Study on protection scheme using SFCL for transmission system with Thyristor Controlled Series Capacitor

• It is important to study fault characteristics of the transmission line with TCSC.
• The method to improve the protection system of a transmission system and a TCSC facility using SFCL has been proposed.
• The effect of fault current limitation and TCSC voltage reduction has been verified through PSCAD/EMTDC simulations.

In this paper, we propose a protection scheme using a superconducting fault current limiter (SFCL) for the power transmission system with Thyristor Controlled Series Capacitor (TCSC). TCSC can lead effectiveness such as power flow control, increase in transmission capacity, and improvement for system transient phenomena. But, because this has same effect to the reducing series impedances in transmission system, there are serious problem such as increase in fault current, transient stability deterioration and series voltage stress of TCSC in the transmission line. The proposed protection scheme using the SFCL into TCSC configuration can mitigate these problems. In addition, SFCL can be expected to protect the TCSC from a large transient current generated by lightning or switching surge in power transmission system. To verify the effect of the proposed protection scheme, PSCAD/EMTDC is used. From simulation result, we had good results for fault current limitation and insulating protection of TCSC.