Abstract: Only after one-year operation severe turbine oil deterioration occurs at two 660-MW units of one power plant showing breen color. The analysis on oil quality and antioxidant is then carried out. It turns out that the diphenylamine antioxidant was added inappropriately to the fresh oil which causes the turbine oil to deteriorate rapidly in high-temperature operation. Based on the analysis result, the oil is treated with oil processing equipment and the T501 antioxidant is added to eliminate the adverse effects of improper antioxidants on oil. Moreover, it is suggested that specifications on oil additives should be put forward to ensure that the oxidation- resistance performance of fresh oils can meet related technical requirements.

Key words: turbine oil, diphenylamine antioxidant, oil deterioration, regenerative treatment