Discussion on the relation between residual breakdown voltage and nondestructive parameters of stator insulation in generator

A long-term accelerated aging test of generator stator insulation in the laboratory was conducted. Nondestructive parameters, such as dissipation factor (tan /spl delta/), capacitance (C) and the voltage (U/sub 12/) at which the current increases abruptly, were measured in the period of the aging test. The breakdown test was performed to determine residual breakdown voltage (BDV). The correlation coefficients between BDV and nondestructive parameters were compared. The most effective parameter to describe the aging condition of the stator insulation was U/sub 12/. The relationship between BDV and nondestructive parameters was also analyzed theoretically.