Jiangtao Zhang

A New Method for Measuring the Level Dependence of AC Shunts

We describe a method of the measurement of level dependence in AC-DC difference of current shunts. The method is based on the use of a binary inductive bridge. The measuring principle and measurement results of a 1 A AC shunt at frequencies up to 100 kHz are presented.

A Coaxial Time Constant Standard for the Determination of Phase Angle Errors of Current Shunts

This paper describes a new method to determine the phase angle errors of ac shunts by measuring the inductance and distributed capacitance. A 1-Ω shunt of coaxial design has been developed as the time constant standard. A coaxial inductor with identical structure as the time constant standard has been developed. A four-terminal mutual inductor has also been built for the measurement of the inductance of the time constant standard. The method is based on the use of a binary inductive current divider to compare the inductor with the mutual inductor. The standard uncertainty of the inductance measurement of the time constant standard is within 28 pH at frequencies up to 200 kHz. The expanded uncertainty of the phase angle errors is from 0.4 μrad at 1 kHz to 80.0 μrad at 200 kHz at 1 A.

Determination of the phase error of 8∶1 Inductive Voltage Divider

This paper describes the development of Inductive Voltage Divider (IVD) with the ratio of 8:1 by means of the combination of three binary IVDs. The self-calibration method of the ratio error and phase error of the binary IVD was reported. We also report the determination of the phase error of a 8:1 IVD which has relative higher input impedance by comparing with the known phase error self-calibrated 8:1 IVD.

Traceability of digital electricity meters

We propose a scheme for traceability of digital electricity meters. For standard digital electricity meters, the analog-based method should be used. For installing digital electricity meters, the digital-based method can be used. In the process of quantization of sampling values, rounding error brings uncertainty to the computation of power. In this paper we analyze the uncertainty caused by rounding error by simulation.

Determination of the equivalent inductance of current shunts

This paper describes the determination of the equivalent inductance of current shunts from 1 A to 10 A at the frequency from 50 kHz to 200 kHz. The equivalent inductances were measured against a set of four-terminal resistor whose time constants were precisely known. The standard uncertainty was evaluated to be within 0.03 nH.

Phase comparator based on binary inductive current divider up to 200 kHz

A phase comparator has been developed to compare the phase angle of AC shunts at frequency up to 200 kHz at National Institute of Metrology (NIM) in China. The comparator can supply two currents in which one of the current is two times of the other. With this comparator, the phase angle of two AC shunts can be compared both in nominal current.

Calibration method for digital energy meters in digital substations

Digital energy meters are used in digital substations to measure electric energy, which receive IEC 61850 digital input. The traditional calibration methods for analog energy meters are not applicable to digital energy meters. In this paper we propose a method to calibrate digital energy meters.

Self-calibration of the binary inductive voltage divider at frequencies up to 1MHz

The binary inductive voltage dividers (BIVD) have been designed as the 2:1 ratio reference at frequencies up to 1MHz. In this paper, the BIVDs are described in detail together with the calibration of their ratio errors by a substitution method. The measurement results of the BIVDs have also been given at frequencies from 1 kHz to 1MHz.

Using inductive voltage divider to measure the millivolt ac voltage at frequencies up to 100 kHz

A method to measure the millivolt ac voltage has been described. The method is based on use of the binary inductive voltage divider and 2n:1IVDs. The measurement setup for the calibration of the 2n:1IVD has been proposed and the results have also been given at frequencies up to 100 kHz.

Measurement of the equivalent inductance of the high current shunts

We describe a method for the measurement of the equivalent inductance of the high current shunts against a four-terminal mutual inductance with the lock-in amplifier by means of the substitution method. The measurement results of Fluke A40B and metal foil shunts developed by BEV Austria at 50 A and 100 A at frequency up to 200 kHz are presented.