Test Set-Up and Preliminary Results of PD Measurements Performed During Thermal Cycles Applied to Different Types of MV Cable Joints

The experimental set-up and the first results of PD measurements performed to evaluate different types of MV cable-joints under electrical and thermal stresses, are discussed in the paper. Twelve cables equipped with different types of joints were connected together to form a ring in short-circuit. The ring was enegized at rated voltage and current. Cycles of temperature having a period of one day have been applied by controlling the current by means of external coils. PD were monitored during the heating and cooling of the cables. Problems related to calibration and signal interference between the different cables, have been examined. The PD inception and the evolution of PD patterns due to the formation of defects in some joints, are discussed.