In this paper, a new algorithm based on harmonic signatures is proposed to detect extinction of secondary arc for single-pole auto-reclosing (SPAR). In the proposed algorithm, the TT-transform is used to highlight harmonics of healthy phase voltages. The criterion for the detection of extinction of secondary arc is harmonics amplitudes, which is calculated after the TT-transform. The algorithm is noncommunication and the threshold value is adaptive; therefore, for various transmission systems no special adjustment is needed. To evaluate the accuracy of the proposed scheme, numerous simulations under different conditions including fault location, fault inception angle and line compensation are performed, in all of which the highest reliability is achieved.

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