Abstract: To quantitatively analyze the electromagnetic influence of the substation electrical system on the weak electrical system, it is necessary to first determine the normal operating and short-circuit fault current values of the electrical system. Therefore, by establishing a PSCAD simulation model, the current characteristics of 10 kV/0.4 kV transformers, cables, and switchgear under normal operation and grounding fault conditions are simulated, with a focus on analyzing and calculating the two-phase different-point grounding fault current values in the neutral-point ungrounded system.