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 time-varying Fourier series, and focus on the dynamics of the short-term Fourier coefficients. Truncating the series to keep only the fundamental components provides a natural dynamic generalization of the familiar quasi-static phasor representation. Systematic simplifications or refinements of their fundamental phasor dynamics model yield a variety of other models. The authors establish that even the simplest of these models predicts the dynamic behavior of the TCSC very accurately. Their phasor models provide a powerful basis for simulation, more than an order of magnitude faster than detailed time-domain circuit simulation. The phasor models present an attractive alternative to sampled-data models, having the advantages of simpler representation, modularity and direct compatibility with the phasor models that are routinely used to represent the dynamics of generators and other power system components.