PHASOR DYNAMICS OF THYRISTOR-CONTROLLED SERIES CAPACITOR SYSTEMS

This paper develops simple but accurate continuous-time, large-signal dynamic models for a Thyristor-Controlled Series Capacitor (TCSC). The models are based on the representation of voltages and currents as ti me-varying Fourier series, and focus on the dynamics of the short-term Fourier coefficients. Truncating the series to keep only the fundamen tal components provides a natural dynamic generalization of the famili ar quasi-static phasor representation. Systematic simplifications or r efinements of our fundamental phasor dynamics model yield a variety of other models. We establish that even the simplest of these models pre dicts the dynamic behavior of the TCSC very accurately. Our phasor mod els provide a powerful basis for simulation, more than an order of mag nitude faster than detailed time-domain circuit simulation. The phasor models present an attractive alternative to sampled-data models, havi ng the advantages of simpler representation, modularity, and direct co mpatibility with the phasor models that are routinely used to represen t the dynamics of generators and other power system components.