**9.3 Comparison with the national energy standard**

Although the harmonic power standard equipment is designed for harmonic power measurements, it can also be used to measure power/energy under sinusoidal waveform conditions. A comparison against the National Primary Power Standard of the NIM is conducted under test conditions of 100 V, 5 A, 50 Hz, cos = 1, 0.5 lag, 0.5 lead, zero lag, and zero lead. The errors of the harmonic power standard equipment are no more than –18.6 W/VA at all the test conditions. This result is in agreement with previous findings within the evaluated uncertainties of the calibration/experiment.

Bilateral comparisons with the power standards of the National Metrology Institute of Germany PTB and USA NIST are also carried out using a traveling transfer standard under the test conditions 120 V, 5 A, 50 Hz, power factors of unity, 0.5 lag and lead, and zero lag and lead. The agreement is within 4 μW/VA at all the test points.
