Table 5 - Uncertainty budget of calibrating the high ac current at 350 A at 50 Hz by the second setup Uncertainty Sources Standard Uncertainty (%) Repeatability of the ac-dc difference Uncertainty of MJTVC Resolution of the DVM Accuracy of the DVM according to specification Uncertainty due to clamp transducer dc ratio Combined Uncertainty Effective degree of freedom Expanded Uncertainty at confidence level 95% (k=2) 6.5 × 10−4 1.1 × 10−3 5.0 × 10−4 6.9 × 10−3 0.15 Probability Distribution Normal Type A Normal Type B Rectangular Type B Normal Type B Normal Type B Divider 1 1 3 1 1 Sensitivity Coefficient (Ci ) 1 1 1 1 1 Uncertainty Contribution (%) 6.5 × 10−4 1.1 × 10−3 2.9 × 10−4 6.9 × 10−3 0.15 0.15 ∞ 0.30 Table 6 - Actual dc high currents values by the first setup associated with their expanded uncertainties Nominal DC Values (A) 50 100 150 200 250 300 350 700 1000 DC Current Actual Value (A) 50.01 100.05 149.97 200.01 250.00 300.04 349.97 699.84 999.95 Expanded Uncertainty (A) 0.15 0.30 0.45 0.60 0.75 0.90 1.05 2.10 3.00 Expanded Uncertainty (%) 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 Table 8 - Actual ac high currents values up to 350 A at 50 Hz by the second setup associated with their uncertainties Nominal Values (A) 50 100 150 200 250 300 350 AC Current Actual Value (A) 50.08 100.04 150.01 200.05 250.04 300.10 350.01 Expanded Uncertainty (A) 0.15 0.30 0.45 0.60 0.75 0.90 1.10 Expanded Uncertainty (%) 0.30 0.30 0.30 0.30 0.30 0.30 0.30 Table 7 - Ac-dc differences (δdiff uncertainty Nominal Values (A) 50 100 150 200 250 300 350 34 50 Hz δdiff , ppm -50 -47 -13 -31 -35 22 25 TypeA, (ppm) 18 23 21 10 12 12 6.5 δdiff , ppm -16 30 28 12 26 -12 -13 ) and Type A Table 9 - Actual ac high currents values up to Nominal Frequency 100 Hz TypeA, (ppm) 22 40 17 10 11 12 12 Nominal Values (A) 50 100 150 200 250 300 350 350 A at 100 Hz by the second setup associated with their uncertainties AC Current Actual Value (A) 50.01 100.07 150.11 200.25 250.12 300.02 350.00 IEEE Instrumentation & Measurement Magazine Expanded Uncertainty (A) 0.15 0.30 0.45 0.60 0.75 0.91 1.10 Expanded Uncertainty (%) 0.30 0.30 0.30 0.30 0.30 0.30 0.30 May 2022