The controllable impedance range of TCSC and its TCR reactance constraints

In this paper, the steady state characteristics of the thyristor controlled series capacitor (TCSC) is analyzed in time domain and frequency domain. Based on this, the controllable impedance range of the TCSC and its TCR reactance constraints are studied. It is shown that the key point to select the reactance of the TCR is to determine the ratio of the reactance of the series capacitor to that of the TCR. The concept of impedance sensitivity factor (ISF) of the TCSC is presented and it is proved that the ISF is the main factor determining the controllable impedance range of TCSC. The relationship between the reactance ratio of the series capacitor to the TCR, the ISF, and other operation performances of the TCSC are also studied.