Method, device and system for monitoring electricity stealing behavior of power distribution network

According to the method, the device and the system for monitoring the electricity stealing behavior of the power distribution network provided by the invention, the second current values of the lines of the plurality of branch boxes connected with each line of the transformer side equipment of the power distribution network are obtained, and the sum of the second current values of the lines of the plurality of branch boxes connected with each line is calculated. Judging whether the first current value of each line of the transformer-side equipment of the power distribution network is equal to the sum of second current values of lines of a plurality of branch boxes connected with the transformer-side equipment of the power distribution network or not, and determining the line of which the first current value is not equal to the sum of the second current values in the plurality of lines of the transformer-side equipment of the power distribution network as a first abnormal line, the first abnormal line is the l