Gas-sensitive protection device and method for dry metallized film capacitor

Abstract

The invention discloses a protection device and method for a metallized film capacitor. The inside of the dry metallized film capacitor is not potted or adopts a potted dry structure, and a gap with certain height exists in the top of the capacitor. The gas-sensitive protection device formed by a thermal conductive hydrogen sensor and a detection circuit of the sensor is mounted at the top of the capacitor. When an element in the capacitor has a breakdown failure, a large amount of gas can be produced inside the element, escapes and can be gathered in the gap in the top of the capacitor finally. After the element produces the gas, the hydrogen volume accounts for about 85% through detection, thus, the produced gas can cause the concentration of hydrogen in the gap in the top of the capacitor to change, an output signal of the detection circuit can change, and the internal failure of the metallized film capacitor is detected. When a failure signal is detected, a power supply of the capacitor can be cut off from the outside, so that accidents such as capacitor explosions and the like caused by further development of the capacitor failure can be prevented, and failure detection and protection of the capacitor can be realized.

Description

Technical field [0001] The invention belongs to the technical field of electrical equipment, and more specifically, relates to a gas-sensitive protection device and method for dry metallized film capacitors. Background technique [0002] The metallized film capacitor is composed of metallized film. Because the thickness of the metal electrode is very thin, only nm level, it has self-healing characteristics. The insulation can be restored after the internal electric weak click through, and it can work under the critical breakdown field strength. The energy storage density of the dielectric membrane is improved, and the volume of the energy storage element is reduced. At present, metallized film capacitors are often used as energy storage devices for pulsed power sources, or used in power system AC and DC filtering and reactive power compensation. [0003] When the internal medium of the metallized film capacitor is obviously aging, operating in a high temperature environment, the w...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the above defects or improvement needs of the prior art, the present invention provides a dry-type metallized film capacitor gas-sensing protection device and method. Detect the internal fault of the capacitor and give a signal to cut off the power supply of the dry metallized film capacitor, thereby overcoming the technical problem of poor reliability in the existing method

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