Method for calibrating errors of electric energy meter under influence of direct currents and even-order harmonic

Abstract

The invention provides a method for calibrating errors of an electric energy meter under influence of direct currents and even-order harmonic. According to the method, self-balance of two paths of impedance is achieved, one operational amplifier OP07 is used for detecting voltage drop at the two ends of the detected meter, and the voltage reflects impedance of the detected meter; the other operational amplifier OP07 is used for detecting voltage drop at the two ends of a balanced line, namely the voltage drop at the two ends of a field effect tube, and the voltage reflects impedance at the two ends of the balanced line; the two paths of voltage are sent to a comparator to be compared, the comparator can operate by means of the operational amplifiers OP07, the comparator compares the voltage reflecting the two paths of impedance and outputs a comparison result to a grid which controls the voltage to be connected with the field effect tube IRFP250, and conductor impedance of the field effect tube is also controlled. By means of closed-loop automatic control, the balanced impedance can be equal to the impedance of the detected meter, so automatic balance of the impedance of the balanced line and the impedance of a detected meter line is achieved. The method is suitable for calibrating the errors of the electric energy meter under influence of the direct currents and the even-order harmonic.

Description

[0001] technical field [0002] The invention relates to an error checking method of an electric energy meter under the influence of direct current and even harmonics, which belongs to the technical field of electric power measurement. Background technique [0003] With the development of science and technology, a large number of new nonlinear power electronic devices have been widely used. At the same time, they also inject various electromagnetic disturbances such as harmonics into the power grid. The influence of harmonics on the measurement accuracy of electric energy meters has been paid more and more attention by people. National Standard GB / T 17215.321-2008 Special Requirements for Alternating Current Measuring Equipment Part 21: Static Active Energy Meters (Class 1 and Class 2) Article 8.2.3 requires direct current and even harmonic influence tests on watt-hour meters, and provides Refer to the test circuit, the schematic diagram is as follows figure 1 As show...

AI Technical Summary

Problems solved by technology

[0007]The purpose of the present invention is to solve the problem that the standard special waveform cannot be generated at present and cannot meet the needs of the electric energy meter verification. The method of checking the error of electric energy meter under the influence of waves

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