Circuit and method for testing voltage-sharing capacitance of high-voltage direct-current transmission converter valve assembly

Abstract

The invention provides a high-voltage direct-current transmission converter valve assembly voltage-sharing capacitor test circuit and method, a converter valve assembly comprises a plurality of thyristor levels connected in series, an assembly voltage-sharing capacitor is connected in parallel to two ends of a series branch of the plurality of thyristor levels connected in series, and a test voltage source and a sampling resistor are connected in series and then are connected in parallel to two ends of the assembly voltage-sharing capacitor; the follower comprises an operational amplifier, the test voltage source is connected to the input positive end of the operational amplifier through a sampling resistor, and the input negative end of the operational amplifier is connected with the output end and then connected to any position between the thyristor levels connected in series; and the output end of the follower is in a high-resistance state. The current value flowing through the component voltage-sharing capacitor can be accurately calculated by collecting the voltage at the two ends of the sampling resistor, and the capacitance value of the component voltage-sharing capacitor is obtained according to the voltage and the current value of the component voltage-sharing capacitor. According to the invention, the testing process of the component voltage-sharing capacitor is simplified, and the accuracy and the working efficiency are improved.

Description

technical field [0001] The invention relates to the technical field of high-voltage direct current transmission converter valves, and in particular relates to a test circuit and method for a voltage-equalizing capacitance of a high-voltage direct current transmission converter valve assembly. Background technique [0002] The converter valve is an important component in the HVDC transmission project, which is of great significance to the safe operation of the HVDC transmission. In order to meet the high voltage requirements of the converter valve, a single converter valve consists of multiple thyristors in series, generally 6 to 15 thyristor stages are connected in series to form a valve assembly, and then a valve tower is composed of multiple valve assemblies, each valve hall. A plurality of valve towers are also installed. The distribution of stray capacitances in the valve tower is very complex. These stray capacitances may cause unbalanced voltage distribution in the ca...

AI Technical Summary

Problems solved by technology

However, since there are hundreds of valve components in a single converter station, it is a huge task to measure the parameters of the pressure equalizing capacitance of the valve components during maintenance.

The traditional method of testing the voltage equalizing capacitance of the valve assembly is mainly to use a multimeter, an electric bridge, etc. for direct testing. This method needs to remove the original circuit and measure one by one, which can ensure the accuracy of the test, but it is easy to cause contact between the connectors when the circuit is restored. Problems such as resistance exceeding the standard, there are potential safety hazards

Moreover, the testing work steps are cumbersome and the efficiency is very low

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