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In this paper, a new single-ended travelling wave-based protection scheme for double-circuit lines is proposed. It is developed to operate in parallel with traditional phasor-based protective relays and is able to accelerate the tripping time in most fault scenarios. The proposed method considers the propagation of travelling waves in a loop formed by the faulted and healthy line circuits. Disturbances within a given protected zone can be reliably detected according to the amplitude, polarity and time difference between the arrival instants of travelling waves that reach the monitored terminal. Also, the accumulative cross-differential current deviation is used to confirm internal faults, distinguishing them from other non-fault events. From the analysis of massive digital fault simulations and actual field records, it is attested that the proposed protection is feasible and effective.