Subtransmission system reliability enhancement using a thyristor controlled series capacitor

This paper examines the impact of thyristor controlled series capacitors (TCSC) on distribution substation system reliability. In this application, the TCSC are employed in a system to adjust the transmission infeed impedances and, therefore, increase the transmission system capacity without increasing the system fault current levels. In this context, a reliability model of a multimodule TCSC has been developed and incorporated in the transmission system. Two kinds of performance indices designated as the delivery-point and system indices are presented to examine the impact of TCSC on the subtransmission system reliability. The results of the investigations show a significant improvement in the delivery point and system reliability when utilizing the TCSC. The technique is illustrated by application to several different subtransmission schemes.