Stability and harmonics in thyristor controlled reactors

Two methods for studying the interactions between an AC power system and thyristor-controlled reactors (TCR) are described. The first uses state variables to analyze the circuit containing the TCR. The resulting equations are linear differential equations with periodic coefficients. This formulation allows the study of stability, periodic operation, and resonance, which cannot be achieved by other methods. The second method uses a Fourier matrix description of the TCR. In this model the coupling between the different harmonics due to the switching is clearly shown.<>