Protection performance verification method for internal fuses of high voltage capacitor unit

Abstract

The invention provides a protection performance verification method for internal fuses of a high voltage capacitor unit. The verification method comprises the steps: establishing an equivalent circuit when one capacitor element is broken down in a capacitor unit; solving the equivalent circuit, and acquiring the current expression flowing through a capacitor element subcircuit; according to the current expression and the internal fuse resistance, calculating the energy of the tandem internal fuses, wherein the energy is injected into the capacitor element and breaks down the capacitor element; and determining whether the internal fuses used in the high voltage capacitor unit can be reliably fused by means of combination of the parameters of the whole capacitor device and the material and the size of the internal fuses. The protection performance verification method for internal fuses of a high voltage capacitor unit can accurately determine whether the internal fuses selected by the high voltage capacitor unit can be reliably fused, and can provide reliable guarantee for selecting suitable internal fuses for the high voltage capacitor unit.

Description

technical field [0001] The invention relates to the technical field of power capacitors, in particular to a method for verifying the protection performance of an internal fuse in a high-voltage capacitor unit. Background technique [0002] In the power system, the capacitor device is composed of multiple capacitor units connected in series and parallel, and the interior of the capacitor unit is composed of multiple capacitor elements connected in series and parallel, and each capacitor element is connected to the power supply through an internal fuse. The internal fuse is one of the main measures for the short-circuit fault protection between the poles of the high-voltage capacitor. The function of the internal fuse is to use the short-circuit discharge energy to fuse the internal fuse body and disconnect the branch circuit where the short-circuit capacitor element is located when the capacitor element is short-circuited. , isolates the shorted capacitor element from the pow...

AI Technical Summary

Problems solved by technology

[0004] The size of the internal fuse should not be selected too large, nor should it be selected too small. If the size of the internal fuse is too large, the internal fuse cannot be fused or cannot be reliably fused when the component breaks down, and even intermittent arcs will occur, resulting in the expansion of the fault; A small size will cause the internal fuse to blow or damage the fuse during normal operation or routine testing, resulting in the capacitor not working properly

At present, the size of the fuse in the capacitor unit is mainly selected by the capacitor manufacturer based on experience. There is a lack of accurate theoretical calculations as a support. There have also been many cases in the project where protection malfunction or fault expansion has occurred due to unreasonable internal fuse configuration.

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