Comprehensive study of a thyristor controlled series compensation model

More comprehensive mathematical equations of TCSC circuit for any period (including the whole transient process from firing the thyristors to a steady state) and for the steady state relating to the voltages and currents of the capacitor, inductor and thyristor components are precisely developed by using Laplace transformation. And the accurate mathematical relationship between the fundamental impedance of TCSC and the firing angle of the thyristors is further derived by using Fourier analysis. The validity of the mathematical analysis is demonstrated by using the electro-magnetic transient program (EMTP) digital simulations. Furthermore, a whole model system for TCSC dynamic simulation test including the actual microprocessor-based control hardware is constructed to compare with and verify the mathematical analysis and EMTP simulation. The test results agree well with the analytical and simulation results and clarify the validity of the assumption that the line current keeps sinusoidal, which is adopted in both the mathematical analysis and the EMTP digital simulations.