Address:
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Bundesallee 100, FB 2.3 - AG. 2.32
, Ohmbau Room 314 Braunschweig, 38116, Germany
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Abstract:
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Abstract - The demand of electric energy is soaring worldwide and this tendency will surely persist in the future. Moreover, the deregulation of electricity markets has urgently been asking for enhanced traceability of calibrations in the field of electric power and energy. The industry heeding to these claims, placed modern electrical power standards into the market, which are able to synthesize complex alternating signals (ac) and power quality parameters in compliance with IEC power quality standards. These devices pose stringent calibration demands. In order to attend these urgent needs, much effort at the National Metrology Institute of Germany (Physikalisch-Technische Bundesanstalt - PTB) has been devoted to the development of novel and more accurate measurement methods of electric power and energy, and ultimately of power quality parameters, especially of highly distorted waveforms. Scientifically supported evidences suggest that, at the PTB, ac power in the range of power frequencies can nowadays be determined with measurement uncertainties typically around few parts in one million using very elaborated digital sampling techniques. The PTB primary power standard used to accomplish the most accurate measurements in laboratory has been enhanced in order to guarantee traceability of ac power to the SI (Système International d'unités) units in the range of frequencies from direct current (dc) to 5 kHz. Therefore, power standards for power quality parameters (like harmonics, flicker, fluctuating harmonics, and inter-harmonics) can be calibrated with measurement uncertainties as low as some tens of parts in one million. In this paper, the conducted investigations on the PTB primary power standard and measurement methods for power quality calibrations are clearly described. These methods can also be applied in secondary calibration laboratories depending on the available instrumentation.
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