Calibration system and calibration method of alternating large current of current transformer

Abstract

The invention discloses a calibration system and a calibration method of an alternating large current of a current transformer. The calibration system of the alternating large current of the current transformer comprises a large current sensing unit, a data collection unit and a personal computer (PC), wherein the large current sensing unit comprises an iron core coil, a hollow coil, a signal conditioning unit and a shielding case, the hollow coil and the signal conditioning unit are fixed inside the shielding case, the iron core coil, the hollow coil and the shielding case are respectively installed on a current-carrying wire, a first bypass wire is arranged between the iron coil and the hollow coil, and an output end of the signal conditioning unit is connected with the PC through the data collection unit. Mutual inductance coefficients of the installed hollow coil are calibrated through the iron core coil, whether a state of the hollow coil meets a calibration condition or not is judged, closed-loop control when calibration is conducted is finished through feedback of the mutual inductance coefficients of the hollow coil, the high-accuracy calibration on the alternating large current is achieved, and output accuracy of the current transformer with the hollow coil is ensured.

Description

technical field [0001] The invention specifically relates to a current transformer AC large current verification system and method based on the self-verification principle of the mutual inductance coefficient of an air-core coil, and belongs to the technical field of electric energy parameter measurement. Background technique [0002] With the rapid development of the power system, the voltage level of the power grid is constantly increasing, and the current is also increasing, but the performance of the metering equipment under high voltage and high current conditions is subject to greater tests. As one of the important metering equipment in substations, current mutual inductance More and more attention has been paid to the performance and calibration of converters under high current conditions. [0003] Traditional current transformer calibration equipment generally uses calibration equipment based on electromagnetic transformers, which can only calibrate the performance o...

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Problems solved by technology

[0006] 2) Although the series connection of multiple air-core coils can increase the output signal, it will also increase the internal resistance of the air-core coils, causing output errors;

[0007] 3) The measurement accuracy of the air-core coil is greatly affected by the installation position. Therefore, during high-current calibration, under the premise that the installation process and results are uncontrollable, the measurement accuracy of the air-core coil is also uncontrollable, and it is difficult to guarantee the current of the standard current channel. Measurement accuracy such that the credibility of calibration results is questioned

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