Effect of Polarity Reversal on Space Charge Dynamics of HVDC Cable Insulation at Different Electric Fields

HVDC underground cable insulation undergo charge injection leading to space charge formation in the insulation bulk. These injected charges lead to electric field distortion in the insulation. Polarity reversals in the LCC converter-based topology have been observed to further significantly degrade the cable insulation. The reversals affect the charge distribution leading to premature breakdown of the cable insulation. This polarity reversal scenario hence becomes a necessity to investigate and understand the charge transfer mechanism. In this work LDPE planar samples are stressed at different electric fields and subjected to different polarity reversal intervals. The space charge is measured and the charge transfer mechanisms are studied. An attempt to find the correlation between the effect of polarity reversal time and electric field magnitude has been made.