PROJECT TITLE :

SF6 decomposition of typical CT defect models

ABSTRACT:

Detection of decomposition merchandise may be a newly-rising technique for the condition diagnosis of SF6-insulated equipment. Based mostly on the 2 grading structures that are commonly adopted in SF6-insulated current Transformers (CT), three models consisting of the needle-to-plane, the ball-to-plane, and also the plane-to-plane were established. Gas decomposition was investigated in an exceedingly ninety L discharge chamber beneath operating conditions. Products were analyzed with gas chromatography (GC) and X-ray photoelectron spectroscopy (XPS). Typical gas decomposition merchandise are CF4, SO2F2, CS2, SO2, and S2OF10. For the needle-to-plane with a niche of thirty mm, near-linear growths with time are observed in the concentrations of SO2F2, SO2, and S2OF10 when the applied voltage is ready as thirty three kV. Addition of the adsorbent suppresses the concentrations of all 3 product, particularly SO2. Besides, CF4 and CS2 also are found to be the characteristic parts of partial discharge involving polyester films. And their concentrations are higher when the electrical field lines are parallel to the surface of the polyester. As for the polyester films, the atomic ratio of C decreases, the atomic ratio of S will increase, and the atomic ratio of F will increase significantly as the deterioration becomes more serious. Moreover, the concentration ratio of S2OF10/SO2F2 within the needle-to-plane is largely inside the vary of zero- 2, whether or not with the addition of adsorbent or not. And the ratio is much higher (two-10) when polyester is involved within the discharge method. It could be used to diagnose the insulation condition of CT effectively.