A distance protection scheme based on fast phasor extraction algorithm

In view of inherent defects in Fourier algorithm and least square algorithm, which are widely applied in traditional distance protection, a novel fast phasor extraction algorithm is proposed. Based on the principle of least square matrix pencil, the order of compensation matrix is reduced, thus the calculation amount is decreased and the calculation efficiency is improved. Firstly, the power frequency phasors are extracted by the proposed fast phasor extraction algorithm; secondly, based on RL model of transmission line and power frequency fault location equation is utilized to judge whether the fault position is inside or outside the protection zone. In the proposed distance protection scheme, only single end electric quantities are utilized, thus the sensitivity of the protection is obviously improved. Results of both theoretical analysis and simulation show that the proposed distance protection scheme possesses such advantages as small calculation amount, high accuracy, slightly affected by data window and so on, therefore it is practicable.