The accuracy of the DC voltage measurements higher than 10 V depends on the accuracy of DC voltage ratio measurements. Reference standards for DC voltage ratio measurements are resistive voltage dividers which are generally self calibrated by their own bridges. Calibration of a absolute voltage divider with wide ratio range, such a Datron 4902S, using its bridge is difficult and time consuming calibration. Three different methods for the calibration have been investigated in order to make simpler divider calibration without losing from uncertainty. An extensive set of measurements were...
This paper presents a new nondestructive testing method. The conductive material being tested moves in a time constant magnetic field. Due to the movement the induced currents in the conductor generate a secondary magnetic field. When the eddy current flow pattern is disturbed by the existence of defects, variations of the magnetic field occur and information about the defects can be assessed by measuring the magnetic field.
This paper describes an automatic characterization system designed for the measurement of the electric impedance of Giant Magneto-Impedance (GMI) samples. The high speed of measurement attained with the use of this system, designed in the LabVIEW development environment, allows for the rapid determination of the optimal operational point of an eventual GMI magnetometer.
This paper analyzes the possibility of utilizing the measurement results made by smartmeters to decrease the number of customers affected by prolonged outages so increasing smart grid reliability. For this scope this paper proposes a continuous monitoring of system impedance so that it would be possible to detect the progressive degradation of some system component and to assert its localization with certain accuracy. The approach is based on theory developed for fault location and theory of synchrophasors. Some experimental results, obtained with the presented approach are reported.
In the case of calibration of direct acting indicating analogue electrical measuring instruments (hereinafter called the "analogue instruments"), uncertainty budget largely depends on dispersion of readings for scales through a needle. This paper describes experimental results for three levels of voltage (10 V, 6 V, and 3 V) of analogue instruments. In the experiments, two way layout nested design was introduced for each voltage level. From the results of present experiments, it was revealed that expanded uncertainties obtained were about 1/3 for the specification that obtained from the past...
A metrological AFM is designed to establish a traceable standard with nanometer uncertainty. The principle and design of the instrument is introduced in this paper. The displacement of the sample is traced to the SI unit by interferometers. The metrological AFM is applied to step height and line width measurement. The results are compared with optical instrument and profilometers. The metrological AFM participates step height international comparison and the result shows an uncertainty less than 2 nm.
Methods for on-site calibration of the components in current transformer (CT) testing systems in industry have been developed, which do not require any component to be detached from the systems. The method utilizes several travelling transfer standards. The on-site calibration method using these travelling transfer standards has been successfully applied to calibration of CT testing systems in industries.
This paper focused to determination of Voltage dependence of Precision High Voltage divider and Self Heating of HV resistance. High Voltage resistive divider is a Primary standard of DC High Voltage measurements. The traceability of HV measurements is directly related to divider’s traceability, to scale the voltage from Josephson voltage standard, which is primary standard of DC voltage. The change in effective resistance ratio with Voltage depends upon self heating of resistance, electrostatic stress and leakage current. The design of divider and Precision source minimise the above factor...
The leakage inductance and direct current (DC) resistance of windings are the most informationbearing parameters for diagnosis of voltage transformers. Measurement of these parameters with improved speed and accuracy by step function is suggested.
The development trends of electrical networks clearly indicate that grids of the future will include more and more smart components. In the new smart grids, smart components fulfill measurement and control tasks: in this scenario, not only the simple energy consumption, but also other parameters have to be measured. Among these parameters certainly there is the quality of energy. Therefore new smart meters have to face the issue to measure energy consumption and energy quality over a wide frequency range. Therefore, in order to make possible the implementation of a smart meter with standard...