Bilateral comparison of current transformer measuring systems of NCHVM and PTB

An intercomparison of current transformer calibration systems was performed between National Center For High Voltage Measurement (NCHVM) and Physikalisch-Technische Bundesanstalt (PTB) in order to confirm their measurement capabilities. A current transformer was used as travelling standard with transformer ratios of 5A/5A, 10A/5A and 100A/5A at a frequency of 50 Hz and at ambient temperatures of 23°C±3°C. The measurements has been performed at test points varying from 5% to 120% of the rated current. For these three ratios, the test results differ by no more than 1.3 parts in 10
⁶
for the ratio error and 2.0 μrad for the phase displacement.