Active power distribution network differential protection method and system based on direct-axis current

The invention belongs to the technical field of active power distribution network fault section positioning, and provides an active power distribution network differential protection method and systembased on direct-axis current. The active power distribution network differential protection method based on the direct-axis current comprises the steps: acquiring three-phase currents at the two endsof a protected section; after it is detected that the protected section breaks down, calculating the direct-axis currents of all sampling points at the two ends of the protected section after breaking down respectively, and exchanging the information of all the sampling points at the two ends of the protected section; calculating the differential quantity and the braking quantity of correspondingsampling points at the two ends of the protected section, wherein the differential quantity is the absolute value of the sum of the direct-axis currents at the two ends of the protected section, andthe braking amount is the pr