Analysis of TCSC fundamental-frequency impedance characteristic considering thyristor conduction property

The PSCAD/EMTDC digital electromagnetic transient simulation shows that, the fundamental frequency impedance characteristic curve of TCSC(Thyristor Controlled Series Capacitor) varies along with the line current in line current synchronization mode, which induces obvious deviation of open-loop impedance control in the hierarchical TCSC control system. A TCSC fundamental-frequency impedance model considering the variation of thyristor conduction characteristic in line current synchronization mode is built to theoretically analyze its mechanism and the digital simulation shows the LSM(Least Square Method) applied in the open-loop impedance control has large table look-up error. Two table look-up approaches, i.e. three-point quadratic interpolation method and linear interpolation method, are proposed and their effectiveness and reliability are validated by dynamic simulative experiments.