ISBN:  Unavailable

Category: Unavailable

Page count: 22

Study provides condition assessment, the rate of aging and remaining service life estimation of the regulating rectifier transformers D6, D7 and D8 in Talum Group in the year 2015. The condition assessment is based on evaluation of insulating system condition with periodic physico-chemical tests such as dissolved gasin oil analysis by gas chromatography, furanics in oilamnalysis by high performance liquid chromatography and physico-chemical properties of the transformers oil, carried out at the EIMV over the past 27 years and on the review of available data of operating temperatures, loading and of cooling system profiles. The assessment of the ageing rate by estimation of the lowest DP in transformer is based on the 2FAL-DP EJMV correlation curves. Estimation of the 3 transformers' service life expectancy is based on the world-wide commonly accepted minimum paper DP criteria and evaluation of solid insulation humidity. Estimation of expected service life of the three transformers is based on the assumption that their future load profile will be simi1ar to the one of the last 8 years. Comparison of the expected service life in the year 2015, with preliminary estimates of the years 2003, 2005 and 2007 shows that the service life of the rectifier transformers D6, D7 and D8 transformers have been successfully extended by the EIMV previously suggested measures of preventive maintenance (oil type exchange and lowering of the operating temperature of the transformers by cooling optimization), carried out in the years 2003-2005.