATCOM controllers (AC-voltage regulator and DC-voltage regulator) and also supplementary damping controller for increase of power system oscillations damping is developed. A Single-Machine Infinite-Bus (SMIB) power system installed with a STATCOM with system parametric uncertainties were considered for case study. The system parametric uncertainties were obtained by changing parameters and load by 45% simultaneously from their typical values. To show effectiveness of QFT method, the proposed method is compared with a conventional method (classical P-I controller optimized by Genetic Algorithm (GA)). Several linear and non-linear time-domain simulation tests visibly show the validity of proposed method in compare with traditional method.