In this paper, new traceable measurement systems for automatic calibration of high current sources have been established at the National Institute of Standards (NIS), Egypt. These systems can be used in laboratories mainly depending on calibrators with current coils, in case of unavailability of current transformers. Traceability of high current has been achieved to the primary standards of low voltages. NIS primary standards of DC and AC low voltages were used to realize the traceability to the International System of Units (SI) for DC and AC high currents up to 1000 A at 50 Hz. A traceable AC/DC clamp probe with calibrated nominal ratio of 1 mV/A has been used in the calibration system to realize high currents in terms of low voltages. Measurements have been automatically performed and controlled using the Laboratory Virtual Instrument Engineering Workbench (LabVIEW). Evaluations of results are presented and discussed. Normalized error (En) statistical method as well as error bar graphical representations are presented to prove that the new measurement systems are reliable and dependable for high current measurements. |
