Impact of MOV-Protected Thyristor Controlled Series Capacitor (TCSC) on Distance Relay Trip Boundaries in the Nigeria 330KV Power System

Metal-oxide-varistor (MOV) devices, connected in parallel have been used to protect the series compensation against overvoltage during faults. The MOV-protected series compensation increases the complexity of fault analysis and device protection. Hence the performance evaluation of distance protection scheme in the presence of Flexible Alternating Current Transmission Devices (FACTS) controllers which affect the apparent calculations at relay is very essential so as to develop a new setting for zones for distance relay on a transmission line. This work explores the effects of the installation of MOV and Thyristor Controlled Series Capacitor in the Nigeria 330kv transmission line distance relays under various fault conditions.