The transient characteristics of electronic transformers must be tested by the direct method. The existing test methods have large investment and complicated control, which is not suitable for the field application. In order to overcome this problem, the test system which uses three power source system is introduced Through the computer waveform calculation, decomposition and combination of control, the transient characteristics of the test system provided a wide range of regulation capacity and composited the all-offset transient current. The test device can provide a true current test conditions. The test system can be used in factory test or delivery test for transformer in high-voltage power system has some guidance and application value.
