Voltage sag mitigation by means of thyristor controlled series capacitors

This paper describes the mechanism by which the thyristor controlled series capacitor (TCSC) is able to mitigate voltage sags. It also investigates and illustrates the use of TCSCs for mitigating voltage sags in both a radial power system and an interconnected one. This is possible due to the TCSC´s ability to limit fault currents by developing a high inductive impedance under fault conditions. This capability of limiting fault current is an additional feature presented by TCSCs, which may improve the quality of supply of power systems, in addition to others such as power flow control, power system stability enhancement, mitigation of subsynchronous resonance, etc