A DC blocking control device for a transformer and an error correction method for a data acquisition unit

Abstract

The present invention provides a transformer blocking controller and a data collection unit error correction method. A data collection unit comprises a PT mutual inductor for voltage sampling and a CT mutual inductor for current sampling, if the transformer blocking controller is a blocking mode, the direct current of a transformer neutral point is detected, if the detected direct current is not zero, it is determined that there is a null shift current error, and the null shift current error value is employed to perform direct correction of the CT sampling value in the grounding mode; if the transformer blocking controller is a direct grounding mode, the voltages of two ends of a blocking capacitor are detected, if the voltages of two ends of the blocking capacitor are not zero, it is determined that there is a null shift voltage error, and the null shift voltage error value is employed to perform correction of the PT sampling value in the blocking mode. The error correction method does not need human intervention, can eliminate errors of the current mutual inductor itself, the voltage mutual inductor itself, the line and other devices, improve the sampling precision of current or voltage and allow the blocking device to more stably and reliably operate.

Description

technical field [0001] The invention belongs to the field of calibration, verification and detection of electric equipment, and in particular relates to a transformer DC blocking control device and a data acquisition unit error correction method. Background technique [0002] Due to the serious imbalance between energy distribution and power load distribution in my country, and the development needs of the State Grid Corporation of China to build a strong and smart grid, HVDC transmission has developed rapidly in my country, and more than 20 lines have been built and put into operation, and the follow-up is under construction There are more than ten planned lines, and HVDC transmission has constituted an important part of the main grid of my country's power grid. When the unipolar or bipolar asymmetrical high-voltage DC transmission line operates with the earth as the loop, the huge DC current will have a greater impact on the AC system near the grounding pole. After the DC ...

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Problems solved by technology

[0007] The purpose of the present invention is to provide a transformer DC blocking control device and a data acquisition unit error correction method, which is used to solve the problem of low stability and low reliability of the DC blocking device in the prior art due to the sampling error of the transformer DC blocking device transformer question

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