John J. Zelle

An improved three phase digital recorder system for calibrating power instrumentation

The paper describes an improved digital recorder system which is being used to provide reference values of voltage, current, active, reactive and apparent powers and harmonic quantities for three-phase sinusoidal and nonsinusoidal calibrations. The system has been designed to be used in the laboratory at the National Research Council of Canada (NRC) or transported on-site for tests in electrical utility facilities. Test results have shown that for sinusoidal waveforms, the accuracy of the voltage and current measurements of the digital recorder is better than 25 /spl mu/V/V or /spl mu/A/A of full scale and better than 50 /spl mu/W/W of full scale for active and apparent power measurements. The accuracy of the system for measurements under the seven distorted waveforms conditions most commonly used at NRC is better than 50 /spl mu/V/V or /spl mu/A/A of full scale for voltage and current measurements and better than 100 /spl mu/W/W or /spl mu/VA/VA of full scale for active and apparent power measurements.

A portable and stable source of AC voltage, current and power

This paper describes a portable and stable source of AC voltage, current, and power. It was developed for use with the National Research Council of Canada (NRC) watt-voltampere (W-VA) Transfer Standard to provide high-accuracy on-site calibrations of standards maintained by Canadian electrical utilities in order to establish traceability of these standards to the NRC. The stability of the source monitored over 100 s, a typical measurement cycle of the NRC W-VA Transfer Standard, is better than 10 ppm of full scale for the voltage and current outputs. The stability of its AC power output is better than 20 ppm of full scale at all possible power factor settings. The stable source is needed to minimize test uncertainties during on-site calibrations and to take full advantage of the accuracy of the NRC W-VA Transfer Standard. >

Intercomparison of nonsinusoidal calibration systems at NRC Canada and SP Sweden

A portable and stable source of ac voltage and current capable of generating sinusoidal and distorted waveforms was used as a means of comparing the nonsinusoidal calibration systems at the National Research Council of Canada (NRC) and the Swedish National Testing and Research Institute (SP). Comparisons of the test results obtained at the two laboratories were valuable in evaluating the performance of the two nonsinusoidal calibration systems especially when used to measure the amplitude and phase of harmonic voltages and currents in the presence of large fundamental components.

Watt and voltampere transfer standard

A new instrument which will be used as a transfer device between the national watt and VA standards of the National Research Council of Canada and the standards maintained by Canadian electrical utilities and electricity meter manufacturers is described. The relative error of this instrument is less than 50 ppm for power or energy and 100 PPM for voltampere measurements. The stability of the instrument during a field test cycle of about two weeks was on the order of 20 ppm. A dedicated pulse-frequency counter and a stable phantom power source were supplied to utilities to achieve high-accuracy on-site measurements. >

A tri-axis electromagnetic field meter (overhead power line field measurement)

The authors describe a portable instrument which measures AC electromagnetic fields using thee detection coils and analog computation circuits. The instrument has an accuracy of 0.5% for frequencies up to 3 kHz. Three measurement methods have been incorporated in the meter: wideband RMS (root mean square), wideband average, and 60-Hz average. The meter achieved faster and more accurate results than conventional single-coil instruments, since its design eliminates the time-consuming detector orientation requirements of those instruments. The results of a measurement program at an elementary school located at the edge of a high-voltage transmission line right of way are discussed. >

A new transfer device for the NRC Travelling Standard Program

The paper describes a measurement system, which is now used as a transfer device for the National Research Council of Canada (NRC) Travelling Standard Program. The system is based on two sampling voltmeters and a computer used for data acquisition and analysis. The equipment is used on-site with an ac source and a new 12-position pulse-frequency comparator to provide traceability for the standards maintained by Canadian electrical utilities and electricity meter manufacturers. The accuracy of the system is better than 30 parts in 10/sup 6/. The repeatability of the errors before and after an on-site calibration is generally better than 15 parts in 10/sup 6/.

New measurement capabilities of the NRC travelling standard program

This paper describes the improvements made to the National Research Council of Canada (NRC) Watt-VA Transfer Standard and to the AC source, which are used to support the NRC Traveling Standard Program. With these improvements, NRC clients can now calibrate on-site the voltage, current, active, reactive, and apparent power functions of their standards for rms voltages up to 600 V and rms currents up to 50 A.

An accurate RMS-DC voltage comparator

The authors describe a new instrument which is designed to operate as a null meter with a range of +or-1000 p.p.m. of typical test voltages used in high-accuracy AC calibrations. It is based on a commercially available dual-heater-type converter in a standard integrated circuit package. The accuracy of the instrument is better than 100 p.p.m. for frequencies of 50 Hz to 200 kHz. It can, however, be used for frequencies up to 1 MHz at reduced accuracy.<<ETX>>

Calibration of the thd functions of electrical standards

The paper describes a test procedure, the test waveforms, and the reference equipment used to calibrate the voltage and current total harmonic distortion (THD) measuring functions of multi-function electrical standards. It also shows that it is possible to establish traceability to the SI units for the THD measurements by measuring the voltage and power of the test waveforms with voltmeters and wattmeters that are traceable to SI. Results of recent calibrations are discussed.

A VA-meter-error analyzer

The authors describe a VA-meter-error analyzer which simulates the correct and simplified operating principles of commonly used VA meters. When used in the field, it displays directly the errors that VA meters operating on different principles would experience for the waveform conditions at the site. In sinusoidal or near sinusoidal conditions, the different operating principles result in identical readings. The readings diverge with increasing distortion. Analysis of the performance of the analyzer and interpretation of its results for simulated field conditions are discussed. >