Grounding grid breakpoint diagnostic method based on transient electromagnetic abnormal ring principle

The invention discloses a grounding grid breakpoint diagnostic method based on a transient electromagnetic abnormal ring principle. The method comprises the steps of: according to a position to be detected, finding out one grid in the shape of a Chinese character 'tian' which covers the detected position; establishing a coordinate system in an effective detection area above the tian-shaped grid; placing a plurality of detecting lines in the effective detection area, and requiring the detecting lines to be symmetrical about the middle lines of the tian-shaped grid; determining coordinates of detecting points on each detecting line, and requiring consistency between the intervals of all the detecting points of the detecting lines and the positions of the detecting points; adopting a center loop device to coincide central points of emitting coils with receiving coils and the detecting points, carrying out measurement along one detecting line point by point, and obtaining measurement data; and drawing a secondary sensing voltage map of different detecting points of each detecting line at different sampling moments, and judging the positions breakpoints according to the rules of the breakpoints existing at different positions of the tian-shaped grounding grid. By adopting the method, the breakpoint diagnose can be directly carried out by means of the measured secondary sensing voltages under that condition that the normal operation of a power system is ensured.