A novel instantaneous value based incremental quantities distance protection for AC transmission lines

Conventional distance protection elements are predominantly based on voltage and current phasors. As a result, those elements require the half-cycle/full-cycle time window to estimate the accurate voltage and current phasors. Using information in the transients of voltages and currents is a possible way to improve the distance protection operation speed. To break free of phasor limitations, this paper presents a novel incremental quantities distance protection algorithm based on instantaneous values of voltage and current. Firstly, the instantaneous voltage distribution along the AC transmission line is analysed. Then, the principle of the incremental quantities distance protection is presented. The influence of fault angle on the presented algorithm is also analysed and a solution is proposed to deal with the relative small fault angle conditions. Finally, an extensive simulation results based on PSCAD/EMTDC simulation verify the performance of the presented incremental quantities distance protection.