Circuit for eliminating voltage measurement error of high voltage standard capacitor divider

Abstract

The invention provides a circuit for eliminating voltage measurement error of a high voltage standard capacitor divider, comprising a double shielding coaxial cable and an error-eliminating circuit; wherein, the double shielding coaxial cable is connected between a high voltage arm gas compression standard capacitor and a low voltage arm mica capacitor; the error-eliminating circuit comprises a double difference amplifier circuit, a signal following circuit and an output bias regulating circuit; a low voltage signal input end of the double difference amplifier circuit is connected with an inner shielding layer of the double shielding coaxial cable; a measuring signal input end of the double difference amplifier circuit is connected with a core wire of the double shielding coaxial cable; two output ends of the double difference amplifier circuit are correspondingly connected with a reversal phase and same phase signal input end of the signal following circuit; the same phase input end of the signal following circuit is also connected with a signal output end of the output bias regulating circuit; an output end of the signal following circuit is used for connecting with measuring instruments.

Description

technical field [0001] The invention relates to a circuit for eliminating the voltage measurement error of a high-voltage standard capacitor voltage divider, in particular to a circuit for eliminating the measurement error caused by cable distributed capacitance in the voltage measurement of the high-voltage standard capacitor voltage divider. Background technique [0002] At present, in the capacitive voltage divider used for high-voltage accurate measurement, the compressed gas standard capacitor is used as the high-voltage arm C1 of the voltage divider, and the high-stability mica capacitor C2 is used as the low-voltage arm of the voltage divider, which has the advantages of simple structure, high sensitivity, and stable temperature. Good performance, strong adaptability, good dynamic performance and a series of advantages, figure 1 The schematic diagram of its structure is shown, the high-voltage arm compressed gas standard capacitor C1, the low-voltage arm mica capacito...

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Problems solved by technology

[0005] The above methods are all designed for the measurement of low-voltage capacitive sensors below 100KV, such as flat plate displacement sensors, which are characterized by low measurement voltage, small size of capacitive sensors for measurement, and short length of transmission cables, while they are used for high voltage In the accurately measured capacitive voltage divider, the measured voltage is as high as 120kV. The standard capacitor used as the high voltage arm of the voltage divider is relatively large (2000mm high, 500mm in diameter), and the length of the transmission cable is more than 10 meters. Therefore, the above method cannot be directly applied. In capacitive voltage divider for accurate measurement of high voltage above 100KV

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