Using current traveling waves to implement directional elements in parallel lines

A traveling wave-based directional element based on only current signals for parallel transmission lines is presented in this paper. With the current waveform samples captured in one-terminal of both parallel circuits, the direction of the first fault-induced traveling waves is identified. Therefore, by using two directional elements, one at each transmission line end, and applying a permissive overreaching transfer trip scheme through a communication channel in conjunction with an appropriate overcurrent supervision, it is possible to classify faults as internal or external from the monitored transmission line, without the need to analyze voltage traveling waves. This classification (internal and external) and fault direction identification (forward or reverse) can improve the performance of other protection schemes and accelerate the trip decision without compromising the protection security and reliability.