Performance characteristics: automatic (manual) acquisition, measurement, display, storage and printing of all measurement parameters and AC impedance characteristic curves; real-time display of measurement data and AC impedance characteristic curves, convenient for storage and printing; double as single-phase transformer no-load, short-circuit Test and volt-ampere characteristic test of voltage (current) transformers and arc suppression coils; it has perfect over-voltage and over-current protection functions, in which the over-voltage and over-current protection value is automatically adjusted according to the setting of the test parameters, which is simple and guaranteed The safety of the tested equipment.