Andrés E. Legarreta, Javier H. Figueroa, Julio A. Bortolín
AN IEC 61000-4-30 CLASS A POWER QUALITY MONITOR DEVELOPMENT AND PERFORMANCE ANALYSIS

Power Quality assessment is today one of the main ways to improve energy efficiency. International standards tend to restrict the way this assessment is done, by defining the measurements methods that should be adopted by an instrument. This work describes some of the constrictions and requirements assumed for the design of the high performance Power Quality data logger PQ1000, taking into account the international standards IEC 61000-4- 30 Class A and the IEC 61000-4-15 published in August 2010. Trough it, the most important demands of the IEC 61000-4-30 class A instruments are exposed. Details of the hardware components are also shown, and the most important points of the signal processing path are explained. The performance in the RMS values determination is given, also the frequency response for harmonics measurement are shown, and a detailed analysis of fulfillment of the tests given in the IEC 61000-4-15 ed. 08-2010 are given in the final section. Before the publication of this ed.08-2010 the Cigrè C4.1.01/CIRED 2 CCO2/UIE WG2 - 2004 protocol was the reference document that in addition with the IEC standard was used for the evaluation of digital flicker meters. This protocol aim is to guarantee a higher degree of compatibility between instruments of different manufacturers and models. The tests here presented intend to submit the equipments to a more real situation, and try to show possible hardware or firmware defects. The results given by the PQ1000 widely surpasses the standards exigencies.

D. Slomovitz, L. Trigo, C. Faverio
TWO-STAGE ELECTRONICALLY COMPENSATED CURRENT-TO-VOLTAGE TRANSDUCER

To fulfill the requirements of very high accuracy wattmeters, a current to voltage transducer was developed. The nominal input currents go from 1 A up to 100 A, and the nominal output voltage is 2 V. The goal is to get uncertainties in the order of 1 part in 106.

Michael Coleman
THE DEVELOPMENT OF A HIGH-TEMPERATURE PRT CALIBRATION PROCESS BASED ON DRY-BLOCK CALIBRATORS

Industry trends are leading toward the need for improved accuracy in field calibration applications. The dry-block calibrator is the most common type of heat source used in field temperature calibrations but can be difficult to correctly address in a comprehensive uncertainty analysis. Significant sources of error or uncertainty are often overlooked or underestimated. It is proposed that through the use of modern best practices in temperature metrology, the sources of error can be properly accounted for and managed to result in calibration uncertainties from 20 to 50 mK (milliKelvin) over the range -40 to 660 °C in a dry-block calibrator based PRT (Platinum Resistance Thermometer) calibration system. This will be demonstrated through the presentation of a system recently designed for a commercial secondary-level calibration laboratory.
Included in the paper are a comprehensive uncertainty analysis as well as the problems, solutions, and results encountered during the design of the process. The intent of this paper is to help calibration professionals in industry recognize and properly deal with sources of uncertainty related to dry-block type calibrators in temperature calibration processes. With modern best practices in temperature metrology it is possible to achieve reliable high-accuracy temperature calibrations, even in the field.

Joalbo Borges Santos, Amauri Oliveira, Carlos Eduardo Trabuco Dórea, Daniel Gonçalves de Souza Neto,Tanguy Phulpin
APPLICATION OF FEEDBACK LINEARIZATION IN THERMORESISTIVE SENSORS CHARACTERIZATION AND FEEDBACK MEASUREMENT SYSTEMS

This paper presents the application of feedback linearization for the characterization of thermoresistive sensors and for feedback measurement systems using these sensors kept at constant temperature. This technique allows the generation of an input signal which is proportional to the electric power of the sensor, simplifies the characterization with the possibility of determining thermal conductance and intrinsic time constant of the sensor in a single test. Concerning the feedback measurement system, this technique improves features of the measurement system with the possibility of use a simple linear controller with good performance in the operation point. Experimental results of characterization and measurement are presented.

R. Caballero, J. Diaz de Aguilar, Y. A. Sanmamed, M. Neira
CALIBRATION OF NON QUADRATIC SENSIBILITY THERMAL CONVERTERS

A measurement system for the ac-dc transfer difference of thermal converters whose power response is not exactly quadratic is presented. The previous method, due to the simplifications of the equations, was not valid for those ac-dc transfer standards with a sensibility slightly different from 2. The error in using these equations for those standards has been evaluated and can be as high as 20 μV/V when dealing with single junction thermal converters whose sensibilities can be around 1.6. In the new measurement system, some terms, before considered negligible, have been retained. A modified bridge has been developed according to this equation to allow the calibration of all kind of thermal converters, including those with sensibilities not exactly quadratic. This new bridge has been validated with some measurements as detailed below in this paper.