Relationship between partial discharge pulse height analysis and subsequent voltage endurance of stator bars and coils. Discussion

Especially if the results of voltage endurance tests are only marginally acceptable, there is a need to ensure that better stator bars or coils are installed in higher stress areas of the winding. A method has been developed for screening stator bars and coils using a particular type of partial discharge detector. Evidence is presented which suggests that the test method is more sensitive to internal discharges than to those associated with the end grading surfaces. The results of this test can be used to predict which bars or coils are more likely to fail voltage endurance in relatively short times