| 摘要 |
A method for removing copper sulphide (Cu 2 S) deposited onto electrically insulating materials of components in an electrical apparatus, such as a transformer or a bushing, wherein normally present electrically insulating oil has been substantially removed, and on other surfaces of such apparatus, comprising the following steps: providing a chemical treatment solution comprising a polar aprotic solvent, and preferably a chelating agent being able of forming complexes with copper from the surface of Cu 2 S deposited onto the insulating material, said chelating agent containing free electrons capable of forming a complexation with Cu, being at least a bidentate, but preferably a multidentate, i.e. being able of forming complexes with Cu from more than one point in the chelating agent, and having a solubility in the polar aprotic solvent of at least 5·10 -4 mol/L to allow extraction of copper by solvation of the formed copper-chelating complex; and optionally additional components, said chemical treatment solution being non-aqueous; subjecting the insulating material to the solution, preferably at a temperature of 30-130 °C, more preferably 50-90°C, for a predetermined time period, preferably 2 to 10 days, more preferably 3 to 7 days; and removing the chemical treatment solution from the insulating material.
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