A field test method is proposed for the intelligent substation’s magnetizing surge current restraint function and the function of test system’s each device and the overall implementation of the program is described. The test program uses DDRTS（ a digital power system simulation software） as a test system mainframe. By studying the generated mechanism of transformer inrush and waveform characteristics

the transformer magnetizing inrush model is built in DDRTS and the simulation data are transferred in real time synchronously to the main transformer’s three side sampling merging unit. The implement-ability of test method is verified through the actions of main transformer protection and fault recording.