The qualitative and quantitative determination of gases released from SF6 electrical equipments plays an important role in diagnosing the failure of SF6 electric equipments. In this work

17 gases were determined based on a dualchannel gas chromatography (GC) equipped with a helium ionization detector in GIS (Gas Insulated Switchgear)

including CO

CF

4

CH

4

CO

2

C

2

F

6

C

2

H

2

COS

C

2

H

4

C

2

H

8

H

2

S

SO

2

F

2

C

3

F

8

C

3

H

6

C

3

H

8

CS

2

SO

2

and S

2

OF

10

. Gases were transported into channel A and channel B of the instrument. Channel A was composed of a 05 nm column and a Poropak Q column while channel B was made up of HP-5 capillary chromatographic column. As a result

target compounds could be separated completely. Moreover

the limit of detection (LOD) of these gases was approximate 10

-8

and the relative standard deviation (RSD) was less than 7%. Therefore

the proposed method was sensitive

precise and was finally applied to determine 15 gases in real samples from GIS. SO

2

and SO

2

F

2

could be detected in the GIS

which indicated the spark discharge inside the equipment.