Device for improving current sampling linear range and electric energy measuring accuracy of electric energy meter

Abstract

The invention discloses a device for improving a current sampling linear range and electric energy measuring accuracy of an electric energy meter. The device comprises a switching switch and a control sampling resistor, wherein the switching switch is in secondary connection with a current transformer of the electric energy meter; the control sampling resistor is in the secondary connection with the current transformer of the electric energy meter and is used for controlling and sampling a secondary side current; the switching switch is connected with an adjustable sampling resistor; resistance of the adjustable sampling resistor is adjusted through change of a switching point of the switching switch; the adjustable sampling resistor is connected with a metering chip through a low-pass filtering circuit; the control sampling resistor is connected with a comparer; the comparer is connected with a microcontroller; one path output of the microcontroller is connected with the metering chip; and the other path output of a microprocessor is connected with the switching switch. The device is reasonable in structure and good in working performance, and capable of improving the current sampling linear range and the electric energy measuring accuracy of the electric energy meter.

Description

technical field [0001] The invention relates to the field of electric energy metering of an electric energy meter, in particular to the field of high-accuracy electric energy metering in a wide current range or in an environment with impact loads. Background technique [0002] With the rapid development of smart grids in recent years, a large number of distributed power generation devices such as wind power and solar energy have been incorporated into the power grid; at the same time, the rapid economic development has made large-scale electric power plants with strong impact and serious distortion characteristics such as electrified railways and large steel plants. A large number of loads have emerged, and the power quality of some regional power grids, especially the medium and low-voltage local power grids, has been seriously affected; it is difficult for existing electric energy meters to measure electric energy accurately in this application environment, because current ...

AI Technical Summary

Problems solved by technology

When the primary side current is overloaded and the equivalent impedance of the secondary side is large, the magnetic circuit of the transformer coil will be saturated due to excessive excitation current, causing secondary current waveform distortion and phase changes, thereby affecting the measurement accuracy

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