The invention provides a
transformer excitation
inrush current and fault differential current recognition method based on a
Hausdorff distance algorithm. The
transformer excitation
inrush current and fault differential current recognition method comprises the steps of: acquiring secondary currents of current transformers at two
differential protection sides of a
transformer on each cyclic wave N point, and form a differential current
signal sequence I; judging whether a value of the differential current
signal sequence I exceeds a setting valve of a
differential protection starting component, and starting a criterion disclosed by the invention for distinguishing a fault differential current and an excitation
inrush current if the value exceeds the setting value
differential protection starting component; judging and acquiring an extreme value of the differential current
signal sequence I by adopting a 1 / 4 cyclic wave data window, regarding a differential sequence A after per-unit treatment as an edge feature point of a
Hausdorff distance algorithm object graph, regarding a standard sine sequence B with amplitude being 1 as an edge feature point of a
Hausdorff distance algorithm template graph, comparing an Hi value with a set Hausdorff
distance threshold value Hset, and conducting protection action if the Hi value is less than the threshold value; and blocking protection if the Hi value is greater than the threshold value. The transformer excitation inrush current and fault differential current recognition method is used for directly judging difference of waveform pattern overall features of inrush currents including symmetric inrush currents, and ensures correct action of transformer differential protection.