Method for Validation of Absolute Phase Angle Characterization in Wideband Current Shunts

This article describes the implementation of an absolute phase measurement system for the current “cage”-type shunts. The phase characterization of shunts includes phase difference measurements that allow realization of absolute phase using three geometrically equal shunts calibrated with dc. The measurement results for the three shunts are presented and analyzed in comparison to the values obtained by the lumped equivalent circuit model, which are metrologically compatible. Among the three shunts (2, 5, and 10 A), the 5-A shunt at 64 Hz showed the lowest uncertainty of 2.8
$\mu $
rad (
$k = 2$
). A new method for validating the results of absolute phase measurement of cage shunts using a digital impedance ratio bridge by applying the step-down technique was proposed. At 1 kHz, the 50-mA (16-
$\Omega $
) shunt had a step-down uncertainty of 6.5
$\mu $
rad (
$k = 2$
) and it was successfully compared with a digital impedance bridge (Digbrid).