Precise Low-Cost Method for Checking Accuracy of Current Transformers Calibration Unit
Abstract
The paper presents a method for checking the accuracy of the commercial AC comparators used to calibrate current transformers. This method is simple and convenient and requires no special means of minimizing measurement uncertainty. Only conventional measuring instruments are used making this method cheaper for large amounts of laboratories. The analysis of the currents interrelation of a calibrated transformer and working standard allowed us to derive mathematical models of errors. The obtained models of the ratio error and phase displacement allow simulating different ratios of secondary currents. With the help of the proposed scheme, one can investigate the correctness of comparator readout. The obtained expressions of sensitivity coefficients made it possible to estimate the measurement uncertainty of the simulated reference values. The results of simulating errors from 1 to 1200 ppm for ratio error and phase displacement are presented. Reference values were compared with those obtained using a commercial comparator.
Event details
- Event
- tc4-2020