Method and system for testing sheath impedance of high-voltage cable cross interconnection system

The invention discloses a method for testing the impedance of a sheath of a high-voltage cable cross interconnection system. Three-phase current data and three-phase grounding circulating current data of the head and tail sections of cable bodies of the cross interconnection unit and three-phase current data, three-phase grounding circulating current data and three-phase induced voltage data of the cable body at the cross interconnection box are detected and collected, so that the three-phase sheath impedance of the three sections of cables is directly calculated; whether the three-phase sheath impedance is abnormal or not is judged, so that whether the detected cross interconnection unit has defects or not can be judged; the method is simple to operate and accurate in detection result, and live detection can be realized without an external excitation source; according to the invention, the cross interconnection unit is detected in real time, and the sheath impedance of the three sections of cables of the cro