Abstract: In order to timely discover the faults in the high-voltage cable cross-interconnected grounding system, this paper constructs a new criterion based on the ground currents at both ends of the metal sheath of cable to classify and locate the faults of power cables. Firstly, the amplitude and phase of grounding current of metal sheath in direct-grounding boxes at both ends of the main section of cable cross-interconnection are measured; and then a new characteristic quantity is constructed using the amplitude ratio and phase ratio of grounding current at both ends of the same metal sheath circuit and the absolute value of phase difference of grounding current at both ends of different metal sheath circuits; and finally a characteristic quantity matrix corresponding to fault criteria is established to identify the faults based on multi-dimensional characteristic fusion. The common cable faults, such as the open circuit of the cable intermediate joints, the water infiltration into the cross-interconnection grounding box, and the short circuit of the cable intermediate joints, are analyzed, and the feasibility of the new fault criterion is verified by simulation, which can provide a new method for on-line monitoring of high-voltage cable faults.