Method and system for correcting voltage at two ends of low-voltage capacitor of capacitive voltage divider
A technology of capacitive voltage divider and low-voltage capacitor, which is applied in the direction of measuring current/voltage, instrument, measuring electric variable, etc.
Pending Publication Date: 2022-08-09
CHINA ELECTRIC POWER RES INST +3
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[0005] The present invention proposes a voltage correction method and system at both ends of a low-voltage capacitor of a capacitive voltage divider to solve the problem of how to correct the voltage at both ends of a low-voltage capacitor of a capacitive voltage transformer with a harmonic measurement function. question
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[0061] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for the purpose of this thorough and complete disclosure invention, and fully convey the scope of the invention to those skilled in the art. The terms used in the exemplary embodiments shown in the drawings are not intended to limit the invention. In the drawings, the same elements / elements are given the same reference numerals.
[0062] Unless otherwise defined, terms (including scientific and technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is to be understood that terms defined in commonly used dictionaries should be construed as having meanings consistent with the context in the related art, and should not be construed as idealized or overly formal...
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The invention discloses a method and a system for correcting voltages at two ends of a low-voltage capacitor of a capacitive voltage divider. The method comprises the following steps: acquiring a current to ground of the capacitive voltage divider and a measured voltage at two ends of the low-voltage capacitor of the capacitive voltage divider; performing signal decomposition on the measured voltage and the current to ground, and determining a fundamental wave and each harmonic signal corresponding to the measured voltage and a fundamental wave and each harmonic signal corresponding to the current to ground; calculating the impedance of the low-voltage capacitor end according to the fundamental wave and each harmonic signal corresponding to the measured voltage and the fundamental wave and each harmonic signal corresponding to the ground current; calculating equivalent capacitive reactance according to the high-voltage capacitance and the medium-voltage capacitance of the capacitive voltage divider; determining a voltage correction coefficient according to the impedance of the low-voltage capacitor end and the equivalent capacitive reactance; correcting the measured voltage according to the correction coefficient to obtain a corrected voltage; according to the method, the measurement accuracy of the power frequency and harmonic signals can be improved, and the high-accuracy requirement of a power quality monitoring system on a data source is met.
Description
technical field [0001] The present invention relates to the technical field of high-voltage insulation, and more particularly, to a voltage correction method and system at both ends of a low-voltage capacitor of a capacitive voltage divider. Background technique [0002] The harmonic voltage signal of the power grid needs to be measured by the secondary winding of the voltage transformer using a power analyzer, power quality monitoring terminal and other equipment. Accurate measurement. In my country, Capacitor voltage transformer (CVT) is the main sensing terminal for measuring system voltage in power systems of 110kV and above. However, it has obvious band-pass or band-rejection characteristics in certain frequency bands, resulting in The harmonic voltage waveform measured by the winding will produce different degrees of distortion, so it is difficult to accurately obtain the true level of the grid harmonic voltage directly through the CVT. [0003] In order to solve this...
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IPC IPC(8): G01R19/00G01R23/16
CPCG01R19/00G01R23/16Y02E40/40
Inventor 王玲冯宇陈晓明徐思恩邱进杜砚毛安澜刘坤雄
Owner CHINA ELECTRIC POWER RES INST