Daniel Slomovitz

Shielded electronic current transformer

A current transformer with nominal ratio 10 A to 10 mA, intended for low-frequency applications, was developed. It includes an electronic device to reduce the magnetizing current, and a continuous shield in the secondary winding (coaxial cable) in order to eliminate the effect of stray capacitances. No guard-source is connected to the shield. It is proposed in this paper to leave the cable-shield-potential floating. This leads to high-accuracy results (ratio errors and phase-displacements in the order of few parts in 10/sup 6/ from 50 Hz to 1 kHz).

Trilateral South-American project: a reference system for measuring electric power up to 100 kHz - progress report

Three countries in South America are jointly developing a reference system for measuring electric power up to 100 kHz. The objective is the construction of three similar measuring systems, one for each institute. The measuring system and the current status of the development of its modules are described here. This project will contribute to provide calibration services in measuring ranges still not covered by the three institutes both in ac-dc transfer and in electric power.

Resistor dividers for power quality meters

In this paper, a proposal to reduce the influence of stray capacitances and non-linear effects on resistors used for voltage dividers up to 1000 V and 100 kHz is presented. A novel type of shield is proposed which avoids the use of guarding arms.

Multilateral Comparison of Electrical Power, Between the National Laboratories of Germany, Argentina, Brazil and Uruguay

It is presented in this paper the results of a comparison in Electrical Power, between the National Laboratories of Germany: Physikalisch - Technischen Bundesanstalt (PTB), Argentina: Instituto Nacional de Tecnología Industrial (INTI), Brazil: Instituto Nacional de Metrología, Normalizaçao e Qualidade Industrial (INMETRO) and Uruguay: Usinas y Trasmisiones Eléctricas (UTE), carried out during 2004. The instrument used as traveling standard was a power standard belonging to the PTB. The results show equivalent values in the deviations as well as in the declared uncertainties, for all participants.

Measuring system for calibrating high voltage instrument transformers at distorted waveforms

In high voltage power systems, harmonic content is measured at low voltage through the instrument transformers on the power grid. In this paper, a system for measuring the behavior of commercial current and voltages transformers under distorted waveforms is described. It generates programmable arbitrary waveforms and measures the ratio error at each harmonic order.

Eleven years of monitoring an ultra-stable 10 V zener-based voltage standard

The long-term behaviour of a voltage standard based on 140 zeners is analyzed. This standard was developed in 2004 and was monitored up to now. Noise and drift are evaluated showing better results than commercial similar devices. This source is used as the National Voltage Standard in the Uruguayan Designated National Metrology Institute (UTE).

Final report: Key comparison of 50/60 Hz power SIM.EM-K5

Under the auspices of the Committee Consultative of Electromagnetism, CCEM, the SIM Electromagnetic Working Group carried out a key comparison of power standards at 50/60 Hz. This key comparison, identified as SIM.EM-K5, aims to provide a link to various NMIs in the SIM region to the CCEM-K5 key comparison on 50/60 Hz power completed in 2001 and piloted by NIST. Measurements in the SIM.EM-K5 comparison were carried out from May 2010 to March 2012, including testing points of active and reactive power. CENAM was the pilot laboratory. Differences between the measurement results of the participating laboratories and the reference value of this key comparison, calculated at each of all the testing points, show a good infrastructure of national standards of measurement of electric power in the SIM region. Based on previous work, a link has been estimated between the results of the CCEM-K5 and the SIM.EM-K5 key comparisons, whose results were reported in 2002 and 2014, respectively. From the link it is shown that the measurement results of SIM.EM-K5 comparison are well supported. The SIM.EM-K5 comparison is a rewording exercise of comparison of the national standards of measurement as recommended by the CIPM. The participating laboratories are fully recommended for their enthusiastic participation in the comparison. Their individual efforts to maintain the national standards of power measurement are acknowledged. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Results of the SIM.EM-K5 key comparison of 50/60 Hz power

From years 2010 to 2012, a key comparison of power standards at 50/60 Hz was conducted in the SIM region. The comparison included measurements of active and reactive power at three frequencies, aiming at providing support to high accuracy measurement needs of reactive power. This paper presents the results of the SIM.EM-K5 comparison and the assessment of the link between this comparison and the CCEM-K5 key comparison on 50/60 Hz power completed in 2001.

AC Resistance Standards based on Calculable Resistors

It is described, in this paper, the design and construction of coaxial calculable resistors, with values of 140 W, and 1000 W, to be used as resistance standards in alternative current. Their behaviors are evaluated using simulation techniques and the step response. Impedance variations lower than 10-11 at 1600 Hz were obtained.

Error Compensation Of Current Transformers Used In High Voltage Networks

An error compensation technique for measuring current transformers is described. It uses only passive components. An example is shown for current transformers installed in I50 kV switching devices. Initial ratio errors in the order of 4% and phase shifts around 20 min were reduced to 0.1% and 6 min after the compensation. The transformer with the compensation fulfils class 0.2 according to IEC standards.