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Relatrio Final - Perez Guerrero.docx

1. 1 Sienna SIM T amp F iterar de COPY Caco Trazalbibdad IlEFE 4898 i 7 Contador de de TIA Ihecuencia incertidumbes 1110 Cron ntro aga ial y HA Wu oo dy y Ei copor campo adcinoo de oscilador mino pa Ondas c mpo Gabo crondendtr I Ondas campo elcnico deter Figura 2 Diagrama de bloques del m todo de calibraci n El receptor de campo consiste en un blindaje para disminuir las inducciones externas y aislar las inducciones producidas por el cron metro La siguiente etapa es el circuito depurador y adaptador de se al Figura 3 con el cual se logra acondicionar la se al de 215 Hz para su medici n con las siguientes etapas que consisten en equipo comercial y Acople de i impedancias Amplificador Inversor Lirnitador tensi n Filtro paso banda de banda angosta Acoplador impedancias frecuencimetro Figura 3 Diagrama de bloques del depurador y adaptador de se al En Figura 4 se muestra la se al procesada que se mide con un contador de frecuencia con trazabilidad al SI mediante el patr n primario del ICE Se nota la calidad de la se al obtenida luego del circuito depurador y adaptador que optimiza la frecuencia del oscilador de cuarzo del cron metro y minimiza las otras componentes de menor frecuencia y mayor amplitud original A O nn HL 0 A 0 A N SLOP CHI 2 V ITB 200us AL Figura 4 Senal generada para el muestreo de la frecuencia del oscila
2. Once the samples are stored Swerlein s algorithm calculates the RMS value of each signal Another approach to calculate RMS values of each harmonic is the extension of Swerlein s algorithm developed by Kyriazis 8 In this work the algorithm adjusts the parameters of the samples in a Fourier series in the frequency domain using least square adjustment The samples are fitted to the following equation Nharm Ay 2 4 sin 27 jft B cos 2z jft 1 where i denotes the sample taken al time t and k denotes de burst All the sampling data for each burst are store in the memory of a PC Once the samples are store in the PC we process them with an algorithm developed by Pogliano in 7 In this algorithm the signals are assumed to be described as Fourier functions of time as u t U SU 2 cos 2hz ft U V2 sin 2hz ft 2 i t I Pla V2 cos 2hz ft 1 2 sin 2h7 fr where U U U 1 1 and 7 are respectively the dc component and the rms value of the cosine and sine hy harmonic components of both voltage and current and f is the frequency of the fundamental The first step in Pogliano s approach is determine the parameters U U U by least square adjustment by minimizing the sum of the squares of the residuals R Y u 1 n l 2 Su 4 where Su is the N voltage samples taken at times 1 while the values u t are the estimated coefficients This is the first
3. Fig 2 DCC results R 10 mW Rp210 mW j 1 0 For R 10 mW the measurement current of 100 mA was applied to each tested resistor only for the period of about 600 s necessary to measure its value with a standard deviation below 0 005 uQ O For Ra 10 mW the measurement was made at the same level of power but by continuously applying the measurement current to the tested resistor for at least 24 h prior to the measurement The DCC bridge reference resistors were measured under continuous power 1779882 2008 O 2 1874 0 5431 1779885 2008 DS 2 0750 0 5461 1842307 2008 pf 2 8136 0 5252 Barometric pressure and humidity can affect the value of some resistance materials Higher valued resistance standards made from Manganin are packaged in sealed metal enclosures for this reason In unsealed wire wound resistors the response to pressure is give by Eq 2 and the coefficient y depends on the material properties of the wire For bare Manganin the pressure coefficient is positive and has a value of approximately 2 3x10 kPa 4 For Evanohm alloys this pressure coefficient of resistance is smaller and negative approximately y 1 1 x 10 kPa The pressure coefficient for unsealed NML 1 Al resistos is known to be approximately of this magnitude 5 6 Tests on two NML resistors have shown no effect on the resistance values for different relative humidity levels below 60 The properties of the material used for supporting
4. Well defined resistors with high stability and low residual reactances are available in metallic film units and resistors of this type are used Their impedance ratio should preferably be evaluated However the resistance ratio at power frequencies can be estimated from the dc resistance ratio R R within a few parts in 10 In addition by symmetrical construction the phase angles of the resistors may be assumed equal within a few microradians With these simplifying assumptions Dd V R Zs Ml R 8 arg 1 arg I argV argV Assuming a nondissipative standard capacitor i e tan ds 0 the reference values of dissipation factor and capacitance ratio for an unknown capacitor are from 4 and 8 tan Oy tan argV argV S AE ora i K Cs ref v R j 10 MHz Out HIGH VOLTAGE CAPACITANCE AND DISSIPATION FACTOR BRIDGE Input Input GPIB Fig 3 Calibration system 5 MEASUREMENT PROCEDURE DVM I master assumes the role of establishing the timing for the whole sampling process DVM2 slave is configured for external triggering it samples its input signal only when DVM1 sends through an output connector of the instrument a digital signal to the trigger input of DVM2 indicating when a reading is being carried out Therefore the digital circuits of the two converters are linked through a fixed delay VIII Semetro Jo o Pessoa PB Brazil June 17 19 2009 The fundame
5. central de la serie y en ambos extremos es suficiente para determinar su influencia en todos los puntos q Q O x e Se UA wm awh jr b ma CS Fig 3 Esquema el ctrico del divisor Se calcula la relaci n 1 10 a partir de las mediciones Las siguientes ecuaciones definen el error del voltimetro durante el procedimiento Y1 Y2 lt gt Zi E E 6 E 7 donde Yi son las lecturas de la tensi n de 10 V mientras que Zi son las lecturas de 1 V correspondientes a cada resistor de la serie Los valores de amp corresponden a los errores El error promedio e vale p Ea tE 8 gt 8 Esto es un valor de e positivo indica que la lectura de 10 V del volt metro es mayor a 10 veces la lectura de 1 V Este mismo procedimiento se usa para calibrar el rango de 100 mV del mult metro respecto a los anteriores Una vez calibrado el mult metro se procede a medir la tensi n del patr n que se desea comparar con el Josephson fuentes zener o pilas patrones de 1 018 V y 10 V Se asume que el error hallado para la relaci n 10 1 es el mismo que para la relaci n 10 1 018 La incertidumbre de esta comparaci n depende de los valores de FEMs termoel ctricas impedancia de entrada del volt metro estabilidad de las lecturas resoluci n de las lecturas tensiones de offset y resistencia de los cables de conexi n Cada medida se determina a partir de 3 mediciones individuales realizadas en d as diferentes
6. o 3 32769 998 W 32769 996 32769 99 T 7 7 7 7 7 1 1 1 j 0 100 200 300 400 500 600 700 800 900 1000 N mero de mediciones Figura 6 Medici n de simulaci n con um sintetizador de 32770 Hz Un ejemplo real de mediciones de un cron metro se muestra en la Figura 7 Se nota que se mantiene el ruido del sistema medido en la Figura 6 y las variaciones propias del oscilador del cron metro durante 1000 mediciones realizadas cada 3 segundos el numero de mediciones y la ventana de tiempo de medici n son programables En la Tabla 1 se muestran los datos de las primeras 10 mediciones Tabla 1 Primeras 10 mediciones de frecuencia de un total de 1000 de oscilador interno del cron metro del laboratorio considera la resoluci n de un contador de frecuencia de 11 d gitos 1000 mediciones con ventana de tiempo de 3 segundos ruido del sistema medido en condiciones extremas de bajo nivel de se al de un objeto simulado con un generador sintetizado Tabla 2 Cuadro comparativo de las incertidumbres de los m todos de calibraci n Incertidumbre s 1 sigma Fuente de M todo manual M todo inductivo incertidumbre Resoluci n del 0 0029 8 8x10 objeto o contador 12 Base de tiempo 5 8x10 5 8x10 09 Ruido de sistema 0 17x10 Reacci n manual 0 10 0 Variabilidad 0 040 1 5x10 de mediciones Incertidumbre 01 09 comh nada
7. 450 452 Apr 1999 4 G Ramm and H Moser Calibration of electronic capacitance and dissipation factor bridges JEEE Trans Instrum Meas 52 n 2 pp 396 399 Apr 2003 5 G Ramm H Moser and A Braun A new scheme for generating and measuring active reactive and apparent power at power frequencies with uncertainties of 2 5 x 10 IEEE Trans Instrum Meas 48 no 2 pp 422 426 Apr 1999 6 G A Kyriazis and M L R Campos An algorithm for accurately estimating the harmonic magnitudes and phase shifts of periodic signals with asynchronous sampling IEEE Trans Instrum Meas 54 no 2 pp 496 499 Apr 2005 7 G A Kyriazis Calibration of high voltage current comparator based bridges using nonsynchronous digital sampling CPEM Digest Broomfield USA Jun 2008 pp 198 199 8 G A Kyriazis Calibration of high voltage current comparator based bridges using nonsynchronous digital sampling IEEE Trans Instrum Meas 58 no 2 Apr 2009 in publication 9 G A Kyriazis R T B Vasconcellos L M Ogino et al Design and construction of a two terminal pair coaxial capacitance bridge in Proc of the VI SEMETRO pp 57 62 Rio de Janeiro Sep 21 23 2005 10 G M Rocha and G A Kyriazis A software for the evaluation of the stability of measuring standards using Bayesian statistics in Proc 13 IMEKO International Symposium on Measurements for Research and Indu
8. En ensayos realizados se estim las incertidumbres tipo A en 1 8 x10 La combinaci n de los tipos A y B resulta en un total de 3x10 Este valor es posible reducirlo con un dise o nuevo del divisor resistivo que permita comparar directamente el Josephson y la fuente patr n a calibrar sin necesidad de usar el mult metro Este proyecto est en desarrollo 4 CONCLUSIONES Se desarroll un sistema Josephson no convencional de alta temperatura Este proyecto que a n no est finalizado ha logrado obtener escalones qu nticos para los niveles de 60 mV siendo la pr xima meta alcanzar 100 mV con lo cual las incertidumbres mejorar an considerablemente Se est implementando un sistema autom tico de medidas y an lisis estad sticos de las mismas y un divisor de tensi n de relaci n variable de 3 d cadas controlado por el mismo sistema para lograr incertidumbres menores acordes a los sistemas Josephson convencionales REFERENCIAS 1 A M Klushin M He A S Katkov Constant Voltage Steps at 0 1 Volt from a Series Array of High Tc Josephson Junctions CPEM 2008 Broomfield June 2008 2 H de Souza D Slomovitz Comparaci n de patrones el ctricos en tensi n continua mediante un divisor 10 1 IEEE Lat Amer Transactions vol 4 No 3 pp 12 15 May 2006 BIOGRAF AS Heriguat de Souza naci en Salto Uruguay en 1955 Recibi el t tulo de Ingeniero Tecnol gico en la Universidad del
9. INTN Asunci n Paraguay rob_duarte hotmail com robertduarte intn gov py Abstract This work aims to present current situation of electrical metrology implemented in the INTN describing the actions taken as body responsible or metrological control into the State of Paraguay and as responsible for establishing and maintaining the chain of traceability in the country The present paper intend to present the starting point since 2 001 when the INTN had not participation en electrical metrology area until activities and results reached to date as well programs and projects already confirmed for the short term Keywords meter pattern primitive standard 1 INTRODUCCION El Instituto Nacional de Tecnologia Normalizaci n y Metrolog a INTN es el Instituto Nacional de Metrolog a INM en el Paraguay en base a la Ley N 937 82 as como al Decreto Reglamentario N 1988 99 de dicha Ley En ambos documentos se establecen como principales responsabilidades del INM a Establecer los programas nacionales referentes a la Metrolog a Cient fica e Industrial y b Establecer los programas y aplicar las reglamentaciones atinentes a la Metrolog a Legal Las actividades de control metrol gico se iniciaron en Paraguay en la d cada de los 80 enfocados en el rea de volumen verificaci n de surtidores de combustibles l quidos y en el rea de masa grandes balanzas A medida que transcurrieron los a os fueron increment nd
10. Posicionamiento Presi n E hie A ae Chip Josephson A E Bomba de vac o Fig 1 Diagrama en bloques del sistema K Nitr geno l quido Helio gas En un computador se ejecuta un software con el cual se ajustan los valores de varios par metros se mide la temperatura se visualizan en la pantalla la forma de los escalones cu nticos se selecciona los niveles de corriente para los cuales estos escalones se visualizan verticales y estables ver Fig 2 Los par metros a configurar son frecuencia y potencia de la microonda corriente cr tica temperatura selecci n de corriente en el escal n tiempo de inversi n de polaridad etc Synthesizer v1 1 27C PID Frequency MHz Power mW 74605 6 0 4 30 2 z ae Amplitude gt JGJ 10 75000 40 Temperature PID Control Scan Generator Triangle Constant SCAN ON 74000 30 73000 Heater ON 20 72000 105 1 CAME SetPoint K 70000 Y Temp ON e Volt Out IVC Voltmeter 101 0 Stop Excel RESET 0 Synthesizer AAN Frequency MHz Power mW Temperature PID Control Scan Generator Temp Amplitude 74605 6 0 4 30 6 76 7 20 in Triangle GO OG Tr i i 75000 407 100 i 7 PID Constant J SCAN ON 74000 73000 O Heater ON 72000 105 1 a 71000 ful 70000 SetPoint K Temp ON O Volt
11. calculable frequency characteristic has to take into account parameters of a tee used to transfer reference values to the tested converter This would require an additional characterization of the tee used at a given calibration To avoid this extra step we have therefore decided to increase accuracy of the calculable reference converter by incorporating the tee in its design A schematic of the calorimetric thermal voltage converter with a built in tee is shown in Fig 1 Fig 2 shows a photograph of the converter during and after the final assembly The input test voltage is applied to the measurement reference plane the center of the tee via the side arm type SMA connector A test converter is connected to the type N female connector of the test arm of the Tee The electrical length of this arm was designed to be equal to the electrical length of the arm of a regular type N Tee model UG 107B U The AC DC difference of the test converter is compared to a calculable AC DC difference of a reference converter fabricated at the second reference arm of the Tee The reference arm consists of a short coaxial line terminated by a miniature microwave rod resistor heater A thin copper disk electrically completes the heater circuit The coaxial line thermally insulates the heater resistor from the body of the converter and the input connectors It is built from two thin wall stainless steel tubes the outer surface of the inner tube conducto
12. campo de la Metrolog a El ctrica buscando dar mejor soporte t cnico y de trazabilidad a las mediciones de empresas fabricantes de equipos y material el ctrico adem s de apoyar el aumento de la competitividad de los mismas Por otro lado se pretenda dar el apoyo VIII Semetro Joao Pessoa PB Brazil June 17 19 2009 necesario a las empresas que buscan la certificaci n de productos y servicios en base a las normas de la serie ISO 9000 7 CONCLUSIONES Mediante la implementaci n de las etapas de control metrol gico se ha logrado a que solamente los medidores que se ajustan a los valores nominales de tensi n y frecuencia de la red de distribuci n de Paraguay ingresen al mercado y sean instalados a los usuarios b se ha podido dar certeza que los medidores nuevos instalados a los usuarios cumplen son las tolerancias establecidas en la normas IEC aplicables y c se ha podido establecer al INTN como un organismo de tercera parte que pueda dirimir en los conflictos entre proveedor usuario A trav s de la implementaci n de los controles metrol gicos se ha podido iniciar y sostener un programa de trazabilidad a nivel nacional en este caso en energ a el cual significa el inicio de un ambicioso proyecto que a o a a o va expandi ndose a otras magnitudes lo que se juzga como fundamental y estrat gico para el Paraguay considerando su condici n de pa s exportador energ tico REFERENCIAS 1 Ley Nacional de Me
13. este problema normalmente se presenta cuando al enfriar el chip se tiene la influencia de un campo magn tico externo que provoca que en el superconductor circulen peque as corrientes que mantienen el flujo magn tico y que evitan el correcto funcionamiento del patr n Para evitar este problema el chip est blindado con un material de muy alta permeabilidad que requiere ser desmagnetizado con cierta frecuencia Es com n tener problemas de flujo atrapado en los chips de efecto Josephson usualmente el problema se resuelve cuando se saca el chip del helio l quido se deja calentar un poco hasta que las uniones Josephson salen del estado superconductor y se enfr a nuevamente Sin embargo cuando esto se hace en repetidas ocasiones y no se elimina el flujo atrapado no se puede operar el patr n debido a que no se puede asegurar el valor de la tensi n Josephson En el Laboratorio de Tensi n El ctrica Continua del CENAM tuvimos el problema de flujo atrapado en repetidas ocasiones intentamos varias soluciones y la que mejor nos funcion fue cambiar la t cnica de enfriamiento Usualmente al enfriar se recomienda poner un corto circuito en los cables que se conectan al chip Josephson lo que VIII Semetro Jo o Pessoa PB Brazil June 17 19 2009 probamos fue enfriar el chip manteniendo la fuente de polarizaci n conectada y haciendo un barrido de tensi n en el chip con esto disminuyeron considerablemente los problemas de flujo
14. interval as determined from a least squares fitting procedure Temperature characterization curves are measured with the resistor temperature held constant at several values that span the useable range typically between 20 C and 30 C For some resistors temperature cycling in this range may reveal a small and reversible change hysteresis in the value at T Because laboratories are located at various elevations above sea level another significant influence on the resistors used in international comparisons is barometric pressure The dependence on pressure is described by R P R 1 y P P gt 2 where R P is the resistance at pressure P R is the resistance at a reference pressure P and y is the coefficient of resistance versus barometric pressure An important part of any comparison is to understand and eliminate all such external influence factors in order to compare the maintained standards and measurement methods in use at each laboratory Ideal transport standards of resistance should be stable under external influences so that they provide reproducible values under similar conditions in different laboratories after accounting for linear drift with time This paper describes how the process of characterization and selection of 1 Q resistors provides an understanding of the behavior of the standards reduces the uncertainty of the results and ensures that the critical comparison results 1 e the participating
15. not unlike a coaxial calorimeter for RF power measurements its frequency characteristic can be estimated theoretically from a number of mechanical and electrical parameters An internal Tee integrated into the CTVC improves calibration accuracy of working standards Over the years several of these converters have been manufactured for different operating voltages and with different frequency characteristics leading to an optimized design with a frequency characteristic practically flat over eight decades of frequency The paper describes details of construction of the CT VC Results of RF DC voltage transfer difference measurements AC DC current transfer difference and uncertainty evaluation of the converter are discussed Keywords AC DC transfer standard thermal converter calorimetric converter transmission line 1 INTRODUCTION AC DC transfer difference of the highest accuracy primary standards multijunction thermal voltage converters MJTC can be determined theoretically with an uncertainty of a few parts in 10 but only in a limited frequency band Above approximately 5 kHz to 10 kHz the calculable frequency independent thermoelectric components of the AC DC transfer difference are dominated by the frequency dependent components The latter ones originating in the skin effects and stray reactances in the MJTC physical structure are difficult to calculate accurately For this reason in a higher frequency range up
16. terrestres por relojes at micos primarios cesio pudiendo realizarse correcciones a los sat lites que componen el sistema Sin embargo los sistemas GPSDO poseen alto ruido en medidas de corto plazo ver Fig 2 9999999 99655 9999999 99650 AI NN Hil TN 9999999 99645 N AIN 9999999 99640 i Frecuencia Hz iil i 9999999 99635 4 9999999 99630 9999999 99625 T T T T T T T 0 tiempo min Fig 1 Gr fico de la se al del rub dio 9999999 9980 9999999 9975 9999999 9970 i 9999999 9965 9999999 9960 Mai 9999999 9955 Frecuencia H2 9999999 9950 9999999 9945 1 9999999 9940 T T T T T T T T T 0 10 20 30 40 50 60 70 80 90 100 tiempo horas Fig 2 Gr fico de la se al de salida del GPSDO Los patrones primarios est n constituidos por osciladores at micos de Cesio su frecuencia no se altera con el tiempo Mediante el seguimiento de algunos par metros se conoce cu ndo est n llegando al l mite de su vida til Esta puede ser de alrededor de diez a os en los equipos comunes y de cinco a os en los de alta performance Al llegar al fin de su vida til es necesario reemplazar la ampolla donde reside el cesio y parte del sistema de funcionamient
17. the resistor element also can change with pressure and with chemical action and these changes can be transmitted to the resistor element In particular NML resistors are constructed with silicon rubber rings to provide soft flexible constraints where the element is attached to its support This material swells when it is placed in silicone oil with the result that the resistor changes significantly in value due to strain and or pressure Only mineral oil should be used in oil baths that are used to maintain NML type resistors Thomas type resistors are constructed with soft solder seals between the inner and outer walls of their enclosures and with the resistor elements sealed in dry nitrogen gas The thin brass inner wall does expand and contract somewhat due to external pressure changes resulting in typical pressure coefficient values in the range of 2x10 kPa to 8x10 kPa Characterization tests have shown that some Thomas type resistors have apparently lost the integrity of the metal to metal seal a condition that increases their pressure coefficients to 2 2 x 10 kPa to 2 4 x 10 kPa 6 Pressure coefficients are especially important in 1 QL Thomas type resistor comparisons because of the effect of altitude on barometric pressure Equation 3 gives an approximate relation that describes the pressure kPa P 5 30x107A 1 198 x 10 A 101 325 3 Here the altitude A is in meters and P is adjusted to standard atmo
18. 2 2x10 3 4x10 8 8 8 8 8 3 CONCLUSIONES Se logo la medicion de la senal basica del oscilador de cuarzo de cron metros para su calibraci n Se reducen las principales componentes de incertidumbre de calibraci n del tiempo de reacci n manual del metr logo o la resoluci n del objeto a la resoluci n del contador de frecuencia y la variabilidad propia del objeto El sistema manual usado anteriormente requer a mediciones durante varis d as para reducir la representatividad de la reacci n manual El sistema nuevo solo requiere mediciones de horas o minutos para conocer la desviaci n del objeto en corto plazo El sistema tambi n permite las mediciones a largo plazo sin necesidad de intervenci n humana por ser un sistema automatizado N 1 2 3 4 5 7 10 Lo 2 MEA 4 E 6 03 11 2008 03 21 06PM 32768 136481 _ 7 o 3 8 f 9 10 i AGRADECIMENTOS Al Ing Carlos Quevedo de SIC Colombia por su valiosa informaci n para iniciar este proyecto REFERENCIAS 1 2 Dell 3 Quevedo C A 2007 Determinaci n de la frecuencia de oscilaci n de cron metros Manuscrito no publicado Superintendencia de Industria y Comercio Colombia Gust Jeff C Graham Robert M Lombardi Michael A 2004 Stopwatch and timer calibrations Extra do el lunes 01 de septiembre del 2008 de http tf nist gov general paf 1930 paf Trigo Leonardo Slomovitz Da
19. 3458A La se al de tensi n a 6V a trav s del divisor inductivo de tensi n y la se al de corriente a 2V mediante el convertidor de corriente con resistencia incluida Las se ales son muestreadas por los mult metros para luego ser procesadas por el computador donde se realiza el c lculo de la potencia el ctrica Voltaje Corriente E Fig 1 Esquema general de los elementos que componen el Sistema de Potencia 2 PROPOSITO DEL PROYECTO La g nesis de este proyecto ha sido la enorme dificultad para mantener en estado de calibraci n permanente el Patr n Nacional de Potencia y Energ a El ctrica existente en el CENAMEP Es necesario enviarlo por lo menos una vez al a o a la F brica ubicada en Alemania o a un Instituto Nacional de Metrolog a INM ya sea en EEUU Argentina o M xico Ello conlleva altos costos riesgos de da os durante el transporte e inclusive la p rdida de la calibraci n por golpes y tambi n el tiempo que demandan esos INM para efectuar la calibraci n contribuye negativamente Lo ideal ser a que el futuro Patr n Nacional de Potencia El ctrica de alta exactitud pueda calibrarse directamente en el CENAMEP AIP Para ello el objetivo del Proyecto es alcanzar un error maximo del Patr n propuesto inferior a 50 partes por mill n 50 ppm 3 BENEFICIOS Y PRINCIPALES BENEFICIARIOS Los beneficios de este Proyecto si se alcanza el objetivo de materializar la Magnitud Potencia El ctrica con
20. Masa y Grandes Masas brinda los servicios de calibraci n de pesas balanzas de precisi n y de gran capacidad El Laboratorio de Masa est acreditado por el DKD de Alemania para la calibraci n de pesas clase E2 F1 F2 y M1 desde 1 mg a 1 kg Nuestro Laboratorio de Temperatura cuenta con la acreditaci n del DKD de Alemania para la calibraci n de term metros de resistencia y term metros con indicadores digitales desde 40 C hasta 250 C El Laboratorio de Longitud y ngulos realiza las calibraciones de una serie de instrumentos empleados en la industria y de bloques planoparalelos grado 0 El Laboratorio de Volumen y Densidad y Flujo realizan calibraciones de materiales de vidrio y medidores volum tricos de peque a y gran capacidad hasta 5000 L aprobaci n de modelo de medidores de agua calibraci n de banco de ensayos de medidores de agua y calibraci n de medidores de flujo hasta 108 m h El Laboratorio de Fuerza y Presi n Cuenta con patrones para la calibraci n de man metros balanzas de peso muerto torqu metros y m quinas de ensayo hasta 2 MN en compresi n y hasta 500 kN en tensi n El Laboratorio de Metrolog a Qu mica realiza calibraciones de pHmetros conductivimetros analizadores de gases vehiculares y an lisis de bebidas alcoh licas Estamos desarrollando sistemas secundarios de medici n de pH y conductividad para la producci n de materiales de referencia El Laboratorio de Ac stica cuenta con patrone
21. Out VI START Voltmeter Stop IVC Voltmeter 2101 0 Auto Scale Stop C Excel 0 Cursor Menu Clear Curso Cursormenu Zero v Plot Chart Fig 2 Pantallas del software Un sintetizador multiplicador de frecuencia genera las microondas con las cuales se irradian las junturas Este se comunica v a RS232 con el computador y el software es quien se encarga de controlar la frecuencia y la potencia de la microonda Esta es generada a partir de una senal 10 MHz que provine del Patr n de Frecuencia del Laboratorio Reloj At mico El sintetizador entrega en su salida una frecuencia en el entorno de 70 a 75 GHz la cual se acopla al chip por medio de una gu a de onda y un resonador Fabry Perot El chip de junturas Josephson est dentro de un blindaje magn tico de alta permeabilidad al final de una puntera deslizante criog nica que hace la transici n entre el helio el nitr geno Por un tubo central pasan varios pares de conductores de cobre desde el chip a los comandos Una tarjeta generadora y adquisidora es la encargada de generar la se al de corriente que se aplica a las junturas realizar las medidas de la tensi n en dichas junturas en una funci n de osciloscopio con 16 bits de resoluci n realiza la medida de temperatura controla los tiempos entre los cambios de polaridad de la tensi n de salida etc Todas las funciones de la tarjeta son controladas via comunicaci n USB por
22. Patr n de efecto Josephson 1 INTRODUCTION En 1994 el CENAM adquiri un sistema de efecto Josephson de la compa a Research Manufacturing Company que comercializaba el desarrollo del NIST El sistema se adquiri con dos chips que permit an generar niveles de tensi n cu nticos en el intervalo de 1 V a 1 V y en el intervalo de 10 V y 10 V Frecuencia de referencia de 10 MHz Contador de Frecuencia Oscilador a M 75 GHz int ij He l quido Fuente de polarizaci n Adicional H Chip Josephson Tensi n de salida Fig 1 Diagrama a bloques del patr n de efecto Josephson VIII Semetro Joao Pessoa PB Brazil June 17 19 2009 Los principales elementos del patr n de efecto Josephson son dos chips de 3660 uniones 1 V y de 20208 uniones 10 V con tecnolog a SNS El sistema de microondas que genera una se al del orden de 75 GHz est basado en un oscilador a diodo Gunn cuya frecuencia se estabiliza y se mide por medio de un contador de frecuencia EIP 578B que tiene como referencia de frecuencia externa de 10MHZz un reloj at mico de Cesio La se al de microondas se conduce por medio de una gu a de ondas diel ctrica al chip colocado dentro de un criostato que contiene helio l quido Una fuente de polarizaci n permite ajustar el patr n a un cierto nivel de tensi n cu ntico deseado La fuente de polarizaci n incluye tambi n un sistema de barrido y conexiones a un oscilo
23. The box has an N type input connector and a BNC type output connector The standard capacitor and the conductance box were connected with N type coaxial connector and adapters to ensure a very stable and reproducible value for the stray capacitance C4 Two adapters were in fact needed a GR874 N adapter and an N N adapter The combined stray VIII Semetro Jo o Pessoa PB Brazil June 17 19 2009 ground capacitance value C4 which includes both the internal ground capacitance of the standard capacitor C4 66 4 pF and that for the conductance box C4 11 7 pF was determined with a commercial low frequency impedance analyzer to be 78 4 pF Table I lists the standard uncertainties associated with the dissipation factor that can be obtained with this method As Stated in the introduction this method has some shortcomings a high voltage apparatus is required the number of test points is restricted to the number and values of the standards available and the dissipation factor uncertainty increases with the actual dissipation factor being measured this is due to the uncertainty contribution associated with the measurement of the combined stray junction capacitance to ground C34 TABLEI DISSIPATION FACTOR Nominal u Dy Dissip Factor k 1 5 10 0 000003 2 10 0 000003 AO 0 000005 2 10 0 000043 1 107 0 00025 O Cx Cs 1 1 The operating principle of a new approach designed to overcome those problems is det
24. Thomas type resistors in Fig 1 1883409 shows very significant changes in Table 1 after cycling to 20 C while the other resistor shows much smaller effects Table 1 Resistance changes measured at 25 000C after temperature cycling with temperature characterization results for Thomas type resistors Relative standard uncertainties k 1 are 0 005 uQ 0 for the changes in resistance 0 0064 uQ 0 C for first order coefficient a and 0 0010 UAY for second order coefficient B Data was analyzed using Eq 1 with T 25 000 C Resistor Cycled Cycled Coefficient Coefficient date of measurements The temperature coefficients given in Table 1 were derived from this temperature cycling process using Eq 1 The TCRs of three of the standards were remeasured in 2008 and for two of these standards the coefficients a and B had not changed by more than their measurement uncertainties For most Thomas type resistors and for all NML resistors that have been tested the temperature coefficients remain unchanged over many years Evanohm NML 1 Q resistors in general do not show any significant hysteretic change in resistance in similar temperature cycling tests This may be because the wire is held by flexible fixtures which eliminate strain from thermal cycling Power loading is a change in resistance caused by Joule heating from the measurement current Power loading changes are usually small but can be significant contributions t
25. Trabajo del Uruguay UTU en 2000 En 1978 ingres en el Laboratorio de UTE como t cnico en instrumentaci n Al presente trabaja como especialista en mediciones el ctricas de alta precisi n en ese laboratorio Su rea de actuaci n es mediciones en baja frecuencia donde ha investigado y desarrollado multiples t cnicas de medida Leonardo Montevideo Trigo M 98 naci en Uruguay en 1969 Se gradu de Ingeniero Tecnol gico en Electr nica expedido por Instituto Tecnol gico Superior en 1993 Desde 1994 se desempe a funciones en el Departamento de Electrotecnia Subgerencia Laboratorio UTE Daniel Slomovitz M 86 SM 89 naci en Montevideo Uruguay en 1952 Recibi el t tulo de Ingeniero El ctrico en 1977 y Doctor en Ingenier a en 2000 en la Universidad de la Rep blica Uruguay Act a como Profesor Catedr tico en la misma universidad En 1977 se incorpor al Laboratorio de UTE como Ayudante de Ing ocupando actualmente el cargo de A hs Jefe del Laboratorio Ha llevado a cabo investigaci n en mediciones de baja frecuencia y alto voltaje habiendo publicando m s de 100 trabajos y el libro Mediciones El ctricas del IEEE Alexander M Klushin naci en Gorka USSR el 29 de enero de 1946 Recibi el t tulo de Dial Radio phys y Cand Sci En f sica y matem tica en Gorky State University en 1969 y 1985 respectivamente Ingres en el Institute of Electronic Measurement KVARZ Nizh
26. a ruido electromagn tico se construy un filtro pasa bajas adicional al que incluye el sistema comercial con una frecuencia de corte de alrededor de 1 kHz filtrando el ruido en modo com n y en modo diferencial ver figura 2 El filtro se dise en base a inductores y capacitores para minimizar el error en la tensi n de salida debido al efecto de divisor de tensi n producido por el filtro A 251 mH 4 mH 0 63mH 5 3 H A 0 1 uF 0 01 pF ZZ 0 001 uF 220 0047 pF 0 1 uF 0 01 uF 0 001 pF j 0 0047 uF B 2imH 4mH 0 63 mH 5 3uUH B Chip Josephson gt Fig 2 Circuito el ctrico del filtro adicional El filtro fue dise ado para filtrar el ruido en modo diferencial y en modo com n Cada etapa del filtro se aloja en blindajes independientes para disminuir la interferencia electromagn tica de alta frecuencia La figura 3 muestra la respuesta en frecuencia del filtro adicional descrito Funciones de transferencia del filtro mf Yodo diferencial Ganancia dB fe Modo com n Log f H2 Fig 3 Respuesta en frecuencia del filtro adicional medida en modo com n es decir tomando la entrada en A tierra y la salida en A tierra as como en modo diferencial es decir tomando la entrada en A B y la salida en A B 5 EL SISTEMA DE MICROONDAS El sistema funciona a una frecuencia de alrededor de 75 GHz Como referencia de frecuencia se utiliza un reloj at mico de Ces
27. an annual meeting of SIM EMWG of tutorials on electrical metrology and the participation of fifteen representatives from national metrology institutes of the Americas at the VII International Seminar on Electrical Metrology VIII SEMETRO held from 14 to 19 of June 2009 in the city of Joao Pessoa Paraiba in Brazil The participants and their respective information are the following Participants Institute Email contact Argentina INTI Instituto Nacional Lucas Di Lillo Idili inti gov ar de Tecnologia Industrial Brazil Instituto Nacional de Gregory gakyriazis inmetro gov br Metrologia Kyriazis Normalizac o Qualidade Industrial fF LCPN ME Laboratorio Rodrigo roramos udec cl Custodio Patr n Ramos Nacional de Magnitudes El ctricas LCPN ME Laboratorio Daniel dacarcam udec cl Custodio Patron Carcamo Nacional de Magnitudes Chile Chile El ctricas Colombia SIC Superintendencia Alexander amartinez cotreo sic gov co de Industria y Comercio Martinez Costa Rica ICE Instituto Harold hsanchez ice co cr Costarricense de Sanchez Electricidad Ecuador CMEE Instituto Bolivar bolivaraguilera yahoo com Ecuatoriano Aguilera Normalizacion CONACYT Carlos cartiga conacyt gob sv Laboratorio Nacional de Artiga Metrologia Legal Mexico CENAM Centro David Avil s caviles cenam mx Nacional de Metrologia Panama CENAMEP AIP Centro Julio Gonzalez jgonza
28. and Technology Gaithersburg MD 20899 8171 USA jones nist gov 3 National Measurement Institute Bradfield Road West Lindfield NSW 2070 Australia brian pritchard O measurement gov au Abstract The U S National Institute of Standards and Technology NIST and the National Measurement Institute of Australia NMIA have recently examined two types of precision transportable 1 2 resistors that are based on different alloys and construction principles to determine characteristics that can reduce the uncertainty of international comparisons This work focuses on standards manufactured from 1970 through 2000 by the NMIA and Thomas type resistors designed in the 1930s by James L Thomas and manufactured commercially through about 1980 The effects of temperature barometric pressure humidity power loading and heat dissipation in oil are described in these two types of transportable wire wound 1 Q resistance standards and the process of characterization of these resistors for use as transport standards 1s described Key words electrical resistance standard key comparison temperature coefficient power loading 1 INTRODUCTION International comparisons of dc resistance measurement capabilities are generally based on a small number of transportable resistance standards measured by a sequence of National Measurement Institutes NMIs with intervening periods in which the standards travel between laboratories The results are analyz
29. capacitance Cy and dissipation factor tan dx of a test capacitor at power frequencies Fig 1 Guy HIGH VOLTAGE CAPACITANCE AND DISSIPATION FACTOR BRIDGE Fig 1 Measurement system at high voltage On the high voltage side the standard capacitor and the test capacitor are connected to the high voltage Uyy with amplitude Unvy and phase dy and the low voltage terminals are connected to the inputs Es and Ey of the bridge which are nearly at ground potential The bridge measures the complex ratio of the input currents s and Jx Assuming that lossy capacitors are modeled as a series circuit of reactance 1 wC and loss resistance R where the dissipation factor loss tangent tan 6 D WCR the amplitudes of the input currents are 1 Cy U yy VIII Semetro Jo o Pessoa PB Brazil June 17 19 2009 and the corresponding phases are arg 1 0 7 2 0 2 arg I 0 1 2 0 a From these currents the bridge evaluates the amplitude ratio and the phase displacement Zs Cs Yl tan 3 arg Ix arg I s x Assuming a nondissipative standard capacitor tan s 0 the dissipation factor tan dy and the capacitance Cx of the test capacitor can be calculated directly from the ratio and the phase displacement of the input currents that is tan 6 tan arg I arg I Cy a 1 tan d oe S 3 DISSIPATION FACTOR STANDARDS Dissipation factor standards can also be used to calibrate the d
30. con modelo aprobado En los a os que lleva implementado el acuerdo espec fico se realiz la aprobaci n de modelo de 26 medidores de energ a el ctrica seg n la siguiente distribuci n Monof sico electromec nico Monofasico electr nico Trif sico electromec nico Trif sico electr nico Para el caso de los medidores electromec nicos tanto monof sicos como trif sicos se utilizaba la norma UNE EN 60521 hasta el a o 2006 A partir del a o 2007 ya se realizaron en base a las normas IEC 62052 11 y 60052 21 Para el caso de los medidores electr nicos est ticos tanto monof sicos como trif sicos se VIII Semetro Joao Pessoa PB Brazil June 17 19 2009 utilizaba la norma UNE EN 61036 hasta el a o 2006 A partir del a o 2007 las normas de referencia para estos tipos de medidores ya fueron las normas IEC 62052 11 60052 22 y 60052 23 Es de destacar que en los ltimos 2 a os solamente fueron presentados para ensayos de aprobaci n de modelo medidores del tipo electr nico est ticos lo que se puede inferir como la tendencia a la desaparici n del mercado de los medidores de tipo electomec nico 5 2 Cantidad de medidores con verificaci n primitiva La verificaci n primitiva de medidores se ha realizado hasta la fecha ntegramente en plantas fabriles instaladas en territorio brasile o totalizando 5 f bricas diferentes a la fecha En el siguiente cuadro se detalla la cantidad
31. de medidores de energ a a los cuales se les ha ensayo en verificaci n primitiva Cantidad de medidores 2008 PRI AU E E IA A E 2007 2006 PO OO O O O O E 2004 a O A o 0 10000 20000 30000 40000 50000 60000 70000 80000 90000 La cantidad engloba medidores monof sicos y trif sicos Unicamente en el a o 2 004 se realiz verificaci n primitiva de medidores electr nicos La verificaci n primitiva es realizada por muestreo en base a lo establecido en la Norma UNE EN 60514 para los medidores electromecanicos tanto monof sicos y trif sicos En cambio para el caso de los medidores de energ a electr nicos est ticos trif sicos se ha utilizado como base la norma IEC 1358 Hasta la fecha no se ha realizado la verificaci n primitiva de medidores electr ncios est ticos monof sicos En el siguiente cuadro se pueden observar la cantidad de lotes que tuvieron que pasar a segunda muestra y lotes que fueron reprobados directamente en la primera muestra 20 18 16 4 14 12 Segunda muestra 10 Reprobados 8 6 4 5 E k i 0 2004 2005 2006 2007 2008 Se puede destacar que en los primeros a os de verificaci n primitiva de medidores de energ a los problemas m s comunes y reiterativos se refer an a corriente de arranque y marcha en vac o En a os posteriores se pudo observar una notable mejor a teniendo como referencia que la cantidad de lotes qu
32. de la Protecci n de la Propiedad SNM INDECOPI Peru Henry Postigo Servicio Nacional de Metrolog a Indecopi Per Poster Session W 16h30min 18h00min Instituto Nacional de Tecnolog a Normalizaci n y Metrolog a INTN Paraguay Robert Duarte La metrolog a el ctrica en el INTN Poster Session W 16h30min 18h00min Thursday June 18 Centro Nacional de Metrolog a CENAM Mexico David Avil s et al El patr n de efecto Josephson del CENAM experiencias en 15 a os de uso Session TA1 11h30min Administraci n Nacional de Usinas y Transmisiones El ctricas UTE Uruguay Daniel Slomovitz et al Avances en la implementaci n de un patr n de tensi n por efecto Josephson con superconductores de alta temperatura en UTE Session TA1 11h50min Instituto Nacional de Metrologia Normaliza o e Qualidade Industrial Inmetro Brasil Gregory Kyriazis A New Approach for Calibrating High voltage Capacitance and Dissipation Factor Bridges Session TB1 14h40min Friday June 19 Administraci n Nacional de Usinas y Transmisiones El ctricas UTE Uruguay Daniel Slomovitz et al Control de la deriva en osciladores de rubidio Session FA1 10h50min Instituto Nacional de Tecnolog a Industrial INTI Argentina Lucas Di Lillo et al Sampling wattmeter at INTI Session FB1 14h20min National Research Council Canada NRC Cana
33. de precisi n de medidores est ticos de clase 1 y 2 Las calibraciones que hemos realizado son 663 en el a o 2006 756 en el a o 2007 y 970 al 19 de diciembre de 2008 Tenemos realizadas 71 aprobaciones de modelo de medidores a inducci n clase 2 Actualmente para realizar las calibraciones y el desarrollo del laboratorio se cuenta con tres personas con experiencia en el campo de la metrolog a entre 8 y 26 a os recientemente el grupo de trabajo ha sido incrementado a cuatro lo que permitir realizar mayores desarrollos en el laboratorio de electricidad Otros servicios que ofrecemos son Dictado de cursos sobre calibraci n de medidores de energ a el ctrica a inducci n y est ticos de clase 1 y 2 Recibimos pasantes por periodo de dos semanas para capacitaci n en calibraci n de medidores de energ a el ctrica y patrones de energ a Realizamos comparaciones en energ a el ctrica Este servicio va dirigido a los laboratorios de calibraci n que se est n preparando para su acreditaci n y para empresas contrastadoras que son las que realizan calibraciones ya sea en campo o en laboratorio Las empresas contrastadoras son empresas autorizadas para atender los reclamos de los usuarios de medidores de energ a el ctrica unidades verificadoras Hemos realizado comparaciones en el 2006 2007 y 2008 para medidor de energ a el ctrica est tico monofasico clase 1 de dos y de tres hilos para verificaciones en campo l
34. el INTN se buscaba establecer y ejecutar las etapas de control metrol gico a fin de dar cumplimiento a la Ley de Metrolog a en cambio por la ANDE se buscaba dar una respuesta m s convincente a sus clientes respecto a los inconvenientes y reclamos por supuestas sobrefacturaciones ya que en dichas situaciones la ANDE actuaba como juez y parte y el usuario no ten a posibilidad de acudir a una instancia de tercera parte independiente al conflicto de intereses 4 RESULTADOS ALCANZADOS EN EL A O 2003 4 1 Adquisici n de patrones y equipos auxiliares y preparaci n de local En el a o 2003 se recibieron los siguientes patrones y equipos auxiliares un patr n Zera TPZ 303 0 02 2 equipos trif sicos para verificaci n de medidores en campo Zera TPZ 308 0 1 y 0 2 3 equipos monof sicos para verificaci n de medidores en campo Zera TPZ 108 0 1 y 0 2 y una fuente electr nica estabilizada Zera VCS 320 2 con capacidad de generaci n trif sica y hasta 120 A El patr n Zera TPZ 303 es utilizado conjuntamente con la fuente electr nica son utilizados para la realizaci n de los ensayos de precisi n de los medidores tomando como base las normas IEC aplicables A fin de instalar los equipos se prepar un rea f sica de 20 m donde se realizan todos los ensayos posibles con los equipos disponibles 4 2 Acuerdo ANDE INTN para Aprobaci n de Modelo y Verificaci n Primitiva de Medidores de Energ a el c
35. el software que se ejecuta en el computador La construcci n de este patr n permite seccionar paquetes de junturas de 10 mV por separado o sumarlas hasta llegar a los 100 mV Los paquetes de 10 mV contienen 67 junturas en serie La salida de tensi n seleccionada es medida y comparada contra otros patrones por divisores de tensi n y un mult metro digital de alta impedancia y resoluci n Dado que la tensi n de salida es relativamente peque a se requiere de divisores de tensi n para comparar contra fuentes patrones de 1 Vo 10 V Para esto se desarroll un divisor resistivo de muy alta estabilidad autocalibrable que relaciona estos niveles de tensi n 2 2 EFECTO JOSEPHSON Las junturas Josephson son utilizadas en metrolog a como est ndares de voltaje el concepto se basa en la interacci n entre una microonda externa aplicada a una juntura que da lugar a una ca da de voltaje fundamental exacta a trav s de la juntura La tensi n total en el chip vale Uy Nf IK v 1 siendo N el n mero de junturas fla frecuencia y _2e 90 2 e es la carga del electr n y h la constante de Planck El efecto esta basado en el conocido efecto t nel el que consiste en el pasaje de corriente el ctrica a trav s de una barrera aislante Desde el punto de vista cl sico esto no ser a posible pero la mec nica cu ntica predice que si la barrera es fina la posibilidad que los portadores de carga la atraviesen no es nula Se obs
36. has participated in the CCEM K6 c Key Comparison of RF DC Transfer Standards Results of this comparison have fully confirmed validity of the evaluation of CTVC frequency characteristic and its uncertainty budget 7 The CTVC can be also used in the current mode for the current AC DC Difference frequency range extension We used a MJTC as well as a Fast Reversed DC Source to characterize the CTVC in the current mode at low frequency On the basis of these measurements we have assigned the value of 0 0 0 8 uA A to the AC DC current transfer difference of a CTVC in the frequency range of 10 Hz 100 kHz 8 Starting from the CTVC used as a standard of a current AC DC transfer difference and following a build up procedure we were able to extend NRC AC DC capabilities to currents as high as 100 A at 100 kHz 600 400 z 200 LLI O 0 LLI E 200 LL e Calculated frequency characteristic Le o Measured frequency characteristic CTVC A A 400 v Measured frequency characteristic CTVC B 5 A Measured frequency characteristic CTVC C 600 lt 800 1000 101 100 10 102 103 104 105 FREQUENCY kHz Fig 3 Calculated and measured frequency characteristic for three different realizations of a CTVC Error bars show estimated expanded uncertainty k 2 VIII Semetro Jo o Pessoa PB Brazil June 17 19 2009 The CTVC is small easily transportable and mechanically stable We h
37. laboratories difference values can be accurately corrected for the characteristics of the standards 2 TYPES OF RESISTOR The Asia Pacific Metrology Program APMP performed the 1993 1994 APMP EM K1 comparison 1 which employed three 1 Q resistance standards manufactured by the Australian National Measurement Laboratory NML now the NMIA These standards were made from the resistance alloy Evanohm and were produced first in the 1970s and redesigned in the early 1990s specifically to improve transportability In the Inter American Metrology System SIM the SIM EM K1 comparison of 2006 2007 2 employed three Thomas type resistors an older but equally important class of resistor because of its wide use as a primary standard in many NMIs in all parts of the world The paper will describe these 1 Q resistance standards and compare their measurement properties including the characteristics and influences likely to effect transport behavior These results help to build and clarify selection and measurement criteria for these types of resistors The NML 1 Q resistor is formed by a partially self supporting 2 1 mm diameter Evanohm wire wound as a bifilar coil The metal case allows mineral oil in which the resistor is immersed to flow over the wire so as to maintain the wire at a constant temperature The resistors constructed at the NML have very low temperature coefficients of resistance TCRs and are extremely stable mechanica
38. lo cual se constituye en una entidad capaz de brindar un servicio integral confiable y eficaz de aseguramiento metrol gico para la industria la ciencia y el comercio NACIONAL DE El SNM cuenta con la cooperaci n t cnica de organismos metrol gicos internacionales de alto prestigio tales como el Physikalisch Technische Bundesanstalt PTB de Alemania el Centro Nacional de Metrologia CENAM de Mexico el National Institute of Standards and Technology NIST de USA el Centro Espanol de Metrologia CEM de Espana el Instituto Nacional de Tecnologia Industrial INTI de Argentina el Instituto Nacional de Metrologia INMETRO de Brasil entre otros Dentro de las funciones del SNM tenemos custodia y ampliacion de la coleccion de patrones nacionales calibrar patrones secundarios realizaci n de afericiones y calibraciones de instrumentos emisi n de certificados de calibraci n y de conformidad de productos con respecto a normas de car cter metrol gico aprobaci n de modelo a solicitud del usuario Para cumplir con la tarea encomendada el SNM cuenta con ocho laboratorios base que son Laboratorio de Masa LM y Grandes Masas Laboratorio de Temperatura LT Laboratorio de Electricidad LE Laboratorio de Longitud y Angulos LLA Laboratorio de Fuerza y Presi n LFP Laboratorio de Volumen y Densidad y Flujo LVD Laboratorio de Metrolog a Qu mica LMQ y Laboratorio de Ac stica LAC Los Laboratorios de
39. mediciones est n basados bajo la asunci n de que las fuentes de voltajes son puramente sinusoidales y que las cargas son lineales por lo tanto la corriente tambi n es sinusoidal El incremento en la demanda y la no linealidad en la cargas son m s comunes hoy en d as como consecuencia la aproximaci n sinusoidal no es v lida para todas las situaciones El sistema de medici n que conforma nuestro patr n de potencia el ctrica esta constituido por los siguientes elementos VIII Semetro Joao Pessoa PB Brasil Junio 17 19 2009 e Fuente de alimentaci n e Divisor inductivo de tensi n e Convertidor de corriente a tensi n con resistencia patr n compensada t rmicamente e incluida e Dos mult metros Agilent 3458A e Computadora Para verificar un sistema de medici n de potencia el ctrica y hacer mediciones precisas en situaciones no sinusoidales se requiere de una compensaci n de los mecanismos de error El sistema de medici n de potencia que ostenta nuestro patr n utiliza para dicha compensaci n el algoritmo de Swerlein el cual corrige los errores introducidos por los mult metros digitales 3458A El esquema de nuestro sistema de medici n se muestra en la Fig 1 y lo podemos describir de la siguiente forma Una fuente genera determinados valores de tensi n y corriente alterna las se ales de tensi n e intensidad son llevadas a un nivel de tensi n correspondiente al rango de 10V de los mult metros digitales
40. multiplication of such experience in their countries through national meetings seminars and other internal activities I would like to thank all members of the Organizing Committee of VIII SEMETRO I thank Gelson Rocha co chairman of the Organizing Committee for his support Melissa dos Santos Galdino did a nice job in organizing the tutorial notes and the training activity I am also grateful to the personnel from Sociedade Brasileira de Metrologia SBM Pedro Paulo Rosario Leticia Barbosa and Monica Costa I thank the contribution of several others that I do not mention sorry for that who indirectly contributed to this school I would like also to thank the support provided by Prof Humberto Siqueira Brandi director for Scientific and Industrial Metrology of Inmetro and president of SIM and Taynah Lopes de Souza SIM secretariat who kindly managed the financial resources for the project I am also grateful to Prof Raimundo Carlos Silverio Freire UFCG chairman of VIII SEMETRO and Sebastian Yuri Cavalcanti Catunda UFMA co chairman of the Organizing Committee for their collaboration And last but surely not the least I wish to thank Prof Jo o Alziro Herz da Jornada president of Inmetro for all his support in the realization of the VIII SEMETRO and the SIM T amp D on Electrical Metrology This training activity has been funded by the Perez Guerrero Trust Fund for Economic and Technical Cooperation among Developing Countries PGTF
41. nA or two parts in 10 of the test current 0 02 mA The lower the resistor values are the more precise they should be to impedance Z4 nickel coated metal box to bridge input Eo Fig 4 Amplifier circuit Aj The resistor and amplifier boxes have a coaxial design Fig 5 Both are nickel coated to reduce the contact resistances The output voltages of the signal generators are sampled by the digital voltmeters through the connectors on top of the resistor boxes This is done to avoid the voltage drops in the output leads of the signal generators Fig 5 Amplifier boxes left and resistor boxes right We have recently verified that sometimes the bridge under calibration became damaged immediately after conducting the test An investigation has been made to solve the problem It was found that the cause was an unbalance in the outputs of the Vcc and the Vcc voltage regulators that feed the operational amplifier The solution was to insert a parallel RC circuit between those outputs as illustrated in Fig 6 The scheme also shows the means used to switch off the circuit and to allow the batteries to be loaded We chose the operational amplifier OPO7 for its accuracy and stability combined with its freedom from external offset nulling The stability of offsets and gain with time and variations in temperature of such amplifier is excellent 7 MEASUREMENT UNCERTAINTY Commercial electronic bridges based on 1 2 have b
42. que con el chip PREMA tuvimos mayores problemas de flujo atrapado al enfriarlo este problema se resolvi cambiando la t cnica de enfriamiento del chip como se describe en la secci n 6 3 MODIFICACIONES A LA FUENTE DE POLARIZACION Cuando se usa el patr n para calibrar una fuente de tensi n el patr n genera una tensi n cercana a la de la fuente y se mide la diferencia con un detector de nulos Para eliminar las fems t rmicas del circuito de medici n y el offset del detector de nulos se utiliza la t cnica de cambio de polaridad Para que esta t cnica funcione de manera ptima se requiere tener nulos muy peque os en ambas polaridades en la fuente comercial era necesario ajustar la tensi n de polarizaci n cada vez que se cambiaba la polaridad para tener el mismo nivel cu ntico en ambas polaridades ya que la tensi n de polarizaci n era un poco diferente en una polaridad en relaci n con la otra Para evitar este ajuste que hace lenta la operaci n del patr n e incrementa las incertidumbres por fems t rmicas no compensadas se modific el circuito introduciendo la posibilidad de a adir un offset ajustable en una de las polaridades tal que permite que cuando se cambia la polaridad del patr n autom ticamente se tiene el mismo nivel de tensi n que en la polaridad contraria En algunas aplicaciones como la comparaci n directa de patrones Josephson es importante poder seleccionar un escal n cu ntico en partic
43. referencia las normas lEC aplicables como 4 3 Capacitaci n de t cnicos En setiembre de 2003 el INTN env a dos t cnicos al INTI Buenos Aires Argentina para capacitaci n en las futuras actividades a ser desarrolladas en el marco del Convenio con la ANDE La capacitaci n de los t cnicos tuvo una duraci n de cuatro semanas centradas espec ficamente en participaci n en todos los ensayos de aprobaci n de modelo de medidores de energ a el ctrica activa y reactiva est ticos electr nicos y electromec nicos Adem s se participa en la calibraci n de mesas de verificaci n de medidores de energ a el ctrica instaladas en las distribuidoras de energ a el ctrica de la ciudad de Buenos Aires Argentina Posteriormente se recibe en INTN una capacitaci n dada por el fabricante de patrones de medici n Zera fabricante del cual se hab an adquirido la mayor a de los equipos y patrones para el desarrollo y ejecuci n de los diversos ensayos Dicha capacitaci n dur dos semanas y se focaliz en la pr ctica de los procesos de medici n posibles de ejecuci n con los nuevos equipos asi como la elaboraci n de tablas automatizadas para la ejecuci n secuencial de ensayos a los diferentes tipos de medidores de manera a lograr un mejor aprovechamiento de las capacidades de medici n y calibraci n 5 RESUMEN Y RESULTADOS DE LOS CONTROLES IMPLEMENTADOS DESDE EL A O 2004 AL A O 2008 5 1 Cantidad de medidores
44. resistors Laboratory requirements such as measurement systems and environmental controls Scaling techniques suitable for different resistance levels Uncertainty budgets and types of uncertainty basic statistical concepts control charts and prediction of drift in working standards June 16 morning P Filipski NRC AC DC Thermal Transfer Standards and Calibrations Language English This tutorial will concentrate on the practice of the ac dc transfer measurements After a short but necessary theoretical introduction practical aspects of the ac dc voltage and current transfer will be discussed The topics will include Primary and secondary standards used by the leading laboratories Practical construction of an ac dc transfer comparator Extensions of voltage and current ranges Extension of the operating frequency ranges Practice of routine measurements and calibrations Typical components of uncertainty If time permits some more exotic techniques such as fast reverse dc measurements and ac Josephson voltage standards ACJVS will also be introduced June 16 afternoon D Slomovitz UTE Power and Energy Measurements Language Spanish This tutorial will concentrate on the general theory on high precision power measurements at national and secondary calibration laboratories However some time will be used to discuss the performanc
45. s world Rapport BIPM 94 5 May 1994 ViitSemetrO CALIBRACION DE CRONOMETROS MEDIANTE LA MEDICION DE LA FRECUENCIA DEL OSCILADOR DE CUARZO Johnny Jim nez Harold S nchez Instituto Tecnol gico de Costa Rica ITCR Cartago Costa Rica jojimenez84 gmail com Instituto Costarricense de Electricidad ICE San Jos Costa Rica hsanchez ice go cr Resumen Se presenta un sistema de medici n de La frecuencia b sica del oscilador de cuarzo de cron metros para la automatizaci n de la calibraci n El sistema detecta la se al b sica de oscilaci n del cristal de cuarzo 2 Hz mediante la inducci n de una corriente en placas paralelas usando el efecto capacitivo y procesando la se al para extraer la frecuencia b sica dentro de una se al muy ruidosa Con este m todo se reduce significativamente la incertidumbre de calibraci n comparada con el m todo de comparaci n de la lectura en pantalla Tambi n se reduce el tiempo del proceso calibraci n Palabras clave calibraci n cuarzo relojes cron metros 1 INTRODUCCI N La calibraci n de cron metros se ha estado realizando en el Laboratorio Metrol gico del Instituto Costarricense de Electricidad mediante el m todo de lectura de la pantalla y comparaci n con la lectura de un receptor GPS Este m todo introduce dos factores importantes de incertidumbre por la resoluci n del cron metro y por la reacci n manual del metr logo En otros labora
46. sampling wattmeter is 25uW VA The main component is the thermal dependence of the ac dc shunt Table 3 Differences between power thermal converter and sampling wattmeter in uW VA Differences between power thermal converter and sampling wattmeter in uW VA 4 FUTURE WORK In order to reduce the uncertainty due to the thermal dependence of the shunt a new series of shunts of 5 A and 1 A are under development Together with the shunts a resistive divider will be used to measure power harmonics Also new measurements at 50 Hz will be done with the current transformer 5 CONCLUSIONS A new sampling wattmeter was built at INTI Comparisons between the new system and the thermal power comparator show a promising agreement within the uncertainties REFERENCES 1 G Schuster Thermal measurement of ac power in comparison with the electrodynamic method IEEE Trans Instrum Meas vol IM 25 pp 529 533 Dec 1976 2 H Laiz y R Garcia A Power Comparator with High Accuracy Simple and Inexpensive IEEE IEEE Trans on Instrum Meas vol 46 No 2 pp 407 410 April 1997 3 N Oldham et al An International Comparison of 50 60 Hz Power 1996 1999 IEEE IEEE Trans on Instrum Meas vol 49 No 2 April 2001 4 G Kyriazis A de Campos M L R An algorithm for accurately estimating the harmonic magnitudes and phase shifts of periodic signals with asynchronous sampling IEEE IEEE Trans on Instru
47. to 100 MHz and above less accurate at low frequencies but simpler to evaluate at RF UHF type single junction Thermal Voltage Converters TVCs and calculable coaxial resistors are used as standards by most National Metrology Institutes 1 2 A planar MJTC on a quartz crystal chip is also considered as a possible RF standard 3 At NRC a reference standard of the RF DC transfer difference in the frequency band above the MJTC range is a Calorimetric Thermal Voltage Converter CTVC 4 5 The mechanical and electrical design of the CTVC is straightforward permitting for theoretical calculations of its VIII Semetro Jo o Pessoa PB Brazil June 17 19 2009 frequency characteristic It is based on a design of a microwave calorimeter Its AC DC voltage transfer difference is low usually below 3 uV V but not negligible However the CTVC AC DC transfer characteristic is flat in the eight decades of frequency from 1 Hz to 100 MHz its typical input voltage range is from 1 V to 2 V 2 DESCRIPTION OF DESIGN During an AC DC transfer voltage calibration of a thermal converter the tested and reference converters are connected in parallel attached to two arms of a coaxial tee adapter The calibration voltage reference plane is in the middle of the tee The length of the coaxial arm of the tee as well as the matching connector becomes an integral part of each converter Thus the design of a reference converter with a
48. to be caused by strain induced in the resistance element by unequal thermal expansion coefficients of the resistor wire element and its support The long term effect of this strain is a semi permanent or hysteretic change in the resistance value These two resistors are affected strongly by hysteresis and have greater long term instability than most Although the magnitudes of the changes in resistance at 25 C differ Thomas type resistors in general tend to increase in resistance after being subjected to temperatures above 25 C and decrease in resistance after being subjected to temperatures below 25 C The data show that the change in resistance value tends to relax partially with a time constant of two to three days The complete process of relaxation can continue for much longer periods and can result in changes in drift rates that last many months for some Thomas type resistors Table 1 shows the magnitudes of hysteretic change in resistance for smaller temperature changes up to 5 C a range that is more normal for characterization of Thomas type resistors The values were measured as the temperature was changed to 23 C and 20 C for one week periods Before and after each temperature cycle the resistance was measured for at least a week at the normal maintenance temperature of 25 C Among these seven Thomas type resistors are two resistors that were subjected to the larger temperature changes shown in Fig 1 One of the two
49. using Swerlein s algorithm 6 and the samples are stored in a PC To calculate harmonic power we used an algorithm developed by Pogliano 7 2 1 SAMPLING SYSTEM The core of the wattmeter is the sampling system We use asynchronous sampling because the sampling frequency is not locked to the source frequency by hardware We use two digital multimeter DMM Agilent 3458A in a master slave configuration Therefore each time one DMM Master takes a measurement it send a pulse to the second one Slave to keep phase timing This can be done using a cable connection between the trig out terminal of the Master DMM and the trig in terminal in the slave DMM For the measurement and processing the signal we combined two methods To obtain the samples parameters for the current and voltage signals we use the well know Swerlein s algorithm 6 The advantage of use Swelein s algorithm is that it reduces the error in the root mean square RMS value by choosing the adequate sampling parameters In our case we are sampling two signals voltage signal has an rms value of 6 V corresponding to the voltage output of the VT and the other one has an rms value of 1 V corresponding to the voltage drop in the resistor of 10 2 In order to avoid phase errors the delay between the two DMM must be measure and then corrected In our case the time delay is aprox 500 ns and it depends on the cable length used to synchronize the two DMMs
50. yi sinh 7 2 l where y is the propagation constant Z is the characteristic impedance of the lossy coaxial line and Z is the impedance of the heater Details of the calculations of the propagation constant and the characteristic impedance of the CTVC are given in references 4 and 5 Here it should be noted that the miniature heater is modeled as a non reactive resistor and that in calculating the coaxial line parameters the skin effect is taken into account We have measured the skin effect surface resistance of type N connector tested converter Thermopile Bendix connector de millivoltmeter Fig 2 Simplified diagram of the calorimetric thermal voltage converter VIII Semetro Jo o Pessoa PB Brazil June 17 19 2009 the stainless tubing experimentally on open circuited resonant coaxial lines made of long lengths of the inner and outer conductors used in the construction of the CT VC The temperature rise of the heater is due not only to the energy dissipated directly in the heater but also to the energy dissipated in the lossy coaxial line connected to the heater This effect was taken into consideration by introducing a thermal correction 4 The CTVC is mechanically and electrically stable and not easily damaged by overloading However it is relatively more difficult to measure than a regular TVC due to its small output voltage 4 5 mV a
51. 4 7 1 0 00015 8 1 0 00011 9 1 0 00012 10 1 0 00023 Dx 1 10 and l s 0 02 mA TABLE VI DISSIPATION FACTOR Nominal U Dxsef Dissip Factor k 1 1 10 0 000005 1 10 0 000005 1 10 0 000005 1 107 0 000005 1 10 0 000004 1 107 0 000006 Cy Cs 1 1 and Ul 0 02 mA TABLE VII CAPACITANCE RATIO Nominal CdCI Cap Ratio k 1 10 1 0 000084 20 1 0 00015 30 1 0 00026 40 1 0 00054 50 1 0 00045 60 1 0 00085 70 1 0 00054 80 1 0 00097 90 1 0 0015 100 1 0 0021 Dx 1 10 and l s 0 02 mA 8 EXPERIMENTAL RESULTS Examples of simulated reference values of capacitance ratio and dissipation factor at Z 0 2 mA and the corresponding average readings of the bridge based on 1 are listed in Table VIII and Table IX respectively Tables X and XI list the figures obtained for the bridge based on 2 which has a resolution of 1 10 for both capacitance ratio and dissipation factor measurements Table XII shows the results obtained for capacitance ratios from 10 1 to 100 1 for the bridge based on 2 The tables also list the expanded uncertainties k 2 associated with the reference values The differences between the reference values and the average readings are in general well within those expanded uncertainties The differences for high values of dissipation factor actually exceed the expanded uncertainties but the manufacturers do recognize this by suitably decreasing the accuracy claims for such values in
52. April 2001 5 D Hern ndez E Navarrete D Avil s Y Tang Final Report Bilateral Comparison of DC Voltage References between CENAM and NIST SIM EM BIPM K11 b Metrologia 44 Technical Supplement Technical Supplement 2007 01011 15V 0 1 uF Relaci n 50 Q 3009 CLC430_ E 500 z Contador O EIP 578 B O O 680 Q Fig 4 Amplificador para la referencia de frecuencia de 10 MHz VIII Semetro Jo o Pessoa PB Brazil June 17 19 2009 VIIHSemetrO AVANCES EN LA IMPLEMENTACI N DE UN PATR N DE TENSI N POR EFECTO JOSEPHSON CON SUPERCONDUCTORES DE ALTAS TEMPERATURAS EN UTE Heriguat de Souza Leonardo Trigo Daniel Slomovitz Alexander Klushin 1 LABORATORIO de UTE Montevideo Uruguay hdesouza O ute com uy 2 Institut fur Schishten und Grenzflashen Germany a klushin fz juelish de Resumen Este art culo tiene como finalidad difundir los resultados obtenidos en el desarrollo de un patr n de tensi n utilizando superconductores de alta temperatura YBCO Estos superconductores trabajan a temperatura del nitr geno l quido el cual tiene un costo muy reducido y es de f cil adquisici n El desarrollo de este patr n usa un integrado superconductor el cual consta de varias junturas Josephson conectadas en serie a las cuales se puede acceder y seleccionar de acuerdo al nivel de tensi n requerido en la salida desde 10mV a 100mV Palabras clave Patrones de tensi n efecto Josephson supercon
53. CIPANTES gt gt 7 PARTICIPANTES contrastadoras La segunda comparacion se realiz en el a o 2007 en la que hubo cinco participantes cuatro fueron empresas contrastadoras y uno fue una empresa en v as de autorizaci n el participante Fig 2 Carga nominal 2006 Fig 5 Carga nominal 2007 identificado con el n mero 5 no present sus resultados a tiempo lo que no permiti incluirlo en el informe final Tres empresas COMPARACION EN CARGA MAXIMA l 60 A F P 1 2006 COMPARACION EN CARGA MAXIMA I 60 A F P 1 2007 contrastadoras participaron tanto en la M comparaci n del 2006 como en la del 2007 05 con el fin de facilitar la comparaci n y T lt evaluaci n correspondiente de las figuras del i ii 1 al 6 se ha identificado a los participantes de la siguiente manera N D 2 A D g S N D PARTICIPANTE PARTICIPANTE Fig 3 Carga m xima 2006 Fig 6 Carga m xima 2007 g Participante Participante Participante ANO 0 rojo o amarillo 3 azul 2 Comparaci n de medidor de energ a el ctrica est tico monof sico de tres hilos clase 1 Para esta comparaci n se emple un medidor monof sico est tico de tres hilos clase 1 constante 1600 imp kWh 220 V 10 A 50 A para una frecuencia de 60 Hz ee IE e 2006 2007 Nota El cuarto participante fue distinto en cada a o Seguido se muestran las figuras del 1 al 6 correspondiente a l
54. Ceremony 00min Conference Dinner 21h Commitment fee applicable 00min 22h D0min Technical Papers The participants were stimulated to present technical papers during the conference The technical papers were printed and brochures containing all papers were distributed to all participants The brochure was prefaced as follows It is indeed an honor and a privilege for us to welcome you who are participating in the SIM Training and Development on Electrical Metrology in Joao Pessoa PB Brazil from 15 to 16 June 2009 The main objective of the SIM T amp D on Electrical Metrology is the training and capacity building of metrologists from all the Americas in the field of electrical metrology For that it has been envisaged the organization of tutorials on electrical metrology and the concomitant realization of the VIII International Seminar on Electrical Metrology VIII SEMETRO June 17 19 2009 The tutorial concentration will be on measurements related to the following dc low frequency electrical quantities dc voltage ac dc voltage and current transfer dc resistance and power and energy It is expected that the tutorials will promote the development of electrical metrology activities within the region increasing the recognition and reliability of calibration and measurement services that support international trade For that the methodology proposed comprises besides the exchange of experience among participants the
55. Damel Slomovitz NIST UTE Note 1 We recommend the reader to consult the detailed techuical programme for further information Note 2 The titles of the talks are prelimunary and are subject to change Version 2008 12 01 II 1 Tutorials on electrical metrology The themes of the tutorials were concentrated on measurements related to the following dc low frequency electrical quantities a DC voltage b AC DC voltage and current transfer c DC resistance d Power and energy The tutorials promoted the strengthening of electrical metrology activities within the region increasing the recognition and reliability of metrological services that support international trade For that the methodology proposed consisted of besides the exchange of experience among participants the multiplication of such experience in their countries through national meetings seminars and other internal activities The experts who were invited to provide lectures to the participants are described below Lecturers Carlos Avil s Centro Nacional de Metrolog a Santiago de Quer taro Mexico David Aviles was born in Mexico City M xico in 1961 He received the DEA degree and the Ph D degree in Instrumentation and Measurements from the University of Bordeaux I France He was the Head of the Electromagnetic Measurement Division of CENAM from 1992 to 1998 since 1998 he has been Scientific Coordinator of the Quantum Standards Group of the Electromagnetic Me
56. IST 4 En 2006 se particip en una comparaci n bilateral con NIST la comparaci n se hizo en el CENAM midiendo 4 referencias Zener con el patr n Josephson de CENAM y el patr n Josephson transportable de NIST con esto se eliminaron los efectos de deriva y las correcciones por presi n atmosf rica con lo que fue posible reducir la incertidumbre de la comparaci n a 43 nV k 2 5 AGRADECIMEINTOS Los autores agradecen a nuestros compa eros M en C Jorge Blancas y al Ing Mario Alatorre por el dise o y construcci n del amplificador de 10 MHz REFERENCIAS BIBLIOGR FICAS 1 C A Hamilton C J Burroughs and C Kao Operation of NIST Josephson Array Voltage Standard J Res Natl Inst Stand Technol Vol 95 pp 219 235 1990 15V 0 lu Entrada Cabl ial e q able coaxia 500 CLC430_ Reloj At mico 10 MHz C 220 pF E R 82 Q R 680Q 2 E Navarrete D Hern ndez D Avil s Estimaci n de la Incertidumbre del Patr n Nacional de Tensi n El ctrica en Corriente Continua Basado en el Efecto Josephson Simposio de Metrolog a 25 27 de Octubre de 2005 3 C M Wang and C A Hamilton The Fourth Interlaboratory comparison of 10 V Josephson Voltage Standards in North America Metrologia Vol 35 pp 33 40 1998 4 D Deaver W B Miller L Pardo K Jaeger D Plowman and C A Hamilton Interlaboratory Comparison of Voltage Standards IEEE Trans on Instrumentation and Measurement Vol 50 No 2
57. PEREZ GUERRERO TRUST FUND FOR ECONOMIC AND TECHNICAL COOPERATION AMONG DEVELOPING COUNTRIES MEMBERS OF THE GROUP OF 77 GOVERNMENT OF BRAZIL SIM EMWG Training and Development FINAL REPORT 2009 2011 Head of the Project Dr Gregory Kyriazis Inmetro MDIC SIM Training and Development on Electrical Metrology Introduction About half of all manufactured products in the world 1s accounted for by individual items such as aircraft motor vehicles and computers together with their component parts The other half mostly comprises goods manufactured in bulk Of this about half is in the automobile industry other important sectors being aerospace and instrumentation For most of these products their performance and perceived quality and hence their commercial success is determined by how well they are made Electrical technology is increasingly being used in manufactured products The performance of such products is therefore often evaluated by measuring to what extent the electrical quantities depart from specifications The field of electrical metrology 1s also important in the performance evaluation of the electrical power transmission and distribution network of each country Several electrical quantities need to be measured traceably to generate and distribute electrical power safely economically and attending quality requirements International telecommunication systems work reliably and efficiently but for high rates of data transmission ti
58. Transfer Standards and Calibrations Piotr Filipski tutorial notes with 128 pages in color Module 4 Medida de potencia e energ a Daniel Slomovitz tutorial notes with 41 pages in color The CD Mediciones El ctricas authored by Daniel Slomovitz and marketed by the Institute of Electrical and Electronics Engineers IEEE was also distributed to participants in this module The technical program of the tutorials 1s described in the next table Technical Program SIM Training and Development on Electrical Metrology June 2009 Item Date Description Notes l June 15 High accuracy Contents morning DC Voltage Measurements DC voltage traceability C Avil s Standard based on Josephson effect Language Zener references CENAM Spanish Scaling methods High accuracy multimeters and calibrators June 15 afternoon R Elmquist NIST DC Resistance Measurements Language English This workshop will describe de resistance measurement practices suitable for maintaining traceability in National Measurement Institutes of the SIM region The basic precepts are that the laboratory obtains traceability through transfers of standard resistors at key levels maintains and scales the resistance unit to working standards maintains check standards and calibrates customer standards with appropriate uncertainties Topics that are covered include Types and properties of standard
59. ailed in the next section 4 OPERATING PRINCIPLE The new measurement system for the calibration of high voltage capacitance and dissipation factor bridges is depicted in Fig 3 The output voltages of two synchronized programmable signal generators GEN1 and GEN2 11 are applied to the inputs Es and Ex of the bridge under test via two calibrated resistors with impedances Z and Z with ac resistances Z and Z and phase angles arg Z and arg Zp respectively Two high resolution integrating digital sampling voltmeters in a master slave configuration 12 DVM1 master and DVM2 slave are used to measure the voltages V and V with amplitudes Y and Y and phases arg V and arg V gt respectively applied to both the resistors and the current comparator ratio windings N and N2 The errors caused by the impedances of N and N and interconnecting leads are automatically corrected with amplifier circuits A and A respectively that provide the error currents see section 6 for construction details The two DVMs controlled by the algorithm in 6 can measure the amplitude ratio IV VV and the phase displacement arg V arg V of the two output voltage signals with an uncertainty of a few parts in 10 and a few microradians respectively The amplitude ratio and the phase displacement of the input currents are therefore AAA Zs Y Z 7 arg 1 arg 1 argV argV argZ argZ
60. alizations Mechanical assembly uncertainty was evaluated by comparing characteristic of a converter before and after reassembly Uncertainty of the mechanical position of the reference plane was evaluated by building a two port test fixture Fig 3 Calorimetric thermal voltage converter during and after the final assembly identical to the CTVC on the type N connector side but with a SMA type connector terminating the coaxial line The electrical length of the N type side arm was then compared on a Vector Network Analyzer to the electrical length of one arm of a type N Tee 6 The CTVC is not a calculable standard of AC DC transfer difference The theoretical determination of the CTVC characteristic takes into account only frequency dependent parameters Thermoelectric effects are not considered The frequency independent low frequency AC DC transfer difference of a CTVC O 7yc 0 has to be determined experimentally by comparison to a MJTC an AC DC transfer standard calculable at low frequency The AC DC transfer difference of the CTVC was then obtained as the sum of two parts Ocrvc 0 crvck0 Ocrvc f 3 Starting from this standard with the AC DC transfer difference determined at 2 V and frequencies up to 100 MHz the NRC AC DC voltage transfer capabilities are extended to higher and lower voltages by following build up and step down procedures using auxiliary standards and the RF DC Transfer Comparator NRC
61. asurements Division of CENAM He 1s specialized in DC voltage measurements He is involved in the Programmable Josephson Voltage Standard and in the AC Josephson Voltage Standard projects at CENAM Rand Elmquist National Institute of Standards and Technology NIST Gaithersburg USA In 1986 Randolph E Elmquist joined the National Institute of Standards and Technology in Gaithersburg MD where he has contributed to absolute measurements of the Watt and the Ohm His work in these areas has included the development of improved calculable coaxial resistors and cryogenic current comparators He has been involved in international activities through the Inter American System of Metrology SIM and has helped to develop information technology tools for NIST where he leads the Metrology of the Ohm Project Peter Filipski National Research Council NRC Ottawa Canada Piotr Peter S Filtpski is a Senior Research Officer in the Institute for the National Measurement Standards National Research Council Canada NRC He received the M S and Ph D degrees in electrical engineering from the Silesian Technical University STU Gliwice Poland in 1972 and 1977 respectively From 1971 to 1981 he was with STU In 1981 he joined the staff of the Power Engineering Section of the NRC Electrical Engineering Division where he was involved in development of measurement techniques and instrumentation for measurement of active and reactive power particularl
62. at of the reference resistors which are measured at NIST at 25 C In order to measure the pressure coefficient a pressure chamber is used in which three precision resistors can be placed The chamber is partially filled with oil and submerged in another oil bath where the temperature is again maintained at 25 C The chamber s internal pressure is stable and can be increased or decreased in the range of 70 kPa to 110 kPa So far twelve Thomas type Manganin resistors and eight NML Evanohm resistors have been characterized Figure 1 shows the results of tests on two Thomas type resistors when the storage temperature of the resistor is caused to vary by 5 C to 13 C and 5 C to 7 C from the normal maintenance temperature For these two Thomas type resistors the measured resistance values at 25 C are not stable after the periods at higher and lower temperature and do not return to their pre test level 0 3 0 25 0 2 0 15 0 1 0 05 0 05 Relative Change in Resistance from Initial Average Value at 25 C O O e 1883403 41883409 0 1 0 20 40 60 80 100 Time d Fig 1 Values of two Thomas type resistors at 25 C with repeated soaking for 48 h intervals at the temperatures shown The soaking may simulate temperature changes in transport The values have a standard uncertainty k 1 of 0 005 uQ O and are normalized to an average starting value of zero The unstable behavior observed in Fig 1 is thought
63. atrapado 7 INCERTIDUMBRE DEL PATR N DE TENSI N JOSEPHSON DEL CENAM Tabla 1 Fuentes de incertidumbres del Patr n Fuentes de incertidumbre Corrientes de fuga Fems t rmicas no compensadas error del detector de nulos La principal fuente de incertidumbre del patr n es la proveniente de las fems t rmicas no compensadas que ocurren cundo lo operaci n del patr n es lenta y las fems t rmicas no son bien compensadas debido a que cambian durante las mediciones por cambios de temperatura en el sistema de medici n La estimaci n de la incertidumbre del patr n Josephson se describe en detalle en la referencia 2 i 7 Incertidumbre estandar combinada 8 COMPARACIONES INTERNACIONALES Tabla 2 Resultados en comparaciones internacionales a nivel de 10 V Diferencia Incertidumbre expandida k 2 ILC NCSL 1996 ILC NCSL 1999 gt Bilateral 2006 En 1996 se particip en una comparaci n bilateral de patrones de efecto Josephson a nivel de 10 V entre NIST y CENAM dentro del marco de la International Laboratory Comparison ILC organizada por el NCSL Los patrones viajeros fueron 4 referencias Zener en esta comparaci n se hicieron correcciones por altitud y por deriva 3 En 1999 se particip nuevamente en la ILC NCSL en la cual se utilizaron 4 referencias Zener como patrones viajeros se hicieron correcciones por presi n atmosf rica y por deriva Se presentan los resultados respecto al N
64. ave used it as a traveling standard in international comparisons with the National Metrology Institutes of USA the Netherlands Germany 9 and Mexico and Japan 3 CONCLUSION The Calorimetric Thermal Converter developed at the National Research Council Canada is a unique versatile wide bandwidth converter that can be used in a voltage and a current mode At NRC all AC DC transfer frequency range extensions above 5 kHz are based on the characteristic of this converter NRC has participated in CCEM K6c Key Comparison of RF DC Transfer Standards as well as in a CCEM K12 Key Comparison of AC DC Current Transfer Standards Results of these comparisons conducted internationally at the highest levels of uncertainty fully validate the NRC CTVC design and calculations REFERENCES 1 J R Kinard T X Cai Determination of AC DC Difference in the 0 1 100 MHz Frequency Range IEEE Trans Instrum Meas vol 38 pp 360 367 1989 2 CJ van Mullem W J Janssen J P de Vreede Evaluation of the Calculable High Frequency AC DC Standard IEEE Trans Instrum Meas vol 46 pp 361 364 1997 3 E Scarioni M Klonz D Janik M Kampik High Frequency Thin Film Multijunction Thermal Converter on a Quartz Crystal Chip IEEE Trans Instrum Meas vol 52 pp 345 349 2003 4 R F Clark P S Filipski D C Paulusse Improvements in the NRC AC DC Transfer Capabilities IEEE Trans Instrum Meas
65. da P S Filtpski Application of a calorimetric thermal converter as a standard of ac dc voltage and current transfer difference Session FB1 14h40min National Institute of Standards and Technology NIST USA Rand Elmquist et al Transport behavior and characterization of precision 1 Q resistors for international comparisons Session FB1 15h00min Centro Nacional de Metrologia de Panama CENAMEP AIP Panama J Gonzalez et al Patr n de potencia el ctrica de alta exactitud basado en el muestreo digital de se ales de tensi n e intensidad alterna Session FB1 15h40min 11 3 SIM Electricity and Magnetism Metrology Working Group Meeting On June 14 from 14h to 18h the participants gathered together in the annual meeting of the SIM Electricity and Magnetism Metrology Working Group Meeting The agenda discussed points as follows 1 Introduction Welcome Introduction of the participants SIM representatives 2 Presentation Discussion of RADIAN RD 23 as a possible traveling standard for the proposed comparison on electric power 30 min presentation plus 10 min for questions RADIAN representatives 3 Agenda Approval of the Agenda Matters arising from the last CCEM meeting CCEM documents related to comparisons and CMC New SIM EM MWG webpage SIM representatives Chairperson 4 SIM EM S2 Electric Energy Comparison Final comments Pilot NIST 5 SIM EM K4 SIM EM S4 SIM EM S3 Capacitance Comparisons Add
66. de iff Te a anti T 0 Wi h ah a il E T HE aA aj izl i i 4 i al i ET HEE BTh 13 a Wi t rd tt mL wi H H H ml a i a l H a 2 amp amp ae Skk WIE N PR A O kee Tabla 4 Comparaci n a f p 0 5 capacitivo 00 He 0 5 bard jenp geile posar factor In giria in 41 Circa iy MIST IE SEMACYT CONACYT HIST W ART 753 HE zE Aig BERACYT IW m j 07h COWACYT may 44 aig a CERAM E Es LA TIE ARE 5 113 te 77 INMETHO 7 1 113 Fa IHM Ho on 180 Em INTI 13 H 41 aT Standard uncertain NST WE SEMACYT GOMACYT HIST Oo dij ii PHT KE 148 1 es SCT 112 1E mE GOMA TT ZAD Fihi ED 4 CENA dub 110 sTAD he i 1B 114 INMETAD Mm jdt 117 25 HHM HA 181 ihi 275 TI 41 183 if Phi CERAM if H 151 TH pa IB if HRC IKMETAG UTE IMTH 7 tt 103 inky 13 Ta Pa rh 11 ii 11 i Do 47 135 i HAC HEETEG LUE WTH 10 si 148 143 114 117 dra zh ii a ib E a 119 131 d d ie MET PETRO U ai bii ore al El pr Ei H in i a I suHisaes ine O INTi 1 Wij Ab 105 14 137 41 iz 121 4T 126 Mayor informaci n sobre SIM INTERNATIONAL COMPARISON OF 50 60 Hz ENERGY 2002 2007 puede encontrar en el Bolet n Informativo del Sistema Interamericano de Metrolog a OEA de diciembre de 2008 ViltSemetrO LA METROLOGIA ELECTRICA EN EL INTN Ing Robert Duarte Rodriguez Instituto Nacional de Tecnologia Normalizaci n y Metrolog a
67. de referencia lo cual demuestra su competencia t cnica para brindar servicios confiables En la comparaci n del 2008 en carga baja 0 5 A se logr obtener un ndice de compatibilidad menor o igual a 1 esto demuestra que las empresas contrastadoras est n mejorando su competencia t cnica en esta comparaci n las desviaciones con relaci n al valor de referencia del SNM no superan en general el 0 08 y sus incertidumbres son menores a la desviaci n Con el fin de evaluar y reforzar la competencia t cnica de las empresas contrastadoras se han programado dos comparaciones para el 2009 una de medidores monof sicos est ticos de tres hilos y otra de medidores trif sicos est ticos de tres hilos Las comparaciones se iniciar n en junio Hemos participado en la comparaci n SIM EM S2 SIM 1 4 Electric Energy cuyos resultados se muestran en el anexo 2 Nuestras diferencias de resultados con relaci n al laboratorio de referencia NIST en cuanto a las comparaciones con factor de potencia 1 0 y 05 inductivo son satisfactorias de igual manera en el caso del valor de las incertidumbres si sumamos el valor de la diferencia con la incertidumbre tendr amos un valor total en partes por mill n muy bueno lo cual da una referencia del nivel de nuestra competencia t cnica Para mayores detalles de nuestra participaci n ver anexo 2 Cabe se alar que no brindamos servicios de calibraci n para factor de potencia 0 5 capacitivo deb
68. dence The objectives of SIM are a cooperate in the development of National Metrology Institutes in each country in the region b contribute to the development of measurement infrastructure required to promote equity in trade c foster competitiveness and quality of the manufacturing sector in order to promote trade and commerce d identify sectors and institutions that can conduct specific multinational activities in support of metrology e contribute to the development of metrological infrastructure required to protect the environment and to promote the general well being of the population including its health and safety For this purpose measures taken by the members will help to achieve the following a the establishment of national and regional measurement systems b the establishment of a hierarchy of the national standards of each country and their linkage with regional and international standards c the compatibility of results obtained from measurement processes performed in laboratories within the system d the development of competitive technical and scientific personnel e the collection and distribution of technical and scientific information and documentation f the linkage with the several international organizations specialized in the area of metrology SIM has specific working groups each dealing with specific measurement quantities For more details consult http www sim metrologia org br SIM Electricity a
69. dor Para probar el sistema se utilizo la configuracion de la Figura 5 donde se introduce una senal patron de 32770 Hz para simular un cron metro con muy alta estabilidad en corto plazo Celda met lica E ae 0 Placas met licas Hacia el pre amplificador Cable coaxial Figura 5 Esquema de conexi n para la simulaci n El resultado de la simulaci n se muestra em la Figura 6 donde el ruido de las mediciones es mucho menor que el que producir a un cron metro comercial Este ruido es una de las componentes de incertidumbre del 32768 1864 W dl i e nuevo sistema de medici n li N nt NA e y A carentes CIA A ih g il id MNT IN Wi IN ij i i i T r La Tabla 2 muestra una comparaci n de factores de JU AL Bi ait i oe incertidumbre de comparaciones Para el m todo 32709562 manual se considera una resoluci n del objeto de 0 01 s 3 d as de per odo de calibraci n y reacci n manual de 0 025 s del metr logo Para el m todo inductivo se 32768 1368 32768 1366 Mutita hbi d ference D Ww 32770 008 32770 006 32768 136 32770 004 32770 002 32768 1356 100 200 300 400 500 600 700 800 900 1000 E 32770 S Figura 7 Medici n de un cron metro real
70. ductores de alta temperatura 1 SISTEMA PROPUESTO El sistema est basado en superconductores llamados de alta temperatura en este caso particular utilizamos el cristal denominado YBCO Ytrio Bario xido de Cobre Estos cristales tienen la propiedad de comportarse como conductores perfectos a temperatura del nitr geno l quido Con estos superconductores se construyo un chip de junturas Josephson el cual fue desarrollado por un conjunto de cient ficos de Alemania y Rusia 1 El chip consta de varias salidas cada 10 mV conectadas en serie pudi ndose obtener valores m ltiplos El conjunto es sumergido en un tanque de nitr geno l quido pero aislado del mismo por un tubo que contiene en su interior un ambiente con gas helio para que los elementos del chip se encuentren en un ambiente no corrosivo El tanque de nitr geno l quido se conecta una bomba para generar cierto vac o necesario para mantener la temperatura en el chip en el entorno de los 75 K Este sistema es controlado de forma autom tica a trav s de un dispositivo electr nico que comanda la bomba manteniendo la temperatura estable en 0 2 K En la Fig 1 se observa un diagrama del sistema Reloj Patr n 10 MHz Computador Tarjeta Frecuencimetro Voltimetro Adquisidora Contactos de baja FEM Sintetizador 70 75 GHz Osciloscopio Divisor Resistivo Fuente de Alimentaci n Fuente de Polarizaci n Regulaciones Temperatura
71. e given by Swerlein s algorithm Table 1 AC DC differences in up V V measures by Swerlein s algorithm and thermal converters at different frequencies this new expression 1s used to evaluated by means of least square adjustment a new set of parameters U U and U ances RREA ee i oe 5 03 2 03 1 53 1 67 in addition to the frequency correction df In this case the converters algorithm minimizes the sum of squares residuals R D elid Su 6 The whole process is done again until df is equal to zero The same process is done for the current samples estimating the parameters 1 and Z The validation of the measurement of phase was done using the procedure described in 9 by Stenbakken VIII Semetro Jo o Pessoa PB Brazil June 17 19 2009 Normal 1 Dual channel sampling Phase Source Reverse system 2 Fig 2 Connection diagram for the phase measurement calculations When measuring power any different between the time delay of the two channels changes the measurement of power factor Lets r be the time delay of the voltage channel and 7 T4 the time delay of the current channel Thus U U sin w kT 7 a 8 La 1sin w XT r 7 0 8 9 and the power is n 1 W Reos A we 2 cos 204 140042 2044 10 k 0 If the truncation error part of 10 is not significant then the error due the differential time delay Ey can be determined expanding the cosine term Mo
72. e han pasado a segunda muestra a disminuido notablemente 6 PROYECTOS EN DESARROLLO 6 1 Establecimiento de las etapas de verificaci n peri dica y verificaci n eventual Para el presente a o se tiene proyectada la ampliaci n de los controles hechos a los medidores de energ a el ctrica a fin de llegar a las etapas de verificaci n peri dica y verificaci n eventual despu s de reparaci n En vistas a dicho objetivo desde principios del presente a o se viene trabajando en el Comit Interinstitucional ANDE INTN en la elaboraci n del T rmino de referencia espec fico para la verificaci n eventual en base a los proyectos de la ANDE que establecen el reintegro al servicio activo de una cantidad significativa de medidores de energ a el ctrica en su mayor a monof sicos electromec nicos por lo que existe una necesidad impostergable de cumplimiento de esta etapa de control metrol gico VIII Semetro Joao Pessoa PB Brazil June 17 19 2009 Se prev arrancar con esta nueva actividad en el segundo semestre del a o 2009 utilizando como laboratorio de ensayos el establecido en la propia ANDE con un auditoria metrol gica previa a fin de comprobar fehacientemente el estado de calibraci n de los equipos y patrones que intervendr n en los diversos ensayos Para la etapa de verificaci n peri dica se busca incluir e interesar a los universidades y facultades que tienen carreras t cnicas afines de manera a q
73. e of other related meters used for billing purposes The topics will include Metrology bases of power and energy Traceability to primary standards Voltage dividers measuring transformers Principles of power measurements analogue instruments adding devices thermal converters TDM digital transducers Phase and power factor measurements Energy measurements in high voltages networks Effects of signal distortion I 2 VII International Seminar on Electrical Metrology VIII SEMETRO On June 17 18 and 19 the participants attended the VIII International Seminar on Electrical Metrology VII SEMETRO More information about the event can be found at http www inmetro gov br english news events V IIsemetro index as In the following table it 1s provided the schedule of the Seminar VI SEMETRO Schedule VII SEMETRO pete Testes pear O pear ses Tabe Room 07h oo 08h 20min OFh 10min 10h Opening DOmin Ceremony 10h 20min 50min i 11h 40min Welcome coffee Plenary 3 Plenary 4 Plenary 2 i a 30min Cabedelo Cabedelo Theater Room Room Plenary 5 Plenary 6 Coffee Break Session FAI Session FA 14h E i ee ae p Omin session WE Session WB2 Session IB Session IB Session FBI Session FB l h DOmin l h 30min Poster Session W Round Table Coffee Break 18h Reserved to Committee 00min Meetings 19h 00min 20h Opening Cocktail Closing
74. e used in the subsequent measurements The two DVMs are then connected as described in Fig 3 to measure the amplitude ratio lV IV and the phase displacement arg V arg V of the two output voltage signals The measured values are then inserted in 9 to obtain the reference values of capacitance ratio and dissipation factor for an unknown capacitor The calibration system can simulate any capacitance ratio from 1 1 to 10 1 other capacitance ratios can be simulated by using resistors of different values and any dissipation factor from 0 to 1 or more at power frequencies For standardization purposes the control software allows the user to simulate a integer capacitance ratios from 1 1 to 10 1 at a dissipation factor of 1 10 or b decadic dissipation factors from 1 10 to 1 at 1 1 capacitance ratio The corresponding amplitude ratio and phase displacement of the two voltage signals are then set and measured automatically The fine adjustment of the signal generators however may require user intervention The reference values of capacitance ratio and dissipation factor are then reported Several repetitions are made to evaluate the experimental standard deviation of the reference values due to the stability of the generators The average of the reference values over all those repetitions 1s finally reported The whole measuring process takes about two minutes for each test point The electronic bridge 1s set to the specific test po
75. ed using a usually linear model of the drift in the resistance values To determine the rate of drift and to assess the transport behavior of the standards several sets of measurements of low relative uncertainty made at the lead or pilot laboratory are needed Typically the standards travel to two or three participants and then return to the pilot laboratory for a set of closure measurements The linear model used in the analysis of the results does not account for changes in the values of the resistance standards that can occur due to mechanical and thermal shocks These changes may introduce systematic errors in the data and increase the uncertainty of the comparison They are sometimes a major component of the comparison uncertainty especially for laboratories that maintain a quantum Hall effect resistance standard Precision 2 resistors are normally maintained and measured at constant temperature and so are protected from thermal cycling except when they are transported or when they are intentionally measured at different temperatures to determine the characteristic behavior of the resistance value This behavior due to external temperature is described by a second order curve R T R lL a T T BT T Here R T is the resistance at temperature T and R is the resistance at a reference temperature T while a is the slope of the curve at 7 and B is the second order coefficient of resistance over some temperature
76. een calibrated at l sl 0 2 mA and l sl 0 02 mA with the system described above using R Rp 5 KQ and R R 50 KQ More recently such bridges have also been calibrated with R 50 KQ and R 5 KQ for capacitance ratios from 10 1 to 100 1 The standard uncertainties associated with the simulated reference values of capacitance ratio and dissipation factor at Zl 0 2 mA are listed in Table III and Table IV respectively In addition the standard uncertainties at l sl 0 02 mA are listed in Table V and Table VI The standard uncertainties for capacitance ratios from 10 1 to 100 1 are listed in Table VII They were evaluated from 9 by applying the GUM rules 18 The figures include the contribution associated with the stability of the generators Vcc YEE Fig 6 Amplifier circuit A TABLE HI CAPACITANCE RATIO Nominal ACACIA Cap Ratio k 1 1 1 0 000009 Zel 0 000014 3 1 0 000036 4 1 0 000033 5 1 0 000050 6 1 0 00011 7 1 0 00012 8 1 0 00012 9 1 0 00020 10 1 0 00021 1 Dy 1 10 and lsl 0 2 mA TABLEIV DISSIPATION FACTOR Nominal U Dx ef Dissip Factor k 1 1 10 0 000006 1 107 0 000006 1 10 0 000006 1 107 0 000008 1 10 0 000006 1 107 0 000012 9 Cx Cs 1 1 and Us 0 2 mA VIII Semetro Jo o Pessoa PB Brazil June 17 19 2009 TABLE V CAPACITANCE RATIO Nominal CAC Cap Ratio k 1 1 1 0 000017 2 1 0 000029 3 1 0 000058 4 1 0 000055 5 1 0 00012 6 1 0 0001
77. erva por lo tanto la existencia de una corriente continua como resultado de una tensi n continua si la juntura es enfriada hasta temperaturas en que los materiales utilizados se tornan superconductores r 0 Josephson predijo que adicionalmente aparecer una corriente alterna cuya frecuencia f es directamente proporcional a la tensi n U aplicada seg n la ecuaci n f A 3 En s misma la juntura trabaja como un convertidor entre frecuencia y tension vinculando ambas magnitudes mediante constantes universales Esta relaci n no depende de los detalles constructivos del dispositivo que la implementa ni de elementos que envejezcan y cambien lo que lo hace ideal para uso como patr n primario de tensi n Conociendo el valor de la constante de proporcionalidad el dispositivo no requiere ser contrastado contra otros patrones de tensi n para determinar su propio valor Solo se necesita conocer la frecuencia de la onda generada lo cual se implementa a partir de relojes at micos Para nuestro caso particular en la implementaci n de este patr n los resultados que obtuvimos en los escalones qu nticos se muestran en la Fig 2 la que muestra la forma caracter stica de los escalones quanticos con una amplitud de corriente 150 uA para el mismo nivel de tensi n de salida 60 mV en este ejemplo 3 COMPARACI N PATRONES CONTRA FUENTES Para escalar a tensiones mayores se usa un divisor resistivo 10 1 compuesto por 10 resisto
78. es de potencia 1 0 0 5 inductivo y 0 5 capacitivo El patron viajero fue un Radian modelo RM 11 La lista de participantes se muestra en la tabla 1 Tabla 1 Lista de participantes Fecha de medici n NIST USA Agosto 2002 Mayo 2007 ICE Costa Rica Julio 2003 SENACYT Panam Agosto 2003 Salvador Los resultados de la comparaci n a 60 Hz se muestran en las tablas 2 3 y 4 Tabla 2 Comparaci n a f p 1 oy paw lar Jr ra ET Mara Mir dl Ear MIT p p hi ET E Ai ELETI H E ii eo W EIA a so W MEE H n Ei EEN u F Ji ad Do H i m a F i Eme ran heb MOT EN MATI uyi a mj E rt HE f HE Mal A E ij i CANT EN ii ku Cid H iii x w E li E TEE IM ie E 1k m nT i Hr n Dihan DIA PR MAA UNO EA AM Lal th oN E o Eh di l qi E mr E E H 4 gt EH mM u HI 25 ie G E l y 4 ET H l i E fl Ei i i IOo m bi F Hi o o y E ii i EHS OHN GEC ENTRO U ATH Ga ET EE 7 F 1 y i nin ur Tir 7 T E i i En MOI Ma HEE i H H a y EX Ho l IE F H HE a da i Y H Ei a Tp y i di IE n a la we i Tabla 3 Comparacion a f p 0 5 inductivo MA Fe fic ies cpr in 48 re a ER MAET CT un 1 E mi er 2 i v E J aT Hj I wi m Aa i O J W Tian 1 ik Je I HE E i rhi WO H wiin H a kk nu p iW 7 g w mo 4 mp iF die a H AAA MOT EN aT Deer pu Mur i mi 14 mo fa nf ME E i E4 WT A E A in COMETA 1HE imi I C irate m uf IH iki i e W dk ju Pht y at w Mm WO EH if
79. estimation for the parameters Then expression 2 is expanded in series as a function of the frequency and truncated to the linear terms u n f U D a V2 cos 2h fr U V2 sin 2hafr 5 Sorma V2 sin 2hr fr U V2 cos 2hz fr sw To calculate power each parameter is corrected by the correction factor due to the finite time integration of the sampling DAC 6 m 7 sin Aff which depends on the frequency and the harmonic component After that the power is computed in three steps a Using the parameters calculated by least squares the value of power is calculated per burst and per harmonic b Then an average per burst is done As result we obtained the value of power per harmonic c The sum over all the harmonics is done 2 2 SOFTWARE VALIDATION The software validation is an important task because it links the sampling system to national standards In the case of Swerlein s algorithm we use thermal converters TC to validate the rms value calculated by the algorithm Fig 2 shows a scheme of the system used where HP3245 is a two channel source RM l is a computer controlled switch HP3458 is the DMM taking the samples K182 is a nanovoltmeter and Tcn is a thermalconverter Fig 2 Connection diagram to validate Swerlein s algorithm Using this procedure the same voltage is applied to the TC and the DMM Knowing the ac dc difference of the TC it is possible to calculate the error in the RMS valu
80. etrology Division of TTBS came officially into being The Division is composed of the Legal Metrology Inspectorate the Calibration Laboratory and the Standards Laboratory Since its creation the Metrology Division has sought to establish an internationally recognized and acceptable measurement system for all the measurements conducted in Trinidad and Tobago Prior to this however in the absence of the necessary legislative framework metrology in the TTBS developed VIII Semetro Jo o Pessoa PB Brazil June 17 19 2009 along the lines of a calibration service facility TTBS has been conducting electrical instrument calibrations since the late 1980 s We have over the years acquired and maintained many industrial clients who have come to routinely rely on our calibration services TTBS routinely calibrates Process Meters DMM s Insulation Testers and a number of other electrical measurement instruments Traceability was assured via the external calibration of measurement instruments by accredited laboratories After 2006 with the Standards Laboratory established as entity within the new division more emphasis is now being placed on securing new primary standards where deemed necessary and on ensuring internationally recognized traceability as far as possible though the Standards Laboratory 2 THE PRESENT CONTEXT The importance of a proper Metrology Infrastructure to efficient and sustained national development is wit
81. experiment and estimate accurately the signal parameters In addition buffer amplifiers to unload the digitizer inputs are not needed as the digitizers are used to sample directly the output voltages of the signal generators However techniques to offset the dependence of the injected currents on the impedance of the leads and the current comparator ratio windings are required The paper is organized as follows The calibration of high voltage standard capacitors with capacitance and dissipation factor standards and bridges is briefly reviewed in section 2 The construction of dissipation factor standards 1s discussed in section 3 The operating principle of the calibration system proposed here is presented in section 4 The measurement procedure is detailed in section 5 The characteristics and the construction of the error current injection amplifiers are discussed in section 6 The measurement uncertainties are reported in section 7 Experimental results are discussed in section 8 The conclusions are drawn in section 9 A two page summary of this paper was published in 7 An extended version of that paper was accepted for publication in 8 The paper here addresses further developments performed after the submittal of the paper in 8 2 THEORY A high voltage source a standard capacitor with known capacitance Cs and dissipation factor tan s and a capacitance and dissipation factor bridge are required to measure the unknown
82. f k 2 bridge 2 10 00130 0 00021 10 00135 20 00303 0 00032 20 00314 29 99826 0 00055 29 99858 40 0026 0 0015 40 00319 49 99751 0 00090 49 99814 60 0201 0 0026 60 02179 69 9993 0 0013 70 00066 79 9896 0 0027 79 99240 89 9988 0 0054 90 00114 100 0554 0 0042 100 0581 Dy 1 10 and l sl 0 2 mA 9 CONCLUSION A new approach for calibrating automated high voltage current comparator based capacitance and dissipation factor bridges has been presented Input currents from tens of UA to a few mA at power frequencies are synthesized as required for the calibration of such bridges The ratio and phase displacement of the input currents are estimated from the digitized data using an optimized algorithm for nonsynchronous sampling The estimates are used to calculate the reference values of capacitance ratio and dissipation factor The calibration system uses commercially available equipment It is possible to simulate capacitance ratios from 1 1 to 100 1 with relative standard uncertainties of less than 2 5 10 and dissipation factors from 0 to 0 1 with standard uncertainties of less than 1 10 The method has been applied to the calibration of commercial electronic bridges It is a refinement of an approach described earlier It leads to larger uncertainties but is slightly easier to implement since the digitizers need not be synchronized to the signal generators AKNOWLEDGMENTS Prof Endre Toth in memoriam constructed at In
83. frecuencia con el tiempo es el cambio de la relaci n entre el gas de rubidio y un gas buffer necesario para su funcionamiento Dicho gas tiene el cometido de bajar el movimiento de los tomos de los gases dentro de la ampolla de vidrio y es una de las causas del bajo ruido en medidas de corto plazo Pero tiene el inconveniente que los gases son muy lentamente liberados a trav s de las paredes del recipiente que los contiene cambiando la relaci n entre el gas de rubidio y el gas buffer y en consecuencia var a la frecuencia del oscilador Los mayores factores externos que influyen son las perturbaciones electromagn ticas Aunque estos dispositivos est n protegidos con blindajes existen campos propios que tambi n var an y no son totalmente inmunes a influencias externas 1 Por otro lado un punto a favor de estos relojes es que en medidas de corto tiempo tienen muy bajo ruido del orden de 3x10 12 en tiempos de 100 s ver Fig 1 Existe otro tipo de reloj llamado GPSDO GPS con oscilador disciplinado en el cual una conexi n GPS controla la frecuencia del oscilador generalmente de rubidio 2 El sistema GPS adem s de brindar el servicio de posicionamiento global puede tener salidas de frecuencia est ndar de 1 Hz 5 MHz y 10 MHz Algunos modelos pueden tener otras salidas usadas en telecomunicaciones de 1 544 MHz o 2 048 MHz Estos equipos a largo plazo no tienen deriva pues el sistema GPS es supervisado desde estaciones
84. goritmo de evaluaci n y correcci n de la deriva 3 CONCLUSIONES Este trabajo muestra un m todo por el cual es posible realizar correcciones en la frecuencia de salida de un reloj at mico de rubidio para mantenerla dentro de un entorno del orden de 1x10 Hz Hz De esta forma se obtiene una salida con un comportamiento de bajo ruido caracter stico de relojes at micos primarios sin las altas derivas que caracterizan a los relojes de rubidio El costo del sistema as formado es unas diez veces menor que el costo de relojes primarios de cesio 4 REFERENCIAS 1 Principio de funcionamiento relojes at micos de rubidio SIM Seminario Metrolog a Buenos Aires febrero 2008 2 Manual equipo Spectratime modelo GPSource 3 Manual equipo Spectratime modelo RMO BIOGRAF AS Leonardo Trigo M 98 nacio en Montevideo Uruguay en 1969 Se graduo en Ingeniero Tecnologico en Electronica expedido por Instituto Tecnologico Superior en 1993 Desde 1994 se desempe a funciones en el Departamento de Electrotecnia Subgerencia Laboratorio UTE Daniel Slomovitz M 86 SM 89 naci en Montevideo Uruguay en 1952 Recibi el t tulo de Ingeniero El ctrico en 1977 y Doctor en Ingenier a en 2000 en la Universidad de la Rep blica Uruguay Act a como Profesor Catedr tico en la misma A universidad En 1977 se incorpor al abonado de UTE como Ayudante de Ing ocupando actualmente el cargo de Jefe del Laborator
85. hat will perform in a superior manner in transport for comparison measurements at different laboratories Fig 5 shows a graph of the temperatures experienced by the SIM EM K1 transport standards between the first and second sets of measurements at NIST The range of temperatures is typical of that experienced in international air freight transport and the extremes in temperature are similar in magnitude to those in the tests shown in Fig 1 The transport standards showed reasonably good behavior even under these adverse conditions Based on the pilot laboratory data the values of the SIM EM Kl transport standards were relatively predictable and the residual differences from linear drift were of order 0 02 uQ throughout the comparison The extreme temperatures near 10 C at the beginning of the data in Fig 5 may also help to explain the drift in one Thomas type standard at the INTI laboratory in January 2006 35 30 4 gt pi 25 4 Temperature C o 15 10 1 Jan 06 15 Feb 06 Date 1 Apr 06 16 May 06 Fig 5 Temperature data measured in the transport container during part of the SIM EM K1 comparison This record covers only the first part of the comparison when the standards were shipped between the USA Argentina Brazil Uruguay and the USA Periods of temperature extremes were recorded in transport and while the package was held in customs The SIM EM K1 standards have relatively low pressure coeff
86. hout question Electrical Metrology in particular is of tremendous importance especially since so many other measurements in industry and otherwise depend on good electrical measurement accuracies in order to provide trusted data This trend too is likely to increase even more as technology becomes an ever larger and more important part of day to day activities especially since the country is aspiring to attain developed nation status by 2020 The Trinidad and Tobago economy is largely hydrocarbon based oil and gas to the extent that in excess of 40 of GDP is attributable to the direct and indirect sales of these natural resources 80 of exports These are unfortunately diminishing resources Industrial Production which is heavily energy dependent contributes in excess of 50 of GDP The industrial base includes the production of petrochemicals iron and steel food beverages prepackaged goods and agricultural products To ensure balanced and sustainable development and to curtail the economy s obvious over dependence on the fortunes of the oil and gas markets sustained growth in the non oil manufacturing and service oriented sectors has to be facilitated Further planned industries include aluminum production smelting and plastics Significant investments are also being made in Technical and Tertiary Education Along with a more educated and technically savvy populace advances in research and value added technolog
87. ia El ctrica de la Rep blica de Panam VIII Semetro Joao Pessoa PB Brasil Junio 17 19 2009 6 REFERENCIAS 1 G A Kyriazis Extension of Swerlein Algorithm for AC Voltage Measurement in the Frequency Domain IEEE Trans Instrum Meas Vol 52 NO 2 April 2003 2 R L Swerlein A lOppm accurate digital AC measurement algorithm in Proc NCSL Workshop 1991 pp Measurements 3 G A Kyriazis and R L Swerlein Evaluation of uncertainty in AC voltage measurement using a digital voltmeter and Swerlein s algorithm in CPEM Dig 2002 4 E T th and A Ribeiro Franco Power and Energy Reference System Applying Dual Channel Sampling JEEE Trans Instrum Meas Vol 54 NO 1 February 2005 5 E T th and A Ribeiro Franco Power and Energy Reference System Applying Dual Channel Sampling JEEE Trans Instrum Meas Vol 54 NO 1 February 2005 6 G Kyriazis An algorithm for accurately estimating the harmonic magnitudes of periodic arbitrary signals using asynchronous sampling CPEM Digest 2004 7 Agilent Technologies 3458A Multimeter User s Guide Edition 4 Copyright O 1988 1992 1994 2000 Agilent Technologies Inc All rights reserved
88. ical applications and products are anticipated as a result of these investments The advent of the Metrology Bill 2004 has made TTBS now more than ever before the critical element in the Measurement Infrastructure of the country and thus critical to the efficient effective and sustainable development of the national economy Some studies estimate that metrology contributes some 3 to 6 of GDP in industrialized economies and as much as 15 in developing economies 1 This along with the reality of the country s inordinate dependence on oil and gas and the imperative need to develop competitive industries both for domestic and foreign markets provides sufficient added motivation for the Metrology Division to actively pursue the establishment of an adequate effective and internationally recognized measurement system particularly in Low Frequency DC Metrology The Division s current strategy is to develop Low Frequency DC metrology to meet current and expected measurement needs and to participate in International measurement activities so as to ensure compatible measurements with international recognition and facilitate trade Thereafter with this measurement foundation firmly in place plans are to branch into the RF and AC Metrology areas as required in the national interest The planned developments in the Low Frequency DC Measurement areas are as follows 2 1 DC Voltage Metrology Our primary standards in DC Voltage consi
89. icients for Thomas type resistors This helped to reduce the uncertainty of the pressure corrections that were applied in the comparison The laboratory in Mexico CENAM Centro Nacional de Metrologia is situated at an elevation of about 1800 m above sea level Some Thomas type resistors would change in value by as much as 0 45 uQ 0 when measured at this altitude compared to their values at sea level or the altitudes at which most other SIM NMIs reside The changes in the two resistors used in the comparison were less than 0 12 uQ O and the uncertainty in the barometric pressure correction was less than 0 003 uQ O 5 CONCLUSIONS When selecting and characterizing standard resistors for international comparisons one must be aware of the effects transportation can have on precision resistors There are often pressure and temperature variations during international comparisons that are far greater than the day to day changes at any one laboratory site and careful selection of the transport resistors 1s necessary to minimize the effects of the laboratory measurement environment When a Thomas type 12 resistor experiences significant temperature changes in transport its value as measured at constant temperature may show hysteresis and may drift to a new stable value with a time constant of a few days This settling is sometimes followed by long term drift if the temperature variations were extreme The magnitudes of these effects depend
90. ido a que nuestros patrones no est n calibrados en dicho factor de potencia Estamos participando en la comparaci n SIM EM S1 SIM 1 5 voltaje and current resistance hemos realizado las mediciones correspondientes al patr n viajero DMM y lo hemos enviado al siguiente participante en abril de 2009 Tenemos como planes de desarrollo para los pr ximos a os la mejora en referencias de corriente continua y alterna adquiriendo un calibrador multifunci n Fluke 5720 juego de diez resistencias patr n una referencia zener DC En potencia estamos planificando desarrollar el servicio de calibraci n de transformadores de medida de corriente y de tensi n 3 CONCLUSIONES Como se puede apreciar el SNM ha desarrollado la Metrolog a en el Per y la sigue desarrollando en cumplimiento a sus funciones Contribuimos al crecimiento y fortalecimiento de la Metrolog a en el pa s a trav s de nuestra participaci n como expertos t cnicos en la acreditaci n de laboratorios de calibraci n apoyando la creaci n de una red de laboratorios acreditados as mismo Gerencia Operacionesdamos cursos de capacitaci n y entrenamiento El laboratorio de electricidad a trav s de su programa de comparaciones ayuda a fortalecer la competencia t cnica de los laboratorios de calibraci n y empresas contrastadoras ANEXO 1 Comparaciones nacionales con empresas contrastadoras Contrastaci n en campo Verificaci n 1 Comparaci n de med
91. idor de energ a el ctrica est tico monof sico de dos hilos clase 1 Para esta comparaci n se emple un medidor monof sico est tico de dos hilos clase 1 constante 1600 imp kWh 220 V 10 A 60 A para una frecuencia de 60 Hz Los ensayos se realizaron con una tensi n de l nea de 220V factor de potencia 1 frecuencia de 60 Hz y a las corrientes de 0 5 A 10 A y 60 A Los l mites de error para contraste en campo est n establecidos en la Norma DGE Contraste del Sistema de Medici n de Energ a El ctrica de la Direcci n General de Electricidad del Ministerio de Energ a y COMPARACION EN CARGA BAJA I 0 5 A F P 1 2007 SNM1 1 2 3 4 5 SNM2 PARTICIPANTES COMPARACION EN CARGA BAJA I 0 5 A F P 1 2006 0 5 0 4 03 u 0 2 0 1 SNM 3 5 7 9 SNM PARTICIPANTES Minas cuyos valores se muestran en la tabla siguiente Fig 1 Carga baja 2006 Fig 4 Carga baja 2007 Tabla 1 Limites de error Valor de Factor de Limite de error corriente potencia Clase 1 COMPARACION EN CARGA NOMINAL I COMPARACION EN CARGA 0 05 lb 10 A F P 1 2006 NOMINAL l 10 A F P 1 2007 0 7 0 80 0 6 0 70 _ 98 _ 060 04 0 40 w m W 030 Se realizaron dos comparaciones la primera 01 ofp comparaci n se realiz en el a o 2006 en la Cue ee ee ae LEERTE que participaron cuatro empresas PARTI
92. int and its readings are compared with the simulated reference values reported by the calibration system 6 CONSTRUCTION OF THE AMPLIFIERS Battery operated amplifier circuits are needed to offset the dependence of the injected currents on the impedance of the leads and the current comparator ratio windings They inject the error currents Such amplifiers have been used extensively in current comparator based bridges 16 17 The basic circuit of the amplifier A is shown in Fig 4 the circuit of the amplifier A is similar Assuming a voltage drop across the current comparator ratio winding N and interconnecting leads the voltage drop across the impedance Z in Fig 3 is V amp and the error current is then Z The amplifier outputs a voltage 2 so that the current Z is injected This current is nearly equivalent to the error current since Z and Z are equal in magnitude to R For instance assuming that y V Ri 5 KQ and that the current comparator ratio winding N has a resistance VII Semetro Jo o Pessoa PB Brazil June 17 19 2009 of about 1 Q and negligible leakage inductance the error current is 0 04 uA or two parts in 10 of the test current 0 2 mA Therefore precision resistors with 0 1 tolerance are required in the amplifier to provide the error current within a few parts in 10 The precision requirement is less stringent for R 50 kQ where the error current is 0 4
93. io Ha llevado a cabo investigaci n en mediciones de baja frecuencia y alto voltaje habiendo publicando m s de 100 trabajos y el libro Mediciones El ctricas del IEEE ViitSemetrO Sampling wattmeter at INTI Lucas Di Lillo H ctor Laiz Eliana Yasuda Ricardo Garc a Instituto Nacional de Tecnolog a Industrial INTI Argentina Idili inti gob ar Retired Instituto Nacional de Tecnologia Industrial INTI Argentina garcia levi O arnet com ar Abstract We developed an automated sampling reference system to measure electrical power The system allows calibration of instruments within an uncertainty of 20 uW VA at power frequencies It can also measure harmonic power Calibration is fully traceable to national standards All the components of the system can be separately evaluated and by this means its total uncertainty estimated Keywords Dual channel sampling phase measurements power standards 1 INTRODUCTION Electrical Power Laboratory at INTI developed in 1996 a thermal power comparator Since that time the primary power standard of Argentina has been based on thermal converters working with the well known sum and difference method 1 It provides high accuracy typically 20 W W at power factor one 2 With this system good results were obtained in the corresponding CIPM key comparison 3 The main disadvantage of the thermal power comparator is the time needed for one measurement typically 180 s
94. io del Laboratorio de Tiempo y Frecuencia del CENAM ubicado en otro edificio La conexi n se hace mediante un cable coaxial de aproximadamente 100 m de largo que aten a considerablemente la se al Para amplificar la se al de 10 MHz proveniente del reloj at mico se dise un amplificador ver figura 4 ubicado a la entrada del contador de frecuencia Con una ganancia en tensi n de 4 se produce una tensi n en la carga de 2 V pico Debido a que la impedancia de entrada del contador de frecuencia es de 300 Q se dise un transformador para ser colocado a la entrada de frecuencia de referencia externa del contador el cual permiti acoplar las impedancias y tambi n tener un aislamiento el ctrico respecto al reloj at mico con lo que mejor el amarre y la estabilidad en frecuencia del contador Se midi la estabilidad en frecuencia de la se al de referencia de 10 MHz a la salida del transformador usando la desviaci n de Allan y se encontr que es menor a 1X10 para tiempos de muestreo de 10 s a 82 000 s 6 CAMBIO DE TECNICA PARA EL ENFRIAMIENTO DEL CHIP Para obtener el efecto superconductor es necesario enfriar el chip Josephson a 4 2 K introduci ndolo en un tanque que contiene helio l quido Esta inmersi n debe ser hecha lentamente para evitar cambios bruscos de temperatura que da en al chip el proceso de enfriamiento toma aproximadamente 1 2 hora Con el chip PREMA se presentaron muchos problemas de flujo atrapado
95. ions The resistor is built with 10 Vishay resistors of 100 We use 10 resistors instead of one to run each resistor at one quarter of its nominal power Temperature coefficient TCR of the resistor 1s 0 5 K Despite of this low TCR the resistor is immerse in an oil bath and the internal temperature of the bath is monitored by a PT100 thermal resistance The value of the 10 Q resistor is corrected by the temperature measured by the PT100 Fig 4 Photograph of the 10 2 resistor and PT100 resistor to monitor the oil bath temperature Current transformer can be replacing by ac dc current shunts In our case we used 1A and 5 A shunts This shunts were calibrated with a Fluke 5700 calibrator in 1 A and 2 A respectively and the output voltage was measure with a DMM Agilent 3458 3 MEASUREMENT RESULTS To know the performance of the new sampling wattmeter we compared it with the thermal power comparator at 120 V and 1 A at power factors or 1 0 5 inductive and 0 5 capacitive Fig 4 shows a diagram of the connections used for this purpose VIII Semetro Jo o Pessoa PB Brazil June 17 19 2009 Table 3 shows the results and the uncertainties of the measurements The components in the uncertainty budget of the sampling wattmeter are expanded uncertainty e Sampling algorithm 5 uV V e Standard deviation of the measurements 10 uW VA e Current shunt 20 uQ 0 e Voltage transformer 5 uV V The total uncertainty of the
96. ish TTBS securely and intimately with the process of power supplies for consumption Thereafter efforts will be made to expand into energy measurements generally inclusive of chemical energy production and eventually to expand more fully into power measurements 3 CONCLUSION Electrical Metrology has to keep pace with the developmental thrust of the national economy Where this is not currently the case timely and thoughtful intervention will be made in the appropriate way As circumstances change the focus may be altered to suite but the path of continuous development and improvement in electrical metrology will not be altered By seeking to advance its level of measurement capability in voltage resistance time frequency power energy and impedance the Trinidad and Tobago Bureau of Standards is crafting the establishment of a proper national electrical measurement infrastructure that will over time contribute tangibly and intangibly to the improvement of electrical measurements nationally and by extension the development of the national economy and the quality of life of the society VIII Semetro Joao Pessoa PB Brazil June 17 19 2009 ACKNOWLEDGMENTS I would like to acknowledge the staff of the Metrology Division of the Trinidad and Tobago Bureau of Standards for providing me with information and materials for this paper and the corresponding presentation REFERENCES 1 Quinn T J Metrology its role in today
97. issipation factor function of high voltage capacitance bridges One needs a known standard capacitor Cs with negligible dissipation factor tan 0s 0 and a dissipation factor standard with known capacitance Cx and known dissipation factor tan dx Capacitor High side Shielded Reference Capacitor Shielded Conductance Box Fig 2 Dissipation factor standard Such standards consist of a series connected parallel arrangements can also used but are not studied here three terminal standard gas capacitor and a three terminal conductance shown schematically in Fig 2 where C z is the direct capacitance of the shielded reference capacitor G3 is the conductance between the terminals of the shielded conductance box and C44 C34 and C4 are stray capacitances to ground Note that C24 comprises the sum of two parallel ground capacitances C4 and C gt 4 of the component boxes and coupling connector The design is similar to that described in 3 It is straightforward to show that the dissipation factor of the network is 3 tan x C Cr Gy 5 Also the effective parallel conductance G 3 of the network is capacitance C and C C 1 tan 62 6 Ga WC tan 6 1 tan 5 2 The equivalent capacitance C3 is the original three terminal capacitance C reduced by a factor of 1 tand The dissipation factor tan x as seen from 5 is directly influenced by the presence of the combined stray junc
98. ith i j th element cos 2Tfo t ktp for j 1 2 3 and sin 2tG 3 fo t ktp for J 4 5 6 W is the known N x 6 matrix with i j th element cos 2T ft ktp d for j 1 2 3 and sin 20 3 fo ti ktp d for j 4 5 6 and x is the 6 vector of fitting parameters for each DVM uncorrected for the systematic effects The vector x is estimated from the average of the discrete Fourier transforms over all acquisitions 14 15 9 n 1 X p nN wo ot Y pk 11 where the prime means transpose Denoting by x j the j th element of x the fundamental voltage amplitude ratio and phase displacement are Mal koci 2 1 x3 4 Vv Kye x 1 x 4 argV argV tan where kpci kpc 18 the ratio of the corrections for the de voltage mode error of each DVM The above equations require knowledge of the delay d and the ratio kpc kpc2 In order to evaluate them an initial voltage measurement is done with GEN1 output signal applied to both DVMs GEN2 output is now left disconnected In this case the reported voltage amplitude ratio and phase displacement should ideally be unity and null degree respectively The algorithm measures the uncorrected values assuming d 0 and kpcj kpc2 1 and evaluates the delay d and the ratio kpcj kpc2 so that the readings 1 000000 and 0 0000 are reported for the amplitude ratio and phase displacement respectively The corrections are very stable 6 12 and ar
99. itional information needed for Draft B Report and publication Pilot NiST 6 SIM EM SS Digital Multimeter Comparison Review of measurement progress and traveling standard distribution Measurement schedule Review of draft report Pilot NIST 7 SIM EM K6 a SIM EM K9 SIM EM K11 AC DC Transfer Comparison Final comments Pilot CENAM 8 SIM EM K1 SIM EM K2 SIM EM S6 DC Resistance Comparison Final comments Pilot NIST 9 SIM EM K3 Inductance Comparison Review of measurement progress and traveling standard distribution Measurement schedule Review of draft report Pilot Inmetro 10 New and Proposed Comparisons Proposed regional projects and pilot studies AC Power Comparison proposed by CENAM AC DC Current Transfer Comparison proposed by INTI JVS bilateral comparison between NIST and Inmetro SIM EM BIPM K10 b 1 SIM representatives 11 SIM and inter regional CMC review CMC SIM EM 03 2009 inter regional review status CMC COOMET EM 04 2009 pending review CMC EURAMET EM 06 2009 pending review SIM reviewers 12 Next SIM EMWG Meeting Proposal for the next meeting to be held at INTI Chairperson Rio de Janeiro July 27th 2011 ViitSemetrO Developing Electrical Metrology in Trinidad and Tobago Francis Hamilton Trinidad and Tobago Bureau of Standards Century Drive Trincity Industrial Estate Macoya Tunapuna Trinidad and Tobago 868 662 4481 868 663 4335 Fax Francis Hamilton ttbs org tt Abstract This paper provides an overview of
100. l gico de 16 bits que permite obtener pasos de aproximadamente 38 uV al cambiar el bit menos significativo Debido a que la idea es lograr un sistema autom tico se usa un microcontrolador encargado de variar las se ales digitales que se aplican al conversor seg n informaci n enviada v a comunicaci n RS232 En el diagrama de la Fig 3 se observa que el reloj de rubidio el circuito de control y el microcontrolador forman un nico equipo llamado Frequency Standard Rubidium Adem s dicho equipo posee divisores de frecuencia que permiten tener salidas de 10 MHz 5 MHz 1PPS y una salida de frecuencia variable en d cadas de 1 Hz a 10 MHz seleccionable por medio de una llave HP 53132A GPS source 10Mhz 1pps SYNTH AA A MICRO RE a 10 Mhz CONTROLADOR wy 4 AA y E SS Y AAA A Tr 1 y 5 E DIV FREQUENCY as py o o 0 a o Wir 5Mhz 10Mhz Selec FREQUENCY STANDARD RUBIDUIM Fig 3 Diagrama en bloques del sistema Fig 4 Foto del equipamiento que compone el sistema El GPSDO entrega una frecuencia est ndar de 10 MHz la cual se compara con la senal del rubidio durante varias horas tiempo necesario para obtener una proyecci n de la deriva y en funci n de sta modificar la tensi n de control aplicada al rubidio para lograr el valor de correcci n de su frecuencia Un contado
101. lez cenamep org pa Nacional de Metrologia de Panama INTN Instituto Robert Duarte robertduarte intn gov py Nacional de Tecnolog a Normalizaci n y Metrolog a INTN Instituto Ever Cabrera evercabrera yahoo es Nacional de Tecnolog a Normalizaci n y Metrolog a Peru SNM INDECOPI Henry Postigo hpostigo indecopi gob pe Servicio Nacional de Metrolog a Instituto Nacional de Defensa de la Competencia y de la Protecci n de la Propiedad Peru SNM INDECOPI Henry Diaz hdiaz wWindecop1 gob pe Servicio Nacional de Metrolog a Instituto El Salvador Paraguay Paraguay Nacional de Defensa de la Competencia y de la Protecci n de la Propiedad Trinidad TTBS Trinidad Tobago Francis Francis Hamilton ttbs org tt and Tobago Bureau of Standards Hamilton Besides an annual meeting of SIM EMWG held on June 14th tutorials and the VII were held according to the following Schedule Schedule SIM EM MWG Training and Development June 15 16 2009 dune 15 June 16 June 17 June 18 June 19 09 00 10 40 DC Voltage AC DC Transfer Part I Part I Carles Aviles Peter Filipski CENAM NEC 10 40 11 00 Coffee break 11 00 13 00 DC Voltage AC DC Transfer Part II Part II Carlos Aviles Peter Filypski CENAM NEC 14 00 15 40 DC Resistance Power and Energy Part I Part I Rand Elmquist Daniel Slomovitz NIST UTE 16 00 18 00 DC Resistance Power and Energy Part II Part II Rand Elmqust
102. lly and thermally due to the annealing and mounting process used in their construction It has been shown however that the temperature coefficient of the Evanohm wire used in the NML resistors can vary along the length of the winding 3 and in the presence of a temperature Certain commercial equipment instruments or materials are identified in this paper to specify the experimental procedure adequately Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose gradient this can produce a change in the measured value of the resistance The Thomas type resistors made from Manganin are much more sensitive to temperature and pressure than standards made from Evanohm and these effects are thought to increase the uncertainty of resistance measurements based on the Thomas standards The bifilar coil of Manganin wire is sealed within a double walled cylindrical brass container and is wound tightly on the silk insulated wall of the inner cylinder 3 CHARACTERIZATION Over the past five years NIST has used two automated direct current comparator DCC bridges to measure precision 1 Q lresistors Temperature and pressure characterization requires two auxiliary thermal oil baths Thus the temperature of resistors can be altered independently from th
103. m Meas vol 55 No 2 pp 496 499 April 2005 5 E Toth A M R Franco R M Debatin Power and energy reference system applying dual channel sampling IEEE IEEE Trans on Instrum Meas vol 55 No 1 pp 404 408 Feb 2005 6 R L Swerlein A 10ppm Accurate Digital ac Measurement Algorithm Hewlett Packard internal publication Aug 1991 7 U Pogliano Use of integrative Analog to digital converters for high precision measurement of electrical power IEEE Trans on Instrum Meas vol 50 N 5 october 2001 8 G A Kyriazis Extension of Swerlein s algorithm for AC voltage measurements in the frequency domain IEEE Trans on Instrum Meas vol 52 No 2 Apr 2001 9 G Stenbakken Dual channel sampling systems paper for Digital Methods in Waveform Metrology Seminar Nat Bur Stand U S Spec Publ 707 Proceedings of the Seminar on Digital Methods in Waveform Metrology B A Bell Ed pp 55 73 Oct 1985 VIII Semetro Joao Pessoa PB Brazil June 17 19 2009 APPLICATION OF A CALORIMETRIC THERMAL CONVERTER AS A STANDARD OF AC DC VOLTAGE AND CURRENT TRANSFER DIFFERENCE Piotr S Filipski National Research Council Ottawa Canada Peter Filipski nrc cnre gc ca Abstract At the National Research Council of Canada NRC the primary standard of AC DC transfer difference at frequencies from 10 kHz to 100 MHz is a Calorimetric Thermal Voltage Converter CTVC Because of a simple design
104. me scales across the world must be closely coordinated and must not fluctuate from microsecond to microsecond from minute to minute or from day to day In addition traceable radio frequency measurements need to be done to ensure the security and quality of the communication network This is what we call electrical metrology All these measurements need to be reliable and traceable to a National Metrology Institute NMI in each country This traceability is ensured by periodic calibration of the industry standards in the National Calibration Network of each country Also the calibration network standards are sent to the NMI to be calibrated periodically In order to provide confidence among the traceability chains of each country international comparisons on electrical quantities are held periodically among the several NMIs of the respective Regional Metrology Organization RMO Several RMOs have been setup in many parts of the world The Inter American Metrology System SIM is the RMO of the Americas Inter American Metrology System SIM The Inter American Metrology System SIM resulted from a broad agreement among national metrology organizations from all 34 member nations of the Organization of American States OAS Created to promote international particularly Inter American and regional cooperation in metrology SIM is committed to the implementation of a Global Measurement System within the Americas in which all users can have confi
105. ment of electric power by means of high accuracy digital sampling is presented The method applied it s based in the reduction of voltage to a range of 0 10V using an inductive divider and also a reduction of the current by means of a current transformer and an incorporated standard resistor to obtain a voltage relative to the current intensity With this two voltmeters are used in the 10V range which 1s accurately calibrated with the standard diode zener of 10V So far deviation less than SOppm has been achieved these results were obtained by comparison with the travel standard of Argentina The results are promising and it is expected to reach the deviations of less than 30ppm Palabras clave potencia el ctrica muestreo digital algoritmo de Swerlein multimetros digitales 1 INTRODUCCION El diseminar en el pa s o regi n una determinada unidad de medida constituye una de las principales funciones de todo centro o instituto nacional de metrolog a El CENAMEP en cumplimiento de esta funci n desarrolla el patr n de energ a el ctrica basado en el muestreo digital con el cual pretende verificar el patr n de potencia actual de 100ppm Lograr actualmente mediciones de potencia el ctrica y de otras magnitudes de corriente alterna con alto grado de exactitud es de suma importancia para todo el mercado el ctrico tanto distribuidor como el consumidor Sin embargo la mayor a de los equipos dise ados para hacer este tipo de
106. metro the dissipation factor standards discussed in section 3 that had been used in an old calibration system Renata Teixeira de Barros Vasconcellos helped me with the operation of the old system after he passed away Renata also participated in an early stage of this new development and helped me with the initial tests I thank her for that I thank also Flavio Senna Acon and Dimas Barbosa Teixeira for building the amplifiers They did a great job I am also very grateful to Alexandre Etchebehere for suggesting and implementing the solution illustrated in Fig 6 to the amplifier problem reported Ronaldo Miloski Pessurno was also very instrumental in providing resources for this work I thank also Flavia No mia Cerqueira Leite Geraldo for helping me with recent calibration tests for customers Finally I wish to thank Luiz Macoto Ogino for providing the resources for this work REFERENCES 1 P Osvath and S Widmer High voltage high precision self balancing capacitance and dissipation factor bridge for industrial measurements 4th Int Symp High Voltage Engineering Conf Dig Athens Greece Sep 5 9 1983 pp 64 01 03 2 E So A microprocessor controlled high voltage current comparator based capacitance bridge IEEE Trans Pow Deliv 5 no 2 pp 533 537 Apr 1990 3 R D Simmon G J FitzPatrick and O Petersons Calibration of dissipation factor standards IEEE Trans Instrum Meas 48 no 2 pp
107. n for Standardization VIII Semetro Jo o Pessoa PB Brazil June 17 19 2009 VIIHSemetrO CONTROL DE LA DERIVA EN OSCILADORES DE RUBIDIO Leonardo Trigo Daniel Slomovitz LABORATORIO de UTE Montevideo Uruguay Itrigo ieee org Resumen Los osciladores at micos de rubidio se caracterizan por tener bajo ruido en medidas de corto plazo mientras los sistemas GPSDO GPS con oscilador disciplinado generalmente dicho oscilador es de rubidio adem s de brindar el servicio de posicionamiento global pueden tener salidas de frecuencia est ndar Dichos equipos poseen alto ruido en medidas de corto plazo pero a largo plazo no tienen deriva pues el sistema GPS es supervisado desde estaciones terrestres desde las cuales se realizan correcciones a los sat lites que compone el sistema Este trabajo propone implementar un sistema autom tico con el cual compensar la deriva caracter sticas de osciladores de rubidio comparando dicha salida con la salida del GPSDO con lo cual se obtendr a la estabilidad a largo plazo del GPSDO y el bajo ruido a corto plazo t pico del rubidio Palabras clave Reloj at mico Rubidio GPS Cesio 1 INTRODUCCI N Los osciladores at micos de rubidio no se consideran patrones primarios pues su frecuencia varia con el tiempo debido a caracter sticas propias de su funcionamiento y adem s existen influencias externas que cambian el valor de la frecuencia La mayor causa del cambio del valor de la
108. nd Magnetism Metrology Working Group The SIM Electricity and Magnetism Working Group SIM EM MWG is concerned with a promoting closer collaboration among SIM laboratories in projects related to electrical metrology and measurement services b optimizing the use of EM resources and services of the SIM laboratories and foster the development of these EM services so they may satisfy regional demands c documenting the traceability of EM measurement systems in SIM laboratories and encourage the regional acceptance of this traceability in accordance with international definitions and trends d evaluating the current status of the ongoing international comparisons on electrical quantities among the SIM laboratories and studying the future EM comparison needs of SIM laboratories e supervising SIM EM comparisons taking the necessary measures to expedite them in case of delays f harmonizing procedures proposed by the SIM EM MWG to perform EM comparisons of SIM laboratories and g evaluating the training and development needs of SIM laboratories In order to accomplish the above goals annual meetings have been organized attached to training and development events The Project SIM Training and Development on Electrical Metrology The main objective of the SIM T amp D on Electrical Metrology was the training and capacity building of country representatives in the field of electrical metrology For that it has been envisaged the organization of
109. niel 2008 Calibraci n de cron metros digitales por m todo de inducci n Extra do el martes 04 de noviembre del 2008 de http iie fing edu uy publicaciones 2008 TS08 Servicio Nacional de Metrolog a Indecopi Per Henry Postigo Linares RESUMEN Se describe al Servicio Nacional de Metrolog a sus funciones laboratorios de calibraci n que tiene principales servicios de calibraci n que brinda el apoyo que realiza hacia el sector p blico y privado y en forma algo m s detallada las actividades del laboratorio de electricidad PALABRAS CLAVE Metrolog a calibraci n laboratorios servicios electricidad 1 INTRODUCCION El Servicio Nacional de Metrolog a SNM fue creado el 6 de Enero de 1983 mediante la Ley N 23560 y ha sido encomendado al Indecopi mediante el Decreto Supremo DS 024 93 ITINCI El Servicio Nacional de Metrolog a fue creado para promover el desarrollo de la metrolog a en el pa s y contribuir a la difusi n del Sistema Legal de Unidades de Medida del Per SLUMP El SLUMP tiene como base e incluye totalmente en su estructura al Sistema Internacional de Unidades SI 2 SERVICIO METROLOGIA El Servicio Nacional de Metrolog a cuenta con Laboratorios Metrol gicos debidamente acondicionados instrumentos de medici n de alta exactitud y personal calificado Cuenta con un Sistema de Gesti n de la Calidad que cumple con los requisitos de las Normas ISO 9001 e ISO IEC 17025 con
110. nsformers and for assessing the dielectric properties of power apparatus insulation with respect to safety quality and service life Such bridges have been calibrated with gas dielectric standard capacitors and dissipation factor standards 3 see section 3 for constructive details of dissipation factor standards Some shortcomings of this method are a a high voltage apparatus is required b the number of test points is restricted to the number and values of the standards available and c the dissipation factor uncertainty increases with the actual dissipation factor being measured thus limiting the accuracy of loss measurements reported by bridge manufacturers A more flexible and accurate calibration procedure has been proposed in 4 Neither high voltage capacitors and dissipation factor standards nor a high voltage source are required The calibration of the bridge is carried out at low voltage These bridges measure the ratio of their input currents For the calibration two sinusoidal currents are synthesized with the aid of a digital programmable two channel ac voltage source and two resistors The complex VIII Semetro Jo o Pessoa PB Brazil June 17 19 2009 ratio of these synthesized input currents is calculated from an ac voltage ratio determined by a sampling method together with the impedance ratio of the resistors The system uses a synchronous sampling technique which requires the timing of the digital sou
111. ntal frequency f can be known from the number of null crossings of the signal applied to DVM1 The sampling parameters are evaluated as in 13 see Table ID A total of n acquisitions of N samples at times t itsamp i 0 1 N 1 are taken The internal level trigger of DVM is used to start each k th acquisition k 0 n 1 delayed by ktp from a signal null crossing where fp approaches 1 nf The corresponding acquisitions of DVM2 are delayed by ktp d from those signal null crossings where d is the delay between the two time series due to the external trigger delay and the DVM phase responses The A D converter aperture times of both DVMs are selected to prevent trigger too fast errors faper fsamp 0 00003 s 13 TABLE I SAMPLING PARAMETERS Parameter 50 Hz 60 Hz n 2 12 N 1127 1144 laip 0 001118 s 0 001049 s pore 0 001088 s 0 001019 s fo 49 998997 Hz 59 998814 Hz 2T fod 155 10 urad 186 13 urad It is assumed that each acquisition can be fitted with a truncated Fourier series with three harmonics this is reasonable as low distortion signal sources are being used to generate the sinusoidal signals The model assumes that the data set has a zero mean value any nonzero average value has been subtracted from the data In matrix notation Y oc WoeX gt 10 where the subscript p 1 for DVM1 and p 2 for DVM2 Ypx 18 the N data vector at the k th acquisition for each DVM Wi is the known N x 6 matrix w
112. nto a los metr logos encargados del desarrollo del proyecto y E a J HET ie ity A Fig 2 Los autores y los equipos que componen el patr n de potencia el ctrica PPEAE Las pruebas iniciales realizadas con el patr n de potencia arrojaban una dispersi n en los resultados de las mediciones alrededor de 50ppm Una revisi n en las conexiones entre los equipos que conforman el sistema de medici n aunado a la mejora de la toma a tierra del laboratorio de electricidad lugar donde se practicaban los ensayos permiti la disminuci n del desv o medio est ndar de los resultados hasta unas 18 ppm En la Tabla 1 y 2 se aprecia la mejora en la desviaci n de los resultados luego de optimizar las conexiones y la toma a tierra del laboratorio Las mediciones presentadas corresponden a la calibraci n del patr n de trabajo de energ a y potencia el ctrica del CENAMEP de clase 0 02 Luego de mejorar las desviaciones que presentaba el patr n de potencia el ctrica en sus mediciones el siguiente paso corresponde en lograr la validaci n del programa en cuanto a este punto la validaci n se encuentra desarrollada en un 50 ya que en marzo del presente a o se realiz en Panam una primera comparaci n con el INTI empleando como referencia su patr n de potencia viajero C1 2 Actualmente se est a la espera de la emisi n de los resultados por parte del INTI con los cuales poder ultimar detalles del sis
113. ny Novgorod Rusia en 1969 Desde 1993 se desempena en el Research Center Julich Alemania Su tema de investigaci n actual se relaciona con junturas Josephson de alta temperatura T para aplicaciones en metrolog a quantica de voltaje Es autor de 54 publicaciones y posee seis patentes ViitSemetrO A New Approach for Calibrating High voltage Capacitance and Dissipation Factor Bridges Gregory A Kyriazis Instituto Nacional de Metrologia Normalizac o e Qualidade Industrial Duque de Caxias RJ Brazil Email gakyriazis inmetro gov br Abstract A new approach for calibrating automated high voltage current comparator based capacitance and dissipation factor bridges is presented The approach is slightly different from another published previously It leads to larger uncertainties but is slightly easier to implement since the digitizers need not be synchronized to the signal generators It is possible to simulate capacitance ratios from 1 1 to 100 1 with relative standard uncertainties of less than 2 5 107 and dissipation factors from 0 to 0 1 with standard uncertainties of less than 1 10 Keywords calibration sampling methods dissipation factor ac bridge capacitance 1 INTRODUCTION Commercial automated high voltage current comparator based capacitance and dissipation factor bridges 1 2 have been used extensively for calibrating high voltage standard capacitors shunt reactors and power tra
114. o Su alto costo tanto en el momento de la compra como en el momento de cambiar dicha ampolla ha motivado este estudio de mejoramiento de los relojes basados en rubidio La idea clave es implementar un sistema automatico el cual compense la deriva caracteristica de estos osciladores comparando dicha salida con la frecuencia promedio de un reloj GPSDO Si el promedio se computa a lo largo de varias horas se minimizan los efectos del ruido caracteristicos del GPSDO De esta forma se obtiene el bajo ruido caracteristico de relojes atomicos de primarios sin las altas derivas que caracterizan a los relojes de rubidio 2 DESCRIPCION DEL SISTEMA El sistema esta compuesto por un GPSDO un reloj at mico de rubidio un circuito electr nico de control un contador universal y un computador En la Fig 3 se observa un diagrama de dicha configuraci n y en la Fig 4 una foto de los instrumentos El reloj de rubidio 3 permite la variaci n de su frecuencia de salida 10 MHz en funci n de una tensi n de control Dicha tensi n puede variar de O a 5 V siendo el cambio de frecuencia aproximadamente 5x10 Hz V El objetivo es controlar la frecuencia en pasos de 1x 10 Hz Hz o menores El circuito de control est formado por un zener de referencia de 10 V asociado a un divisor resistivo de alta estabilidad compuesto por resistores Vishay de relaci n 4 1 que entrega un voltaje de 2 5 V Dicha tensi n es aplicada a un conversor digital ana
115. o the Type B uncertainty for state of the art resistance measurements Figure 2 illustrates the behavior of each type of standard due to power loading Only the Thomas type resistors follow the direct relationship between power loading and the temperature coefficient The random power loading effects observed in the NML standards are thought to be related to thermal gradients as described earlier For the data shown in Fig 2 the resistors were maintained in an oil bath with relatively slow laminar circulation Both types of precision 1 Q resistors can exhibit a measurable power loading with 100 mA applied current 10 mW applied power in this oil bath but the effect can be reduced by measuring the resistors at 50 mA 2 5 mW Many commercial bath designs utilize turbulent flow and tests at NIST have shown that such baths also reduce power loading effects in both types of resistor 0 04 Thomas 0 02 a NML 0 00 slope 0 0062 0 0029 C 1779882 2005 0 0053 0 0097 2 1820 0 5429 1779885 2005 0 0020 0 0067 2 0542 0 5467 1842307 2005 0 0032 0 0001 2 8132 0 5234 Change in Resistance 1102 22 e n 0 04 0 06 1844269 2005 0 0015 0 0160 2 4710 0 5298 100 000 4 00 200 300 400 500 6 00 1883403 2005 0 0088 0 0229 2 3968 0 4961 1883409 2005 0 0118 0 0647 3 1296 0 4967 1883418 2005 0 0136 0 0661 2 1374 0 4962 First Order Temperature Coefficient a O O C
116. oltage transformer VT is used It has 3 ranges for 240 V 120 V and 60 V with a secondary of 6 V We choose 6 V at the output to use the DMM in the 10 V range To measure the error of the transformer in module and phase a lock in was used to compare the VT with a two stage standard voltage transformer calibrated at PTB Fig 3 shows the connection diagram of the set up where PSV110 is a Lock in ITV 1 is the standard transformer and X is the transformer under test Fig 3 Connection diagram for calibration of the voltage transformer Measured error in the VT at nominal input voltages of 6 uV V and 8 urad are corrected by software Due to the errors of the VT we do not use a compensation transformer 2 4 CURRENT CHANNEL At the current input of the sampling wattmeter there is a multirange current transformer CT 10 0 1 0 1 A To measure the error of the current transformer in module and phase angle the same scheme as in the VT calibration was used The CT was calibrated with a current transformer calibrated at PTB Fig 4 shows the connection diagram of the calibration system ITV 1 is the standard transformer and X is the transformer under test Fig 3 Connection diagram for calibration of the current transformer Errors measured at nominal input currents of 2 uA A and 2 urad were measure are corrected by software A resistor of 10 Q is connected to the secondary of the CT thus we get a voltage of 1 V under nominal condit
117. on the individual characteristics of each resistor REFERENCES 1 Jones K Gabriel W P Second APMP Resistance Intercomparison EEE Trans Instrum Meas 1995 44 196 198 2 Elmquist R E Jarrett D J Zhang SIM EM K1 K2 S6 RMO Comparison Final Report Metrologia 2009 46 Tech Suppl 01001 3 Pritchard B J and Small G W Temperature Coefficient Variations in Evanohm and Their Effect on the Transient Behavior of the NML 1 2 Resistors IEEE Trans Instrum Meas 42 1993 4 Bridgman P W The Physics of High Pressure G Bell and Sons Ltd London 1949 5 Pritchard B J and Luong K S Pressure Coefficient of a sealed NML 10 resistor Proceedings of the Sixth Biennial Conference of the Metrology Society of Australia held at the Australian National University October 2005 6 Jones G R and Elmquist R E Temperature and Pressure Coefficients of Resistance for Thomas 1 2 Resistors NCSLI Measure 2 2 2007 ViitSemetrO Patron de Potencia El ctrica de Alta Exactitud Basado en el Muestreo Digital de Se ales de Tensi n e Intensidad Alterna 1 E 3 MENE Anselmo Araolaza Julio Gonz lez Carlos Espinosa Luis Mojica ICENAMPP Panam aaraolaza cenamep org pa CENAMEP Panam gonzalez Ocenamep org pa CENAMEP Panam cespinosa O cenamep org pa CENAMEPP Panam Imojica cenamep org pa Abstract A system for the measure
118. os resultados de las comparaciones se muestran en el anexo 1 Evaluaci n de documentos y de personal t cnico de laboratorios que desean acreditarse Nuestro personal act a como experto t cnico En cuanto a las comparaciones realizadas ver anexo 1 podemos indicar que esta pr ctica nos permite ver la competencia t cnica de las empresas contrastadoras y determinar las acciones correctivas y de mejora a implementar en aquellas cuyos resultados no son aceptables Podemos apreciar en las comparaciones del 2006 y 2007 medidor viajero est tico monof sico de dos hilos clase 1 que en el caso del participante con s mbolo Oo amarillo sus resultados muestran una tendencia a alejarse del valor de referencia valor del SNM esto a permitido recomendarle que verifique su sistema de calibraci n incluido el patr n en periodos cortos con el fin de determinar las causas de la deriva y realizar las correcciones correspondientes de no ser as corre el riesgo de desaprobar un medidor que est dentro del l mite de error y aprobar un medidor que est fuera del l mite de error en el caso del participante con s mbolo 3 azul podemos decir que mejor sus resultados del 2007 comparados con el 2006 esto es un indicador de que ha mejorado su competencia t cnica lo que le permite brindar servicios confiables en cuanto al participante con s mbolo rojo a mantenido sus errores e incertidumbres peque as muy cercanas al valor
119. os resultados de las comparaciones del 2006 y 2007 Los ensayos se realizaron con una tensi n de l nea de 220V factor de potencia 1 frecuencia de 60 Hz y a las corrientes de 0 5 A 10 A y 60 A Los l mites de error para contraste en campo est n establecidos en la Norma DGE Contraste del Sistema de Medicion de Energ a El ctrica de la Direcci n General de Electricidad del Ministerio de Energia y Minas cuyos valores se muestran en la tabla 1 Se realiz una comparaci n en el a o 2008 en la que hubo cuatro participantes identificados con las letras 1 T J y G tres participantes fueron empresas contrastadoras y un participante fue una empresa en v as de autorizaci n Los cuatro participantes fueron los mismos que participaron en la comparaci n del a o 2007 Los resultados se muestran en las figuras 7 8 y 9 COMPARACION EN CARGA BAJA 1 0 5A F P 1 2008 PARTICIPANTES Fig 1 Carga baja 2008 COMPARACION EN CARGA NOMINAL I 10 A F P 1 2008 PARTICIPANTES Fig 1 Carga nominal 2008 COMPARACION EN CARGA MAXIMA 1 50 A F P 1 2008 0 2 0 15 0 1 0 05 0 PARTICIPANTE Fig 1 Carga maxima 2008 ANEXO 2 SIM INTERNATIONAL COMPARISON OF 50 60 Hz ENERGY 2002 2007 SIM EM S2 SIM 1 4 COMPARISON Electric Energy El SNM particip en la comparaci n a 60 Hz 120 V 5 A para los factor
120. ose los campos de acci n sobre todo de la metrolog a legal inici ndose la metrolog a industrial a principios del a o 2000 La metrolog a el ctrica se inicia en el INTN a mediados del a o 2001 con un estudio que buscaba VIII Semetro Joao Pessoa PB Brazil June 17 19 2009 identificar las reas prioritarias as como los recursos necesarios para la atenci n de dichas reas 2 OBJETIVO En el presente trabajo se busca describir la evoluci n experimentada en el campo de la metrolog a el ctrica en el INTN desde el a o 2001 en que no se contaba con nada hasta la fecha Se describen cronol gicamente las actividades ejecutadas los resultados alcanzados los mecanismos utilizados para la implementaci n de las actividades as como el an lisis de los resultados m s importantes alcanzados Finalmente se presentan los proyectos en desarrollo a fin de dotar de una mayor y mejor capacidad de medici n en las magnitudes de mayor relevancia para el Paraguay 3 SITUACION EN EL A O 2001 En el a o 2001 el rea de metrolog a el ctrica no exist a en el INTN es decir no se contaba con personal adecuadamente preparado ni con la infraestructura m nima necesaria patrones equipos auxiliares y salas adecuadas para mediciones En ese a o se inician tratativas del INTN con el organismo del estado responsable por la generaci n transmisi n y distribuci n de la energ a el ctrica en el Paraguay ANDE por
121. r 2006 1 Oct 2006 1 Apr 2007 1 Oct 2007 Date Fig 4a Key comparison results from the pilot laboratory NIST and one participant INTI in the SIM EM K1 comparison for Thomas type resistor 1779992 corrected to 25 C 0 35 serial Number 1779885 1 amp vd E a E zo 0 40 Eu oe a p A F a gE 04s A EE _ 7 OF E A E g2 ha 3 0 50 FA eZ F 0 55 1 Oct 2005 1 Apr 2006 1 Oct 2006 1 Apr 2007 1 Oct 2007 Date Fig 4b Key comparison results from the pilot laboratory NIST and participant INTI in the SIM EM K1 comparison for Thomas type resistor 1779995 corrected to 25 C The first set of INTI results for this resistor in the first time period as shown in Fig 4a had significant drift and is not shown on the scale of this graph The results shown in Fig 4 illustrate several of the uses of the characterization process First is that each laboratory that participated in the comparison used measurement conditions normal to their own laboratory process The temperature characterization data made it unnecessary for all laboratories to measure the transport standards at 25 C instead they could use 20 C or 23 C as the laboratory oil bath temperature The additional uncertainty k 1 related to the temperature correction process was 0 032 uQ 0 when measurements were made at 20 C and 0 018 uQ 0 when measurements were made at 23 C The most important reason for characterization is to select resistors t
122. r is copper plated The energy dissipated in the heater resistor raises its temperature above the temperature of the solid copper body of the enclosure This incremental temperature change is measured by a thermopile which consists of approximately 100 junctions manufactured by partially copper plating a spiral of a constantan wire The thermopile wound on a square plexiglas rod is placed between two electrically insulating thermally conductive beryllium oxide washers The hot junctions washer is heated by the heater resistor the cold junctions washer is at the temperature of the copper mass of the enclosure The AC DC transfer difference of the reference arm of the CTVC at a frequency f Hz is calculated from Ocrvc J uel 1 1 VD where V tee f and V 1 are the AC voltages at the measurement reference plane that is at the middle of the tee at the frequencies f and 1 Hz It is assumed in 1 that the energy dissipated in the heater resistor as well as the voltage V at the resistor end of the coaxial line of the length l is the same for all frequencies and that the AC AC transfer difference referenced to 1 Hz is equal to the AC DC transfer difference The relation between the AC voltage V applied to the heater resistor terminating the coaxial line and the voltage V e at the reference plane of the tee i e the input of the line can be expressed by the transmission line equation Ve V cosh
123. r universal se encarga de medir la diferencia de frecuencia entre el GPSDO y reloj de rubidio Por ltimo el computador ejecuta un software desarrollado para este prop sito el cual se encarga de procesar los valores de diferencia de frecuencia medidos por el contador calcula la deriva del rubidio utilizando los valores registrados durante varias horas y estima la correcci n necesaria para mantener dicha variaci n de frecuencia en el entorno de 1x10 Hz Hz Una vez obtenido el valor de tensi n para corregir la frecuencia se env a la informaci n al microcontrolador para modificar la tensi n de control que ajusta la salida del rubidio La validaci n de este sistema se realizar mediante un sistema de seguimiento de frecuencia llamado SIM System Dicho equipo es parte de un sistema que el SIM Sistema Interamericano de Metrolog a est implantando con los Laboratorios Nacionales de las Am ricas y que permite el seguimiento on line de los patrones en dicha magnitud No es necesario sacarlos del pa s para calibraciones tal como ocurre con patrones secundarios en otras magnitudes Este equipo ya fue enviado a nuestro Laboratorio y se est n realizando las primeras evaluaciones del comportamiento del sistema en tiempo real Los primeros resultados son alentadores aunque no colman totalmente nuestras expectativas Con el correr de los d as tendremos informaci n suficiente como para evaluar y posiblemente realizar ajustes en el al
124. rce to be obtained from the time base of the digitizer used to sample the voltage signals 5 This allows the sampling interval to be selected according to the time base resolution of the digitizer so that each acquisition can cover one or more signal periods with high accuracy In 4 the voltage drops across the resistors are measured It is not easy to measure such voltage drops with digital sampling voltmeters A complex buffer arrangement is required to unload the digitizer inputs Wagner balancing is also required to reduce the potential differences between the LOW terminals of the impedances and earth so that their influence on the impedance ratio can be negligible In addition the approach requires the digitizer to be synchronized to the signal generator A new approach for calibrating automated high voltage current comparator based bridges is presented here It leads to larger uncertainties but is slightly easier to implement For the calibration two sinusoidal currents are synthesized with two synchronized signal generators and two resistors and injected into the bridge inputs Again the capacitance ratio and dissipation factor simulated by these currents are calculated from an ac voltage ratio estimated from the digitized data together with the impedance ratio of the resistors In contrast with 4 synchronization circuits are not required between the digitizers and the generators as the algorithm in 6 is used to design the
125. re total de la calibraci n mediante la medici n de la frecuencia m s alta disponible en el objeto con lo cual se reduce la incertidumbre por la resoluci n del sistema de medici n y la reacci n manual del operador Fue realizado en el Laboratorio Metrol gico de Variables El ctricas LMVE del Instituto Costarricense de Electricidad como proyecto de graduaci n de Johnny Jim nez para optar por el grado de Licenciatura en Ingenier a Electr nica 3 METODO La Figura 1 muestra la se al medida con un osciloscopio de un par de placas met licas que contienen en medio el cron metro objeto de la calibraci n todo esto dentro de una c mara blindada Se nota que esta se al es muy ruidosa si se requiere medir la frecuencia de la se al b sica del oscilador de cuarzo En la referencia 3 Trigo y Slomovitz calculan varias frecuencias derivadas de la fundamental del oscilador de cuarzo A partir de estas derivadas implementan el sistema medidor en frecuencias de por ejemplo 28 Hz 32 Hz y 42 Hz que corresponden a los pulsos de mayor amplitud en la Figura 1 La frecuencia 215 Hz queda cubierta por estas componentes y no se puede medir directamente por estar cercana al nivel de ruido de la se al total Figura 1 Se al relacionada con la inducci n de campo de un cron metro en las placas conductoras El diagrama de bloques del sistema implementado se muestra en la Figura 2 Ean GPIB Seria pom e idas de daok pubomalrado
126. reover if w T is small we can take cos w T 1 and sin w T w tg Thus E can be written as E wr sin f 11 It can be seen that the error depends on the phase angle Taking four measurements with different angles B the time delay can be calculated Fig 2 shows the connections for the four measurements P denote power N denotes that the switch is in Normal position and R in reverse position Channel A of the source is used as reference and channel B as V or Vg 1 PN90 the reference is connected to channel 1 and B 90 2 PR90 the reference is connected to channel 2 and the variable to channel 1 and B 90 3 PN270 the reference is connected to channel 1 and B 270 4 PR270 the reference is connected to channel 2 and the variable to channel 1 and B 270 With this procedure the time delay between the two DMM can be calculated Table 2 shows the values for the four measurements and the calculated delay between the VIII Semetro Joao Pessoa PB Brazil June 17 19 2009 DMMs using a two channel source HP3245 and the output of each channel was setting in 1 V Table 2 Power measurements for determining the time delay between the two DMM PN90 PR90 PN270 PR270 i S The value obtained for the time delay between the two DMM using the method described above was 475 ns It confirms to the value obtained with the software 2 3 VOLTAGE CHANNEL In the voltage channel a two stage v
127. res iguales conectados en serie siendo posible acceder a cada uni n individual 2 Sean R los valores de las resistencias individuales El promedio Z de todas las ca das de tensi n producidas por la circulaci n de una corriente vale 10 IDR _ 1 10 Z 4 donde es la corriente por la serie Por otro lado la suma de las ca das vale 10 VaR 5 1 Por tanto la relaci n Y Z vale 10 exactamente En esto se basa el principio del divisor Para la comparaci n de tensiones se usa un voltimetro de alta precisi n HP 34584 8 12 d gitos en las escalas de 10 V para la suma total y 1 V para las ca das individuales Obs rvese que no es necesario conocer los errores de dicho instrumento pues s lo se usa en calidad de comparador El nico requisito que afecta esta medida es su estabilidad Es m s el propio procedimiento calibra al volt metro en lo concerniente a la relaci n 10 1 en las escalas usadas El divisor resistivo posee un divisor de guarda como lo muestra la Fig 3 y si es necesario se conecta la guarda del voltimetro a cada salida de guarda correspondiente a la salida de tensi n usada En caso que esto no fuera necesario puede usarse la guarda general del divisor borne G Una sencilla prueba permite determinar la influencia de la conexi n de guarda Durante el comienzo de la medici n se cambia la guarda de lugar y se observa la variaci n en el instrumento Realizando esta prueba en el resistor
128. ritmo b sico de Swerlein a LabVIEW aplicando algunas modificaciones al mismo Posteriormente se utiliz LabVIEW y la ayuda de MatLAB en el procesamiento de los datos para implementar la versi n extendida del algoritmo de Swerlein mediante el cual se facilita el c lculo de la potencia el ctrica VIII Semetro Joao Pessoa PB Brasil Junio 17 19 2009 Previo al c lculo de la potencia se realizaron diversos ensayos para lograr la sincronizaci n de ambos mult metros 3458 A La segunda etapa montaje y configuraci n de los equipos inicia con la adquisici n de dos equipos el divisor inductivo de tensi n y el convertidor de corriente a tensi n con resistencia patr n incorporada ambos equipos marca CONIMED En esta etapa se logra el acople en cuanto al software y hardware se refiere lo cual permite ajustar algunos detalles del programa en b squeda de su ptimo funcionamiento En la etapa de prueba y validaci n se abarcan las conexiones entre los equipos que conforman el sistema de medici n de nuestro patr n de potencia el ctrica resaltando la ubicaci n de la tierra para el circuito de corriente en el equipo que present menor ca da de potencial Por otro lado la validaci n del software se desarrolla mediante un ejercicio de comparaci n con el Instituto nacional de tecnolog a industrial INTD En la Fig 2 se observa los equipos que conforman el sistema de medici n del patr n de potencia el ctrica del CENAMEP ju
129. roviders for a number of years and a third is soon likely to begin operation To execute its responsibility for establishing an adequate measurement system for this market and in recognition of the specifics of local circumstances TTBS is seeking to move progressively forward with a cooperative approach By forming cooperative partnerships in concert with the regulatory authorities and other established stakeholders TTBS is attempting to harmonize its intervention so as to minimize inconvenience to suppliers while at the same time implementing a system which ensures that the consumers and society get value for money Market efficiency is a particularly important reason for the intervention in this area of measurement since there are potentially many long term benefits to the environment and for the industrial competitiveness of the national economy The current standards for power measurements at TTBS are the Fluke 5720 Multi function and Fluke 5500 Multi product Calibrators However in collaboration with our industry partners TTBS will acquire a calibration bench and establish a sampling regime for the objective calibration verification of power and energy meters The hardware and training for this system are currently being sourced Once this consumption based measurement infrastructure has been established 1t will server as a platform for examining supply quality and loss reduction measurements The overall objective is to establ
130. s aceptados internacionalmente para poder brindar el servicio de calibraci n de son metros clase 1 y 2 El Laboratorio de Electricidad lo vemos con m s detalle en el punto siguiente 2 1 LABORATORIO DE ELECTRICIDAD Nuestro Laboratorio de Electricidad cuenta con patrones tanto en corriente continua y alterna como en energ a Nuestros patrones tienen trazabilidad al NIST en energ a a trav s de los patrones de Radian Research y en corriente continua y alterna a trav s de los patrones de Fluke Los principales patrones que tenemos son en energ a contadores Radian monofasico RD 21 de exactitud 0 02 y trif sico RD 31 de exactitud 0 02 en corriente cont nua y alterna un calibrador multifunci n Fluke 5520 A y mult metro Fluke 8508 A de 8 2 d gitos 732A DC Referente Standard Fluke y un Transvolt 9154D Guildline Brindamos los siguientes servicios Calibraci n de instrumentos en corriente continua y alterna tales como amper metros voltimetros ohmmimetros resistencias el ctricas megohmmetros telur metros simuladores medidores pinzas multim tricas y mult metros hasta 5 2 d gitos en potencia y energ a calibramos vat metros medidores de energ a a inducci n clase 2 y est ticos hasta clase 0 25 patrones de energ a con exactitud hasta 0 025 y equipos de ensayo de medidores de energ a el ctrica Evaluaci n de modelo de medidores de energ a el ctrica a inducci n Evaluaci n de caracter sticas
131. scopio que permiten visualizar las formas de onda tensi n corriente para fines de diagn stico 1 2 CAMBIO DE CHIP El chip de 10 V present un problema conocido como offset inducido por microondas se trata de un problema en los contactos el ctricos entre las terminales del chip y el conector de los cables de entrada salida El contacto se hace usando un conector en forma de peque o peine hecho de BeCu recubierto de oro que hace los contactos a presi n con las terminales del chip Cuando la conexi n no es buena el contacto act a como un diodo que rectifica la se al de microondas y produce un Offset sumado a la tensi n de salida que puede verse como una fem t rmica Sin embargo a diferencia de una fem t rmica el offset inducido por microondas desaparece al apagar las microondas El offset medido fue de 2 5 uV Este offset puede ser cancelado con la t cnica de cambio de polaridad utilizada en este tipo de mediciones pero si no es estable en el tiempo la cancelaci n no es buena ocasion ndose un incremento en la incertidumbre del patr n La manera usual de corregir este problema es mover ligeramente el peine para mejorar los contactos al hacerlo se da aron las pistas del chip y ste qued inservible Decidimos sustituir el chip por uno con tecnolog a del PTB marca PREMA el cual result totalmente compatible con el sistema desarrollado en el NIST la nica diferencia que observamos fue
132. sistema SIM de medici n tiempo y frecuencia Una vez puesto en funcionamiento y comparaci n en tiempo real con los dem s relojes de toda Am rica el INTN podr iniciar el desarrollo de su Escala de Tiempo el cual se podr utilizar para establecer la Hora Oficial en la Rep blica del Paraguay Desde la vista del especialista del CENAM el Sistema SIM del INTN viene activando en la red de Tiempo y Frecuencia del SIM www tf nist gov sim enviando sus datos de mediciones con lo cual se busca establecer la estabilidad repetibilidad desviaci n e incertidumbre del sistema de medici n de tiempo a fin de que el sistema sobre el cual se depositar la responsabilidad del establecimiento y mantenimiento de la hora oficial demuestre la necesaria confiabilidad 6 3 Adquisici n de multicalibrador Para mediados de a o 2009 se tiene prevista la apertura de ofertas para la adquisici n de equipos multicalibradores tipo Fluke con el objetivo de dar trazabilidad a los equipos multimetros voltimetros amper metros Ohmetros etc Este servicio tiene una alta demanda en el sector el ctrico nacional considerando que actualmente las empresas que precisan de estas calibraciones deben gestionarlas en el exterior del pa s lo que encarece el servicio y en muchos casos hace poco posible sobre todo en el caso de peque as empresas Con la implementaci n de estos servicios se busca tambi n ampliar el mbito de actuaci n del INTN en el
133. spheric pressure at sea level For an unsealed Thomas type resistor this effect results in a resistance change of 0 5 wO Q at an altitude of 2000 m In precise measurements it is necessary also to correct for the pressure of oil above a resistor as well as normal variations in atmospheric pressure 4 SIM COMPARISONS Two 1 Q transport standards listed in Table 1 were selected to use in the SIM EM KI comparison based on their low pressure coefficients and stable temperature characteristics The resistance values from this comparison shown in Fig 4a and 4b illustrate a successful application of the temperature characterization process The NIST measurements were made with the resistors at 25 C INTI Instituto Nacional de Technolgia Industrial Argentina uses 20 C for the normal measurement process and so made all measurements at 20 C and corrected the results to equivalent 25 C values using the 2005 data from Table 1 This difference in the measurement process required that temperature corrections of order 24 3nQ OL Fig 4a and 23 8 uQ O Fig 4b be applied to the INTI data Better agreement would be evident in Fig 4b if the correction for temperature had been made using the average of 2005 and 2008 temperature coefficients for standard 1779885 1 25 serial Number 1779882 1 02 1 30 1 35 e iiy 1 40 Resistance Correction from Nominal Adjusted to Temperature 25 C p a 1 49 1 Oct 2005 1 Ap
134. st of four 4 Fluke 732B Solid State Zener Diode Voltage standards In addition we disseminate DC voltage using Fluke 5720 and 5500 Calibrators We do not envision acquiring a Josephson Array however we will likely acquire at least two 2 additional solid state standards and appropriate DC Voltage Dividers to reduce our uncertainties for dissemination and recalibrate our calibrators in house Where feasible we always seek to improve our capabilities Our standards for Current would be derived from our improved DC Voltage and Resistance standards capabilities 2 2 Resistance Metrology Resistance metrology thus far has been developed to support the calibration of industrial instruments Currently our highest level resistance standards are obtained from a Fluke 5720 Multifunction Calibrator In order to raise measurement capability in this area we will seek to acquire a series of suitable resistance standards 1 10 100 1k 10k 100k 1M amp 10 MQ in oil and or air This development is particularly important since we are also intent on enhancing our temperature measurement capability We will also seek to acquire an AC and or DC Bridge calibrators and other artifact resistance standards necessary for proper dissemination of resistance traceability VIII Semetro Joao Pessoa PB Brazil June 17 19 2009 and accuracy at the levels required for adequate electrical and temperature measurements 2 3 Time and Frequency Me
135. stry Applications v 1 pp 386 391 Athens Sep 29 Oct 1 2004 11 Agilent 33250A 80 MHz Function Arbitrary Waveform Generator User s Guide Ed 2 Aug 2002 12 U Pogliano Use of integrative analog to digital converters for high precision measurement of electrical power IEEE Trans Instrum Meas 50 no 5 pp 1315 1318 Oct 2001 13 R L Swerlein A 10 ppm accurate digital ac measurement algorithm Proc NCSL Workshop and Symposium Albuquerque Aug 1991 pp 17 36 Available http www agilent com 14 G A Kyriazis and M L R Campos Bayesian inference of linear sine fitting parameters from integrating digital voltmeter data Meas Sci Tech 15 pp 337 346 Feb 2004 Erratum pp 1047 15 G A Kyriazis An orthogonal design of experiments for accurately estimating harmonics of low frequency periodic signals IEEE Latin America Transactions 6 no 1 pp 1 8 Jan 2008 In Portuguese 16 W J M Moore and K Ayukawa A current comparator bridge for power measurement IEEE Trans Instrum Meas 25 pp 550 553 Dec 1976 17 G A Kyriazis N M Oldham and M Werneck A current comparator based bridge for calibrating power and energy standards at 50 60 Hz CPEM Digest Ottawa Canada Jun 2002 pp 256 257 18 BIPM IEC IFCC ISO IUPAC IUPAP and OIML 1995 Guide to the expression of uncertainty in measurement Geneva Switzerland International Organizatio
136. t 1 V long time constant 15 s and a close coupling of the cold junctions of the thermopile to the enclosure which increases its sensitivity to the changes of the ambient temperature The experience of this comparison has shown that it usually requires modifications in the ac dc automatic comparator software and close attention to a good thermal insulation from the ambient to obtain satisfactory results on the CTVC Consequently the standard deviations of typical tests were in the range of a few uV V much higher than in tests of a vacuum junction thermal converter The uncertainty budget of the frequency characteristic of the CTVC includes uncertainty of the determination of the mechanical dimensions coaxial line length and inner and outer diameters uncertainty of the electrical parameters radiation losses uncertainty of the thermal correction uncertainty associated with the design variations and mechanical assembly Components of the uncertainty originating in the uncertainty of the mechanical dimensions were evaluated by recalculating the theoretical frequency characteristic while individually varying the investigated parameter A change in the characteristic with the change of the parameter was then used to estimate the standard uncertainty of this error source Other components of the uncertainty were estimated experimentally The design variation uncertainty was estimated by comparing experimental disagreements between different re
137. tema de medici n Tabla 1 Desviaci n est ndar obtenida antes de las modificaciones hechas al programa Se observa una gran variaci n del Error entre 4 y 111 ppm Primera Medici n Realizada Contra el PRS200 3 Tensi n V Corriente A Angulo I I I I I I I I I I Tabla 2 Desviaci n est ndar obtenida despu s de las modificaciones hechas al programa Sengunda Medici n Realizada Contra el PRS200 3 0 5 CONCLUSIONES Las pruebas practicas y comparaciones efectuadas hasta el presente son promisorias ya que se ha logrado mejorar el desvio de las mediciones del PPEAE desde un valor inicial 50 ppm a un desv o medio est ndar por debajo de 18 ppm Hablamos de promisorias ya que falta realizar una mayor cantidad de pruebas en diversos puntos de corriente y tensi n los cuales permitir n caracterizar de forma completa el sistema de medici n que conforma nuestro futuro PPEAE Adicionalmente queda por validar los errores correspondientes a la referencia del INTI utilizada como patr n de potencia el ctrica y adicionalmente pretendemos realizar intercomparaciones con otros INM que actualmente desarrollan o han desarrollado otros proyectos similares Todo lo anterior est enfocado en la alta exactitud que se pretende alcanzar en las mediciones de potencia el ctrica mejor que 50 ppm tal como se hab a propuesto en este Proyecto y as poder considerar el PPEAE como el futuro Patr n Nacional de Potenc
138. the Inter American Metrology System SIM and the Instituto Nacional de Metrologia Normaliza o e Qualidade Industrial Inmetro We sincerely hope that the SIM Training and Development on Electrical Metrology will satisfy the needs of the participants We wish you all participants and accompanying persons a very pleasant stay in Joao Pessoa Brazil Gregory Kyriazis Chair SIM Training and Development on Electrical Metrology We compiled below the technical papers that have been presented by most of the members of the SIM Electricity and Magnetism Metrology Working Group SIM EM MWG during the VIII International Seminar on Electrical Metrology VIII SEMETRO Digital copies of these technical papers were also included in the CD of VII SEMETRO This booklet was elaborated to stimulate the discussion among the SIM members The papers are listed in the order they appear in the Technical Program of VIII SEMETRO LIST OF TECHNICAL PAPERS Wednesday June 17 Trinidad and Tobago Bureau of Standards TTBS Trinidad and Tobago Francis Hamilton Developing electrical metrology in Trinidad and Tobago Session WB1 15h20min Instituto Costarricense de Electricidad ICE Costa Rica Harold S nchez et al Calibraci n de cron metros mediante la medici n de la frecuencia del oscilador de cuarzo Poster Session W 16h30min 18h00min Servicio Nacional de Metrolog a Instituto Nacional de Defensa de la Competencia y
139. the current capabilities and future developmental plans for Electrical Metrology in Trinidad and Tobago Low frequency electrical metrology is specifically highlighted since the categories of this aspect of electrical metrology are fundamental to building an adequate electrical measurement infrastructure The five main categories of electrical measurement services emphasized are dc voltage resistance time and frequency impedance and electric power and energy since these are considered of most importance at this time in the developmental process Keywords Electrical Metrology National Measurement System Low Frequency DC Metrology Electrical Measurement Infrastructure 1 INTRODUCTION Metrology in Trinidad and Tobago developed from Colonial Legislation which existed in 1878 Following this the Weights and Measures Ordinance of 1935 was in effect After independence in 1962 an attempt was made through a Metrication Board to convert the national measurement system from imperial to metric between 1969 and 1987 The Trinidad and Tobago Bureau of Standards TTBS was formed in 1973 and the responsibility for metrification was passed from the Metrication Board to TTBS in 1987 At that time the Metrology Section formed a part of the Testing Division of TTBS until the Metrology Act of 2004 was passed The Metrology Act 2004 made TTBS responsible for establishing and maintaining the measurement system in Trinidad and Tobago In 2006 the M
140. their product specifications TABLE VIII CAPACITANCE RATIO Cy Cs rep UCCx Cs rep Reading of k 2 bridge 1 1 000257 0 000084 1 0003 1 999725 0 000086 1 9997 3 00145 0 00016 3 0014 4 00039 0 00013 4 0004 5 00078 0 00019 5 0008 6 00040 0 00017 6 0003 6 99893 0 00019 6 9989 8 00187 0 00030 8 0019 9 00287 0 00041 9 0029 9 99803 0 00031 9 9980 Dy 1 10 and Isl 0 2 mA TABLE IX DISSIPATION FACTOR Dyref U Dx Reading of k 2 bridge 1 0 000004 0 000014 0 00001 0 000022 0 000014 0 00004 0 000105 0 000016 0 00012 0 000998 0 000016 0 00100 0 010002 0 000021 0 00995 0 099992 0 000029 0 09943 1 00008 0 00085 0 99779 Cx Cs 1 1 and l s 0 2 mA TABLE X CAPACITANCE RATIO Cy Cs reep UCC x Cs rep Reading of k 2 bridge 2 1 000277 0 000025 1 000274 1 999839 0 000032 1 999854 2 99979 0 00010 2 999801 4 000175 0 000070 4 000179 5 00033 0 00013 5 000291 6 00002 0 00029 5 999980 6 99892 0 00026 6 998971 7 99731 0 00038 7 997351 8 99325 0 00041 8 993379 9 99735 0 00048 9 997315 Dy 1 10 and l s 0 2 mA TABLE XI DISSIPATION FACTOR Dyget U Dxrer Reading of k 2 bridge 2 0 000009 0 000012 0 000009 0 000010 0 000012 0 000012 0 000098 0 000012 0 000096 0 000987 0 000016 0 000984 0 009994 0 000012 0 009958 0 100020 0 000024 0 099679 Cx Cs 1 1 and Isl 0 2 mA VIII Semetro Jo o Pessoa PB Brazil June 17 19 2009 TABLE XII CAPACITANCE RATIO Cx Cs rep UCC x Cs rer Reading o
141. tion capacitance to ground C4 and therefore a very stable and reproducible value for this capacitance is necessary after reassembling the standard or changing the series conductance box It is desirable to keep the combined stray junction capacitance C34 as small as possible relative to Cj The dissipation factor standards should have stable values of dissipation factor tanx and capacitance C3 as defined by 5 and 6 respectively A highly stable capacitance Cp should be used A gas dielectric hermetically sealed three terminal standard capacitor with nominal value of 1000 pF was chosen This capacitor has GR874 connectors The direct capacitance Cj of the standard capacitor was determined at 400 Hz 800 Hz 1 kHz and 1 6 kHz with an accurate coaxial capacitance bridge 9 The value at 60 Hz was predicted to be 999 992 0 002 pF using regression techniques 10 The resistors should be stable with a temperature dependence of less than 10 C and have negligible time constant at 50 60 Hz time constant less than 10 s The resistance values should be selected to match the measured capacitance values C gt and Cy4 and produce the desired tan x from 5 Five conductance boxes were built Four of them contain hermetically sealed H type Vishay precision resistors with the nominal values 100 Q 500 Q 5 kQ and 50 kQ One box contains a 294 kQ metal film resistor Each nickel plated conductance box has dimensions 35 x 35 x 75 mm
142. to allow the thermal converter to thermally stabilize in each of the three measurements 2 Another disadvantage is that the thermal wattmeter cannot measure power of individual harmonics because the thermal converter measures the heat dissipated by the sum of all the frequencies To face these problems we developed a sampling wattmeter It uses two digital multimeters DMM sampling in DC asynchronously with the signal 4 5 2 DESCRIPTION OF THE INSTRUMENT Fig 1 depicts a diagram of the system use at INTI as a sampling wattmeter As power supply we use a two channel source like Fluke 6100A or Zera VCS320 These sources can drive voltage and current in each channel at different power factors Current and voltage are applied directly to the Unit Under Test UUT At the current input of the sampling wattmeter there is a multirange current transformer CT 10 0 1 A O 1 A A resistor of 10 Q is connected to the secondary of the CT Thus we get a voltage of 1 V under nominal conditions In the voltage channel a multirange 240 120 60 6 V voltage transformer VT is used For sampling the signals two digital multimeters DMM Agilent 3458A in the master slave configuration in the 1 V and 10 V range are used VIII Semetro Jo o Pessoa PB Brazil June 17 19 2009 A computer controls the multimeters and the CT and VT ranges DMM Master y vr Fig 1 Scheme of the sampling wattmeter Both signals are sampled by the DMM
143. torios se han desarrollado sistemas automatizados que miden submultiplos de la frecuencia del oscilador de cuarzo 2 Hz 32768 Hz como por ejemplo la frecuencia de refrescamiento de la pantalla considerando que el nivel de la se al relacionada con el refrescamiento es de un nivel relativamente alto El nivel de la frecuencia 2 Hz es muy bajo y est cercano al umbral de ruido de la se al total Para su detecci n es necesario filtrar y amplificar la frecuencia deseada lo cual es dif cil en el nivel de ruido presentado por otras componentes de la se al total El m todo presentado en este art culo hace uso de amplificador diferencial una etapa de filtrado y de reducci n de los pulsos generados por las se ales cuadradas de submultiplos de la frecuencia b sica y una etapa de reconstrucci n de la se al de la frecuencia b sica El uso de este sistema permite la medici n de la frecuencia del oscilador de cuarzo disminuyendo la incertidumbre por la resoluci n de la medici n de frecuencia la cual es la componente mayor en el sistema total El presente trabajo se diferencia de otros realizados con el mismo prop sito 1 3 en que la frecuencia medida es la del oscilador del cron metro no otras componentes de m s baja frecuencia como la de refrescamiento de la pantalla 2 PROP SITO Este sistema de calibraci n fue implementado con el prop sito de automatizar la calibraci n de cron metros y de reducir la incertidumb
144. trica En febrero de 2003 se firma el Convenio Marco ANDE INTN y en julio de 2003 se firma el T rmino de Referencia espec fico para la implementaci n de las etapas de Aprobaci n de Modelo y Verificaci n Primitiva de medidores de energ a el ctrica mediante el cual se realiza un control coordinado entre ambos organismos estatales VIII Semetro Joao Pessoa PB Brazil June 17 19 2009 El T rmino de Referencia constituye la base operativa de los controles ya que establece los siguientes puntos Antecedentes del trabajo conjunto los servicios de control metrol gico costos de los servicios y forma de pago lugar de la prestaci n de los servicios equipo interinstitucional plazo de ejecuci n y otros aspectos legales En el punto referente al equipo interinstitucional se fija que el mismo es responsable por el seguimiento control y evaluaci n de las actividades enmarcadas en el T rmino de Referencia as como es encargado de administrar el Convenio Marco Tambi n el Termino de Referencia establece que todo oferente solo puede ofertar a la ANDE medidores que tengan el modelo aprobado por el INTN en cualquiera de las modalidades de compra establecidos en ley de contrataciones p blicas del Estado Tambi n mediante dicho acuerdo espec fico se establece que el INTN realizar la verificaci n primitiva en f brica de los lotes de medidores que la ANDE haya adquirido detallando las Ambas etapas se realzan tomando
145. trolog a de la Rep blica del Paraguay 1 982 2 Decreto del Poder Ejecutivo que Reglamenta la Ley Nacional de la Rep blica del Paraguay 1 999 3 Norma UNE EN 60 514 Control de aceptaci n de los contadores de corriente alterna de clase 2 1996 4 Norma UNE EN 60 521 Contadores de inducci n de energ a activa para corriente alterna de clases 0 5 1 y 2 1996 5 International Standard IEC 1358 Acceptance inspection for direct connected alternating current static watt hour meters for active energy classes 1 and 2 1996 6 International Standard IEC 62052 11 Electricity metering equipment AC General requirements test and test conditions Part 11 Metering equipment 2003 7 International Standard IEC 62052 21 Electricity metering equipment a c Particular requirements Part 21 Static meters for active energy classes 1 and 2 2003 ViitSemetrO El patron de efecto Josephson del CENAM experiencias en 15 anos de uso y oa si ds P 2 David Avil s 7 Dionisio Hernandez Enrique Navarrete i CENAM Quer taro M xico caviles cenam mx a CENAM Quer taro M xico dhernand cenam mx i CENAM Quer taro M xico enavarre cenam mx Resumen Este trabajo sintetiza algunas de las experiencias en el uso del patr n de efecto Josephson del CENAM as como algunas modificaciones hechas al mismo con el prop sito de disminuir su susceptibilidad al ruido electromagn tico Palabras clave
146. trology We recently acquired two GPS Disciplined Oscillators Rubidium and Crystal as our Time and Frequency Standards We intend to utilize these new standards to disseminate accurate time and support our services in the areas of time and frequency dissemination calibrations and measurements We expect to soon link our Rubidium Standard to the SIM Time Standard Network via a NIST or SIM Common View Time and Frequency Measurement System 2 4 Impedance Metrology Our immediate plans for this aspect of Low Frequency DC Metrology are to attain an acceptable minimum capability in accordance with our actual and expected needs as our circumstance requires Our standards in this area currently include Fluke Multi function and Multi product calibrators as well as an Agilent LCR Meter In the future we will likely seek to acquire standard capacitors inductors and an appropriate impedance bridge to reduce our uncertainties to the level required by the national economy as well as participate in regional and or international inter comparisons 2 5 Electrical Power and Energy Metrology We have limited experience in these areas of metrology However there is major energy consumption in Trinidad and Tobago particularly in some current and future heavy industries and manufacturing concerns In 2007 Trinidad and Tobago produced some 7 704 billion kWh of electricity energy and consumed 7 083 billion kWh The two local power suppliers have been p
147. ue puedan establecer peque os laboratorios de ensayos a trav s de los cuales se pueda descentralizar el control de los medidores de energ a el ctrica espec ficamente para esta etapa del control metrol gico Para ello y a la fecha se han firmado convenios de cooperaci n con dos facultades nacionales con quienes se viene trabajando en la determinaci n de los recursos e infraestructura necesarios para el inicio de las actividades 6 2 Establecimiento del patr n nacional de tiempo y frecuencia El INTN ha recibido en diciembre de 2008 un sistema de medici n de tiempo desarrollado por especialistas del Grupo de Trabajo de Tiempo y Frecuencia T amp FWG del Sistema Interamericano de Metrolog a SIM El sistema consta de un receptor GPS de 8 canales acoplado a un reloj de rubidio que act a como contador de intervalos de tiempo Ambos dispositivos est n acoplados a una computadora que procesa y almacena los resultados de las mediciones Los objetivos que persigue el INTN con dicho sistema son a tener una referencia de tiempo y frecuencia para entrar a desarrollar un patr n propio de potencia y energ a y b desarrollar una escala de tiempo y diseminar la hora exacta en Paraguay Del 16 al 21 de febrero del corriente a o el Dr Eduardo de Carlos especialista del Laboratorio de Tiempo y Frecuencia del Instituto de Metrolog a de M xico CENAM estuvo en el INTN para la puesta en marcha y capacitaci n en mantenimiento del
148. ular con la fuente original era muy dif cil seleccionar un escal n en particular por lo que se modific el circuito a adiendo un potenci metro que facilita el ajuste fino de la tensi n de polarizaci n para ajustarla a un nivel cu ntico deseado 4 MEJORANDO LA ESTABILIDAD DEL PATR N Los patrones de efecto Josephson basados en chips con tecnolog a SNS tienen uniones Josephson hister ticas de alta capacitancia y son intr nsecamente inestables ya que tienen anchos de escal n del orden de 20 uA es decir que ruidos producidos por el sistema de medici n o generados en el laboratorio pueden hacer cambiar el nivel cu ntico del patr n con gran facilidad Es usual que durante una medici n utilizando este tipo de patrones se tengan varios saltos de escal n espont neos es decir cambios en el nivel cu ntico Cuando estos saltos de escal n ocurren es posible detectarlos desechar algunas lecturas y recalcular el valor de la tensi n del patr n o nivel cu ntico y seguir la medici n En la calibraci n de referencias electr nicas en base a diodos Zener si estos cambios son menores a 1 mV los errores producidos por la ganancia del detector de nulos son despreciables Sin embargo en otras aplicaciones como en la calibraci n de VIII Semetro Jo o Pessoa PB Brazil June 17 19 2009 pilas patr n estos cambios de nivel de la tensi n de salida son indeseables Para incrementar la estabilidad e inmunidad del patr n
149. una exactitud mejor que SOppm es que se puede mantener en estado de calibraci n con trazabilidad internacional las mediciones de energ a y potencia el ctrica en la cadena nacional de mediciones sin necesidad de recurrir peri dicamente a otros INM del exterior Los principales beneficiarios con el desarrollo de este proyecto son todos los consumidores de energ a el ctrica en Panam residenciales comerciales e industriales al asegurarse que las mediciones del consumo de sus residencias O instalaciones se realicen con la exactitud internacionalmente aceptada establecida por los Reglamentos existentes en Panam Tambi n ser n beneficiarias las Empresas que generan transmiten y distribuyen energ a el ctrica ya que las transacciones entre ellas estar n garantizadas con transparencia y equidad a trav s de la acci n del CENAMEP AIP actuando como el Laboratorio Nacional de Referencia para Magnitudes El ctricas declarado como tal por la Autoridad Nacional de los Servicios P blicos ASEP 4 METODOS Y RESULTADOS El patr n de potencia el ctrica de alta exactitud de nuestro centro se desarroll durante tres etapas e Etapa de programaci n e Etapa de montaje y configuraci n de los equipos e Etapa de prueba y validaci n La etapa de programaci n fue desarrollada en su totalidad utilizando el software de programaci n gr fica LabVIEW de National Intrument iniciando con la transcripci n del programa en BASIC del algo
150. vol 46 pp 365 368 1997 5 S Filipski R F Clark D C Paulusse Calorimetric Thermal Voltage Converter as a Wideband Calculable Standard of AC DC Difference IEEE Trans Instrum Meas vol 48 pp 387 390 1999 6 P S Filipski R F Clark D C Paulusse Calibration of HF Thermal Voltage Converters using an Asymmetrical Tee IEEE Trans Instrum Meas vol 50 pp 345 348 2001 7 CJ van Mullem E F Dierikx J P M de Vreede Key comparison CCEM K6 c of AC DC voltage transfer standards at selected frequencies between MHz and 100 MHz Final report February 2005 WWW bipm org utils common pdf final_reports EM K6 CCEM K6 c pdf 8 P S Filipski M Boecker Improvements in the AC DC Current Transfer Capabilities at NRC Digest of the Conference on Precision Electromagnetic Measurements CPEM 2004 London UK June 27 July 03 2004 pp 579 580 9 P S Filipski C J van Mullem D Janik M Klonz J R Kinard T E Lipe B C Waltrip Comparison of High frequency AC DC Voltage Transfer Standards at NRC VSL PTB and NIST IEEE Trans Instrum Meas vol 50 pp 349 352 2001 MIIHSemetrO TRANSPORT BEHAVIOR AND CHARACTERIZATION OF PRECISION 1 Q RESISTORS FOR INTERNATIONAL COMPARISONS R E Elmquist G R Jones and B J Pritchard National Institute of Standards and Technology Gaithersburg MD 20899 8171 USA elmquist nist gov National Institute of Standards
151. y in nonsinusoidal situations Since 1992 he is with the Electrical Standards Group where his research is aimed at the high precision ac dc transfer measurements Daniel Slomovitz Administraci n Nacional de Usinas e Transmisiones El ctricas UTE Montevideo Uruguay Daniel Slomovitz was born in Montevideo Uruguay in 1952 He received the Electric Engineer and the Dr Eng degrees from the Universidad de la Republica del Uruguay Montevideo He is a Professor at the same university teaching on Electrical Measurements In 1977 he joined the Laboratory of UTE National Power Utility Uruguay and now he is the Head of the Laboratory He has performed researches in low frequency electrical measurements and high voltage testing publishing more than 100 papers and the books Mediciones El ctricas IEEE and Gu a sobre Redacci n T cnica His areas of researches include impulse and partial discharge high voltage tests power measurements current and voltage transformers among others Tutorial Notes All participants in the SIM T amp D on Electrical Metrology received the training material according to the specific module he or she was registered The list of Modules are provided below Module 1 Mediciones de Tensi n El ctrica Continua de Alta Exactitud David Avil s tutorial notes with 99 pages in color Module 2 DC Resistance Measurements Randolph Elmquist tutorial notes with 179 pages in color Module 3 AC DC Thermal

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