Method and device for judging type of small-current grounding system containing different-bus double-circuit line

The invention belongs to the field of electric power, and particularly relates to a method and device for judging the type of a small-current grounding system containing a different-bus double-circuit line, and the method comprises the steps: obtaining a zero-sequence voltage and a zero-sequence current, carrying out the out-of-limit starting of the zero-sequence voltage, and judging that the system is an actual grounding system if the amplitude of the bus steady-state zero-sequence voltage is greater than a voltage threshold value; comparing the polarity of the transient zero-sequence current at the outlet position of each line, and selecting a fault characteristic line; calculating the module value of the difference between the amplitude values of the zero-sequence current steady-state components of the adjacent detection points; and selecting a maximum value and a minimum value in the module values, comparing the maximum value and the minimum value with a current threshold value to judge the type of the sy