ADVANCED CALIBRATION METHOD OF HIGH VOLTAGE AC POWER MEASURING SYSTEMS WITH REDUCED EFFORT AND MINIMIZED MEASUREMENT UNCERTAINTY

Summary

The new digital power measuring system called LiMOS based on a combined power measuring sensor has been developed as a space-saving alternative to conventional power measuring systems. Primarily for calibration of LiMOS, the new mobile Power Calibration System (PCS) has been developed and introduced at [1]. PCS uses a well-known physical definition of the electrical power, the product of simultaneously measured voltage and current. This calibration procedure is rarely used in a high voltage environment. Nevertheless the PCS has been calibrated by SP (Swedish National Metrological Institute) as reference standard of AC power. Furthermore the best measurement capability was confirmed by a bilateral round robin test with the PTB (German National Metrological Institute, “Physikalisch-Technische Bundesanstalt”). The calibration method is metrologically validated and therefore equal to other calibration methods. Lately the HIGHVOLT Calibration Laboratory extended its accreditation range for a new measurand, the AC electrical power. It is now accredited by DAkkS (Germany's accreditation body “Deutsche Akkreditierungsstelle”) for calibration with AC-power for apparent power in the range between 16 VA and 200 MVA and active and reactive power between 0 and 200 MW and 0 and 200 Mvar respectively with phase angle in the range between -90 and 90 degrees with best measurement capabilities of 0.04 % (400 ppm) for apparent, active and reactive power. The main advantages of this calibration process are that cross influences between current and voltage measuring branch are taken into account and that the certified uncertainty of the calibration represents the final uncertainty of the measurement system. This calibration method is universally applicable to any kind of power measurement systems.

Additional informations

Authors

Liao Yongli, Fan Jianbin, Wu Dong, Yujian Ding, Shi