Calibration of electricity metersAn electricity meter or a watthour meter measures the electrical energy passing through the meter and may be single-phase or poly-phase. The calibration assures that the measurement errors can be kept within the desired limits. By the regular calibration at SP the stability of the meter can be monitored closely.
The normal calibration method is to generate the desired power levels, and to compare the measured energy of the unit under test with the power measured by a reference system, usually by comparing the frequency of pulse outputs. For this purpose SP has reference systems with uncertainty level down to below 0.01 %.
The application may be one-phase or poly-phase and for low or high power factors. The frequency is normally 50 Hz but may be varied from 16.7 Hz to 400 Hz