In order to detect partial discharge fault of the gas chamber inside SF

6

gas insulated RMU

the SF

6

PD isstudied by decomposition product component analysis. SF

6

decomposition products and decomposition characteris-tics are researched by experiment under different discharge intensity and metal protrusion defect is equivalent byneedle-plane electrode. Four different voltage levels are applied to generate different discharge int

ensities. The sam-ple gas is collected every 12 h and the decomposition components are detected by gas chromatography-mass spec-trometry（GC/MS）. The results show that PD initiated by needle-plate insulation defect will cause SF

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decomposing in-to the stable decomposition components such as

CO

2

SO

2

F

2

SOF

2

and SO

2

under AC voltage. The concentration ofthe four components is affected by the discharge time and strength. The concentration of these four components con-centration is increasing over time

and a saturated tendency is exhibited. And the concentration increases with in-creasing amount of discharge

and show different patterns about different components. According to the above study

a correspondence is established between the decomposition component gas rate and the discharge intensity. So thedischarge intensity could be inferred based on the effective rate of gas production which provides an analysis methodof components used in SF

6

gas insulated RMU.