Abstract
Measurement method of Insulation diagnosis for 22 kV cable has not yet been fully established. We measured electrical properties of the cables with different degradation grade by various methods. As a result, we found some desirable methods of insulation deterioration for future study. For DC leakage current and tanδ measurements, it is possible to analyze their effective data using these insulation diagnosis methods. Measurements of residual charge, loss current and transient current under DC superimposition enable us to detect the insulation degradation. Therefore it is necessary to gather a lot of data using these method for an effective insulation diagnosis. In this study, we also discussed the generating mechanism of residual charge and loss current, and influence of outer semiconductor layer in these methods.
