Statistical estimation method of remaining BDV and life expectancy for generator stator winding by using nondestructive insulation diagnostic data

With the aim of properly estimating the remaining breakdown voltage (BDV) and life expectancy of generator stator winding insulation from nondestructive insulation diagnosis data, we have collected BDV and nondestructive data of the stator windings removed from 15 generators with rated voltage of 6.6 to 15.4 kV. Recently, we have calculated statistical correlation between BDV and nondestructive data for these coils, established statistical method of estimating remaining BDV by nondestructive insulation characteristics and multiple regression analysis, and are applying diagnosis for the operating generators.