Distance protection for six-phase transmission lines based on fault induced high frequency transients and wavelets

Six-phase transmission is an optimal solution for increasing the power transmission capability of overhead power transmission lines over existing rights-of-way. This new technology, however, causes some protection problems. This paper introduces a new technique based on wavelet transform for high-speed distance protection of six-phase transmission lines. The technique utilizes a wavelet to capture the fault induced high frequency transient currents superimposed on the power frequency modal currents. The trip decision is based on the relative arrival times of these high frequency signals at the relaying point. The introduced technique is tested and validated through simulation studies. The results show that the technique is accurate and high-speed in fault detection irrespective of the fault type, fault inception angle, and fault resistance. Moreover, it is insensitive to the line terminals and transposition.