High-precision capacitance voltage division type voltage transformer and voltage measurement method

Abstract

The invention relates to a high-precision capacitance voltage division type voltage transformer and a voltage measurement method. The high-precision capacitance voltage division type voltage transformer comprises a measurement voltage division branch formed by connecting a measurement high-voltage capacitor and a measurement low-voltage capacitor in series, and the measurement voltage division branch is connected between a to-be-measured high-voltage line and a grounding line and is parallel to the to-be-measured high-voltage line. The high-precision capacitance voltage division type voltage transformer is characterized in that a reference voltage division branch formed by connecting a reference high-voltage capacitor and a reference low-voltage capacitor in series is arranged, the reference voltage division branch is also connected between the to-be-measured high-voltage line and a grounding line, the reference voltage division branch is parallel to the measurement voltage division branch and the to-be-measured high-voltage line, a first voltage division signal is led out between the measurement high-voltage capacitor and the measurement low-voltage capacitor, and a second voltagedivision signal is led out between the reference high-voltage capacitor and the reference low-voltage capacitor. According to the high-precision capacitance voltage division type voltage transformerand the voltage measurement method, the reference voltage division branch is arranged, so that the capacitance value of the high-voltage parasitic capacitor is calculated, the measurement value of thevoltage transformer is further corrected, and the measurement precision is improved.

Description

technical field [0001] The invention discloses a high-precision capacitive voltage-dividing voltage transformer and a voltage measurement method, which belong to the technical field of electrical engineering measurement. Background technique [0002] When measuring high voltage in the power system, capacitive voltage division or resistance voltage division is usually used to convert the high voltage to be measured into a small voltage signal to facilitate the measurement of secondary equipment. The voltage transformer of the voltage mode can eliminate the influence on the line impedance, but the existence of parasitic capacitance is the main cause of the measurement error no matter the resistance voltage division or the capacitance voltage division mode. [0003] For capacitor voltage divider voltage transformers, the principle of voltage measurement by capacitor voltage division is: use a high-voltage capacitor (pF level) and a low-voltage capacitor in series (nF level), th...

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Problems solved by technology

[0009] In the prior art, to solve the parasitic capacitance on the image 3 The solution to the influence of the voltage transformer of the structure shown is to measure the actual error of each set of voltage transformers before the product leaves the factory, and then cooperate with the terminal to set a special correction coefficient for the transformer. This method undoubtedly increases the test personnel. The workload; more importantly, after the transformer is installed in the distribution transformer, different distribution transformers have different operating environments, especially the influence of external electric fields, which will make the correction system written into the low-voltage side terminal before leaving the factory It is no longer applicable, and the method of using on-site calibration shows that it cannot be implemented in practical applications, so the application accuracy of the above products is difficult to guarantee

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