A New Direction Relay Algorithm of Three-Phase Short-Circuit for The DFIG-Based Wind Farm Outgoing Transmission Line

The transient characteristics of the DFIG-based wind farm transmission line with a capacity of low-voltage ride-through (LVRT) is analyzed in the paper. When a three-phase short-circuit occurs at the DFIG-based wind farm outgoing transmission line, the conventional direction element based on power frequency algorithm can trip correctly if the fault current through the distance relay is provided by the power system, otherwise, it will not be able to get accurate and stable judgments about the fault direction if the fault current through the distance relay is provided by DFIG. A new direction relay algorithm for the DFIG-based wind farm outgoing transmission line is proposed. The fault direction can be judged according to the fluctuation range of the phase calculated by the traditional phase-to-phase distance relay using positive sequence polarizing voltage within a certain time after a failure. The simulation results show that the new direction relay at both sides can both provide accurate fault directions no matter what position the three-phase fault occurs on the outgoing transmission line.