New apparatus for detecting transformer faults online

A new diagnostic apparatus for online detecting gases dissolved in transformer oil is described, in which polytetrafluoroethylene membrane with microholes is used to separate H/sub 2/, CO, CH/sub 4/, C/sub 2/H/sub 2/, C/sub 2/H/sub 4/ and C/sub 2/H/sub 6/ from the oil. Mixed gases are further separated to single gas by the multiple gas chromatograph columns, then they are detected with a new sensitive hot wire gas detector. The whole online chromatograph supervising system is inexpensive and proved to be useful in practice.