The invention discloses a
grounding line selection method, a
grounding line selection device and an application
system based on an
active component of a zero sequence current. The
grounding line selection method and the grounding line selection device based on the
active component of the zero sequence current are used for a distribution network
system comprising a plurality of outgoing lines and a
bus for grounding line selection protection when single-phase grounding failure occurs. The grounding line
selection method comprises the steps of: zero sequence
current compensation for compensating measured value of the
active component of the aero sequence current of each outgoing line according to the distribution situation of the active component of the aero sequence current of the plurality of outgoing lines; line selection after the compensation, which is used for sequencing the
active components of the compensated zero sequence currents of the plurality of outgoing lines according to the amplitude size and selecting the outgoing line the zero sequence current of which has maximum active component amplitude; and line selection protection which is used for comparing the maximum active component amplitude of the outgoing line of the zero sequence current with the threshold value, judging that the
branch of the outgoing line is the grounding failure line if the maximum active component amplitude is more than the threshold value, otherwise, judging that the
branch of the outgoing line is the
bus grounding line if the maximum active component amplitude is less than the threshold value.