New challenges in partial diacharge measurements

Measurement of partial discharges is one of the main nowadays used methods of diagnosis of electrical devices. Generators, transformers, cables and transmission lines are especially tested on the presence of PDs. New standards are being developed for the PD measurement under high frequency, for UHF measurement methods, etc. As the situation in transmission of electrical energy changes to long distance transport necessity, DC lines are developed, planned and constructed. This brings us to the problem of the diagnosis of PDs under new condition by the DC voltage of high levels. An aging process of the insulation under DC voltage need to be further studied and described. Paper deals with the description of PDs under DC voltage in comparison with AC.