STATCOM Analysis and Controller Design for Power System Voltage Regulation

In this paper, the mathematical model of STATCOM based on space vector theory is presented. The voltage equations are transformed into the synchronous rotating reference frame (dq-axis). The relationship between STATCOM parameters and stability, transient and steady state performances are determined. Stability investigation with Routh-Hurwitz criterion indicates that the STATCOM is a stable system and the numerical values of resistors, inductors and capacitors in the STATCOM equivalent circuit have no effect on stability. Steady state analysis reveals that the size of DC capacitor does not affect STATCOM steady state performance. The dynamic performances in terms of varying parameters are displayed in the forms of both root locus plot and Bode plot. The behavior of STATCOM for voltage regulation was simulated with ATP-EMTP. The case study was made on a 230 kV radial system. With simple PI controllers and modulus optimum design criterion, the voltage response to 3% step change of the reference showed approximately 5% overshoot and the settling time was within three cycles