A novel, compact instrument for the measurement and evaluation of relaxation currents conceived for on-site diagnosis of electric power apparatus

Ageing of insulation materials and systems may well be detected by quantitative measurements of their dielectric response. Such measurements can be performed in the frequency or time domain. In this contribution, a novel type of equipment based on relaxation current measurements is introduced which is designed for on-site tests of high voltage power apparatus. The introduction outlines the reasons for the development. Then, the technique of the instrument is briefly explained. Finally, some examples of on-site measurements on power transformers are presented and post-processing and interpretation of the results is demonstrated.