High-accuracy sampling wattmeter

Author

Stenbakken, Gerard N. ; Dolev, Amos

Author_Institution

Nat. Inst. of Stand. & Technol., Gaithersburg, MD, USA

Volume

41

Issue

6

fYear

1992

fDate

12/1/1992 12:00:00 AM

Firstpage

974

Lastpage

978

Abstract

A high-accuracy sampling wattmeter was developed to investigate the feasibility of using waveform sampling techniques for making very accurate power measurements at frequencies from 50 Hz to 1000 Hz. The goal of this study was to develop an instrument having measurement uncertainty of less than ±50 p.p.m. over these frequencies. The wattmeter was built around a wideband instrument developed earlier, and it uses 16-b analog-to-digital (A/D) converters and includes a two-stage current transformer in one of the input modules. It operates with asynchronous sampling, and high accuracy is achieved by approximately synchronizing the interval over which sampls are taken with the period of the input signal. Special care was taken to design input stages with a flat frequency response and low temperature sensitivity. The wattmeter has been calibrated using an audio-frequency power bridge. The two instruments agreed to better than ±50 p.p.m. of full scale over the 50 Hz to 1000 Hz frequency range at all power factors

Keywords

analogue-digital conversion; power measurement; signal processing equipment; wattmeters; 50 to 1000 Hz; NIST; asynchronous sampling; audio-frequency power bridge; flat frequency response; power measurements; sampling wattmeter; temperature sensitivity; two-stage current transformer; waveform sampling; Analog-digital conversion; Current transformers; Frequency response; Frequency synchronization; Instruments; Measurement uncertainty; Power measurement; Sampling methods; Wattmeters; Wideband;

fLanguage

English

Journal_Title

Instrumentation and Measurement, IEEE Transactions on

Publisher

ieee

ISSN

0018-9456

Type

jour

DOI

10.1109/19.199445

Filename

199445