Volt-ampere characteristic experiment is the most common experiment item for maintenance current transformer in power system. In many places, power departments also require to make error curve for maintenance current transformer and report the error curve data to relevant management departments. Volt-ampere characteristic experiment corresponds to the exact name of the national standard and IEC standard is the excitation characteristic experiment. The purpose of performing the excitation characteristic experiment is to obtain the excitation characteristic curve of current transformer, and calculate the relevant parameters of current transformer according to the excitation characteristic curve to judge whether the current transformer can meet the requirements.
The error curve is based on the excitation characteristic curve and the secondary coil resistance of current transformer. The error curve establishes the relationship between the maximum allowable error of current transformer and the connected secondary load. As long as the short-circuit current of the current transformer system and the connected secondary load fall within the allowable range of the error curve, the maintenance current transformer can operate normally. Otherwise, the current transformer may fail due to magnetic saturation.
