Harmonic State-Space Model of a Controlled TCR

This paper presents a harmonic state-space (HSS) model of a three-phase thyristor-controlled reactor (TCR) in a voltage-control application. In using the HSS description, the importance of incorporating the effect of harmonic interaction on the dynamics of a power system containing a TCR or other flexible ac transmission system controllers is illustrated. Although nonlinear in nature, the significant effect of switching instant variation is included in the linearized model. The model size is minimized with the selection of the minimum necessary set of harmonic frequencies. To validate the HSS models, the steady-state harmonics and the step response were validated with a PSCAD/EMTDC simulation.