A computer-controlled load loss standard for calibrating high-voltage power measurement systems

A computer-controlled load loss standard, based on the current-comparator technique, for calibrating high-voltage power measurement systems is described. Measurements can be made at any power factor from zero lag through unity to zero lead, positive or negative power, at voltages up to 200 kV, currents up to 1000 A, and 50 or 60 Hz. The load loss standard features current-comparator-based components including a high-voltage active divider, a unity-gain integrator for producing an accurate and stable reactive component, a high-current transconductance amplifier with the ability to provide a highly accurate current to a circuit that is operated at high voltage, and a computer for control and data reduction. In a laboratory environment the load loss standard has an uncertainty of less than 10 ppm for both magnitude and phase. However, when used for on-site testing/calibration, due to temperature effects, its uncertainty is increased to less than 100 ppm in magnitude and 10 ppm in phase.