Single‐ended travelling wave protection algorithm based on full waveform in the time and frequency domains

Abstract

Single-ended travelling-wave-based protection has been available for several years, providing the advantages of low cost and no requirement for communication and synchronisation with the remote end. However, conventional single-ended travelling-wave-based protection has low reliability due to its use of only partial fault information, and it has high dependence on extracting a second reflected wavefront. A new single-ended travelling-wave-based protection algorithm using the 2 ms full-waveform post-fault signal in the time–frequency domain, which avoids the discrimination of the reflected wavefront, is presented. First, the full-waveform representation of the travelling wave in 3D subspace is proposed. The fault characteristics of the wideband travelling wave are analysed at different scales. Second, for faults that occur within one line or on adjacent lines, the propagation characteristics and reflection and refraction process are analysed in detail. Then, the correlation and difference of the full waveform are presented qualitatively and quantitatively. Finally, a time–frequency spectrum matrix is established based on the full waveform, and the protection algorithm is developed by using a time–frequency spectrum matrix and wave matching technology. Extensive simulations under different conditions verify the wide applicability and high reliability of the proposed algorithm.