Metallized film capacitor has high working field strength and reliability due to its self-healing characteristics

but a large amount of gas will be generated during the self-healing process of the capacitor

which affects seriously operation reliability of the capacitor. In this paper

the el

ement of the metallized polypropylene film capacitor is taken as the research object

the relationship between the self-healing gas production and the capacitance loss is analyzed. The operating threshold for pressure protection is calculated. And the gas component produced by the self-healing of the capacitor is measured by gas chromatography. The gas production characteristics of the capacitor in the enclosed environment are studied on the basis of ammonia sensor. The research results show that the gas production volume in the self-healing process is approximately linear with its capacitance loss. The gas produced by the self-healing of the metallized polypropylene film capacitor mainly contains H

2

C

2

H

2

CH

4

and CO

and the self-healing will also produce amorphous carbon element. The Hydrogen concentration in the enclosed environment during the continuous self-healing process of the capacitor is proportional to the pressurization time. In case of short circuit of the capacitor

the Hydrogen concentration will increase rapidly and the hydrogen sensing device can accurately detect this phenomenon.