Fault Detection in Transmission Lines - A Novel Voltage-Based Scheme for Differential Protection

Current-based protection schemes such as distance, overcurrent, and differential relays are usually used to protect transmission lines (TL) in power systems where the high fault current plays a key role in detecting faults. The continuous development in the power network and emerging new technologies have made the power grid more complicated and soon will start to affect the reliability of the existing protection schemes. Issues like current transformer saturation, the effect of the mutual coupling impedance of the TL and emerging new power electronic-based technologies have become major challenges in power systems from a protection perspective. To avoid all the current-based problems this paper proposes a new voltage-based relay principle for TL protection to indicate fault occurrences in transmission networks. The proposed scheme is tested under all fault events to show that it is highly accurate when it comes to rapid trip activation during any of the tested cases.