Partial discharge database: its benefits and limitations on assessment of stator insulation deterioration

PD test data on various generators and motors has been collected over the last 15 years using on-line partial discharge analyzers. A large PD test database has been established. The database provides an overall view of PD activity on rotating machines. Statistical analysis of the database provides a study of PD distribution with variations of a number of the parameters. This paper presents statistical analysis of a large PD database accumulated over the last 15 years. The statistical analysis shows distribution of PD levels with machine type, voltage rating, sensitivity of the PD sensor, etc. The benefits and limitations of the PD database on assessment of stator insulation condition are discussed in the paper